Surface and Interfaces of Nanocarbons

Resume : Systemic lupus erythematosus (SLE) is one of the most frequent autoimmune diseases. A major characteristic of this disease is the production by immune cells (called B lymphocytes) of antibodies, which recognise our own body components and thus participate to lupus development. Already existing treatments harbor low efficiency and induce severe side effects as they do not affect only pathogenic cells but all immune cells. It is therefore essential to design new therapies that affect only the pathogenic B cells involved in disease initiation and exacerbation. In this context, we designed a novel therapeutic approach relying on the use of carbon nanotubes (CNTs) as drug delivery systems to target B cells. Due to their outstanding physicochemical properties, the applications of CNTs in nanomedicine have been extensively explored.[1] Thanks to their high aspect ratio and tubular shape, they have the capacity to easily cross biological barriers and to be internalised in cells. Functionalisation is a key step to increase the dispersibility and biocompatibility of CNTs, to conjugate bioactive molecules and also to impart multimodality.[2] Our approach of using CNTs as carriers to target B cells is promising not only for SLE but also for any B cell-mediated disease. [1] Loh K. P. et al. Adv. Mater. 2018;30:1802368. [2] Dinesh B. et al. Nanoscale 2016;8:18596.

Resume : Photodynamic therapy uses photosensitisers such as protoporphyrin IX (PpIX) to target tumours via singlet oxygen release when irradiated. Treatment effectiveness is limited by inefficient drug accumulation in target tissue and high dark toxicity. Carbon dots (CDs) are biocompatible fluorescent nanoparticles which can improve PpIX cellular uptake and solubility. Conjugates were synthesised by host-guest encapsulation (PpIX@CD) and amide cross-linking (PpIX-CD). Characterisation with UV/Vis, PL, FT-IR, XPS, TGA, and TEM showed 34 - 48% loading efficiency and similar singlet oxygen production to PpIX. Dark toxicity was evaluated using C8161 melanoma at 1 - 100 µg/ml and phototoxicity was evaluated at 1 - 10 µg/ml. PpIX-CD and PpIX@CD showed a 3.2 to 4.1-fold increase in photo-toxicity index (PI) at concentrations >1 µg/ml mostly due to decreased dark toxicity. 3D tumour spheroids were used to observe effectiveness in a hypoxic environment at multiple fluence rates and doses (2.5 - 10 J/cm2) with LDH release and DNA quantification assays. Spheroids showed significant cell death and loss of sphericity seen at higher doses in comparison to 2D cell culture. Conjugates were imaged confocal microscopy and light sheet fluorescence microscopy, demonstrating rapid intracellular uptake. Our results demonstrate variations between cross-linking strategies in CD-based conjugates, highlighting their potential as carriers in drug delivery and bioimaging applications. Amide cross-linking requires additional processing steps but are less heterogeneous than conjugates produced via host-guest encapsulation. Additionally, the use of 3D cell models provides more relevant results due to their similarities with in vivo conditions.

Resume : Viral infections cover more than 90% of human infectious pathologies. Efficiency of the current antiviral drugs is severely restricted by their narrow action spectra, development of drug-resistant viral strains and appearance of toxicity effects. Therefore, there is an urgent need for development of new types of antivirals with superior performance. In that context, water-soluble fullerene derivatives demonstrated impressive antiviral properties sometimes overcoming commercial drugs against HIV, CMV, HSV, Hepatitis C, Influenza, and Stomatitis viruses. Importantly, some fullerene derivatives inhibit simultaneously several viral targets, thus suppressing significantly the formation of drug resistance. Recently we reported a number of efficient and selective methods for chemical synthesis of a broad range of water-soluble fullerene derivatives [Chem. Commun. 2012, 48, 5461; Chem. Commun. 2011, 47, 8298; Chem. Commun. 2012, 48, 7158], which substantially decreased costs of these compounds and made them available in bulk quantities for biological studies. Here we present three new synthetic routes for conversion of readily available C60Cl6 and C70Cl8 precursors to a variety of water-soluble fullerene derivatives bearing 4 to 16 carboxylic groups in their molecular frameworks. Multiple compounds revealed low toxicity in combination with a potent activity against Influenza, HIV, CMV, and HSV, which makes them promising lead compounds for the development of novel antiviral drugs.

Resume : Rapid development in two-dimensional nanomaterials and their biomedical applications have raised fundamental questions about their biointeractions1. However, any control over these interactions rely on the understanding their mode of action. Due to their high polydispersity and poorly defined structures, the mechanism of the biointeractions of two-dimensional nanomaterials is a controversial topic2. For a comprehensive study of these interactions, and to obtain reproducible results at nanobiointerfaces, the structure of these nanomaterials, in particular their exposed surfaces, should be defined. Recently, we have developed a method for a controlled functionalization of different two-dimensional nanomaterials by which we have synthesized several smart systems with well-defined functionalities, dimensions, and isoelectric points (pI)3. We found that cellular uptake pathways and intracellular localization of these 2D nanomaterials strongly depended on their surface charge and functionality4. By manipulating these factors, we were able to construct new two-dimensional nanomaterials with the ability to overcome multiple drug resistance in cancer cells5. Keywords: Two-dimensional nanomaterials, Graphene, Polyglycerol, Cancer 1. Z. Tu, G. Guday, M. Adeli, R. Haag. Advanced Materials, 2018, 1706709. 2. G. Reina, J. M. González-Domínguez, A. Criado, E. Vázquez, A. Bianco, M. Prato, Chem. Soc. Rev. 2017, 46, 4400. 3. A. Faghani, I. S. Donskyi, M. Fardin Gholami, B. Ziem, A. Lippitz, W. E. S. Unger, C. Böttcher, J. P. Rabe, R. Haag, M. Adeli, Angew. Chemie Int. Ed. 2017, 56, 2675. 4. Z. Tu, K. Achazi, A. Schulz, R. Mülhaupt, S. Thierbach, E. Rühl, M. Adeli, R. Haag, Adv. Funct. Mater. 2017, 27, 1701837. 5. Z. Tu, H. Qiao, Y. Yan, G. Guday, W. Chen, M. Adeli, R. Haag, Angew. Chem. Int. Ed. 2018, 57, 11198.

Resume : Diamond possesses unique surface properties that make it an an excellent candidate electron field emitter. Besides its robustness and quasi chemical inertness, the negative electron affinity when H-terminated plays a key role. Nevertheless, to reach its full potential in exhibiting superior electron field emission, the problem of the low electrical conductivity of bulk diamond, due to its wide band gap, must be overcome. Using polycrystalline diamond layers, composed of sp³-bonded diamond grains embedded in an amorphous / graphitic sp²-bonded carbon matrix forming the grain boundaries, a succesfull strategy to manipulate the conductivity of the material is to alter the microstructure of grains and grain boundaries. This can be done in several ways, including renuclation during growth, in-situ doping, and post-deposition ion implantation of several active elements. In addition, the fabrication of 3D structures, be it by adapting the deposition conditions, or by post-growth structuring via etching, enable to further influence the surface properties in a beneficial way, with great impact on the observed electron emission currents. Several strategies will be discussed and compared. The emission data will be correlated with structural information obtained by advanced transmission electron microscopy techniques. Electron field emission currents, including longterm stability and application in microplasma devices, underpin the observations. Finally, hybrid structures of diamond with other novel materials such as hexagonal boron nitride, graphene, etc, will be considered in relation to their electron emission properties.

Resume : Several techniques have been developed for the detection of carbon nanotubes (CNT) dispersed under the surface of a nanoscale polymer matrix, but Electrostatic Force Microscopy (EFM) is a promising tool for obtaining non-invasive subsurface images. However, little is understood about the electrical and spatial parameters in the imaging process. For this reason, in this work is developed a simulation model that allows defining the experimental parameters in the EFM technique such as: vertical resolution for detection, conductive tip voltage, separation between the surface of the polymer matrix and the tip and other parameters related to the dimensions of the polymer matrix based on Polymethylmethacrylate (PMMA). The analysis of this parameters allows the correlation with the capabilities of the EFM technique for detecting the depth of the CNTs and to identify the best conditions for both the polymer matrix and EFM before conducting laboratory experiments.

Resume : The properties of graphite, and of few-layer graphene, can be strongly influenced by the edge structure of the graphene planes, but there is still much that we do not understand about the geometry and stability of these edges. We present a theoretical study of the “closed” edges of graphite crystals, motivated by recent high-resolution transmission electron microscopy work. We use computer simulations based on density functional theory to obtain surface energies, and rationalise and quantify the preference for the formation of multiple concentric loops at the edges. We also discuss possible mechanisms for the observed separation of the folded edges in the presence of an electric field. This effect can be used to engineer new carbon-based nanostructures with high porosity.

Resume : The recent interest in 2D materials and their applications in a large variety of fields is somehow limited by their vulnerability caused by interaction with the environment. In particular, graphene, the vanguard of these materials family, has been shown to be sensitive to thermal treatments in O2 in a relatively low temperature range (150-400°C). This feature can be exploited to obtain electronic population changes (doping), but can represent a weakness due to reduced charge mobility. Recent studies have highlighted that the origin of doping is the interaction of graphene with the substrate and the interstitial molecules. In particular, it has been revealed that both the activation energy of the doping process and its time dynamics are affected by different substrates, with a significant influence of their hydrophilic properties. In this study, we report the functionalization of several supporting SiO2/Si substrates with surface groups of different polarity in order to tune their hydrophilic character. The impact on O2-driven graphene thermal doping was experimentally estimated by Raman spectra and Atomic Force Microscopy. To further corroborate our results, we performed first principle calculations using Density Functional Theory. Herein, by functionalizing the silica surface with apolar groups, we have evaluated the adsorption efficiency of O2 on graphene and how the electronic properties of SiO2 surface affect the charge distribution of the system.

Resume : To control the magnetic-related phenomena of a medium with the help of applied voltage is a rapidly developing research field in modern magnetism. Voltage (V) control of magnetism, magneto-resistance, magnetic anisotropy, and magnetization in a ferromagnetic layer exchange-coupled to a nonmagnetic layer has recently been reported. However, to explore the origin of observed phenomena by directly studying the spin polarized density of states (DOSs) of these heterostructures is rare and necessary. Carbon (C) has also been considered as a potential material for future electronics application. Therefore, in this work, ferromagnetic metal Co/C heterostructures were fabricated for realization V controlled magnetism evidenced by optical magnetic circular dichroism (OMCD) measurements, which can measure the spin polarized DOSs directly. The in-situ x-ray absorption spectra (XAS) measurements with applied voltage has also been employed to clarify further the electronic structures and local structures of these elements in Co/C heterostructures. In such Co/C samples, a following sizeable OMCD effect was observed. One broad MCD signal (feature A) in low energy region was obtained, while the other (feature B) shows a peak in the high energy region while applied a magnetic field. Interestingly, the OMCD hysteresis loops reveal different behaviors. We propose that the broad MCD signal arises from the optical transitions between Co d orbitals or bands of metallic Co and the peak in high energy region could be related to Co/C interface. And the OMCD hysteresis loops can be reversibly controlled by applied V. The XAS measurements give important information about the charge accumulation at the Co/C interface. The charge accumulation will lead to change of the Fermi level and the coupling of Co/C, therefore, changing the OMCD hysteresis loops. These results would open new a perspective for C based spintronics application. References 1. Hua-Shu Hsu, Yen-Chen Chang, Jing-Ya Huang, Ya-Huei Huang, Yen-Fa Liao*, Jian-Shing Lee, Shih-Jye Sun, Yeong-Der Yao, “Manipulation of the magneto-optical properties of a Co/C heterostructure under an applied voltage.” Carbon 140, 10 (2018). The authors would like to thank the Ministry of Science and Technology of the Republic of China, Taiwan, for financially supporting this research under Contract No. MOST 107-2119-M-153 -001.

Resume : Graphene and other two dimensional (2D) materials have unique phenomena because of their ideal atomically-flat surface and their localized density of states at their edges. Indeed, their features reflect to electrochemical activities such as hydrogen evolution reaction, oxygen reduction reaction. On the other hand, it was argued that the basal plane on 2D materials did not show particularly high reactions in spite of their large surface area. Recently, it was confirmed by visualization of the electrochemical active sites on graphene by electrochemical microscopy, resulting that their edge sites behave more active than that at the edges (A. Kumatani et al., Adv. Sci. 2019.). It is therefore necessary to initiate their activities on the basal plane for high performance electrochemical applications. In this study, we have applied a local activation technique on graphene surface by introducing overpotential though a meniscus created by a nanopipette filled with electrolyte and a counter/reference electrode (Y. Takahasi, A. Kumatani et al., Nat. Commun. 2014.). After the process, hydrogen evolution active sites are initiated by scanning the nanopipette. Further, their active sites were recognized by electrocatalytic reaction imaging. It will lead 2D material surface design for energy harvesting application.

Resume : Electrochemical Interface Modification on Practical Carbon Anodes for More Efficient Sodium-ion Batteries Jun Zhang 1, 2, Wei Lv 2, Feiyu Kang 1, 2, Quan-Hong Yang 1, 2, 3 1Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, Shenzhen 518055, China. 2Shenzhen Key Laboratory for Graphene-based materials and Engineering Laboratory for Functionalized Carbon Materials, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China. 3Nanoyang Group, State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China. Sodium-ion batteries (SIBs) are reviving and flourishing during last decade, with great potential to be practically applied in large-scale energy storage market. However, the construction of a stable electrochemical interface between anode material and electrolyte is still the bottleneck restraining the development of SIBs, especially on most promising carbon anodes. The regulation and modification of the interfacial electrochemistry is critical to increase the energy density, columbic efficiency and long-term stability of carbon anodes for their practical application in SIBs. Recently, we found that ether-based electrolytes are unique to modifying electrochemical interface of carbon anodes and largely improve the initial coulombic efficiency (ICE) of high specific surface area carbons (HSSACs). Then, we proposed a simple but effective remedy of deactivating and shielding defects on carbon anodes by Al2O3 nanoclusters. As a result, not only the coulombic efficiency but also the stability and rate capability of HSSACs can be further enhanced. More importantly, we investigated that the energy barrier to charge transfer at the electrochemical interface is a reliable parameter to assess the intricate sodiation dynamics in various anode materials of SIBs including carbon materials, which could definitely guide the design of well-matched novel aprotic electrolytes for carbon anodes and accelerate the commercialization of carbon anodes in metal-ions rechargeable batteries. References: [1] J. Zhang, S. Zhang, W. Lv, Q.-H. Yang et. al., Energy Environ. Sci., 2017, 10, 370 [2] J. Zhang, S. Zhang, W. Lv, Q.-H. Yang et. al., Adv. Energy Mater., 2018, 8, 1801361 [3] Q. Lin†, J. Zhang†, S. Zhang, W. Lv, Q.-H. Yang et. al., Adv. Energy Mater., 2019, 9, 1803078 [4] K. Li†, J. Zhang†, W. Lv, Q.-H. Yang et. al., Nature Commun., 2019, 10, 725

Resume : Field-effect transistors based on graphene (GFET) find application in many fields, especially in biosensing, due to their high sensitivity [1]. The density of charge carriers in the GFET channel can be modulated easily by applying an appropriate potential to the gate [2]. Inkjet-printing technique permits the fabrication of these devices outside of the clean room, reducing the time and the costs of the fabrication process. In this work, an inkjet-printable graphene oxide (GO) ink is formulated and deposited by inkjet-printing on the channel of photolithographed transistors. Among different ways to reduce the printed GO into reduced graphene oxide (rGO), we developed an in-situ electrochemical approach [3]. The morphology of the printed rGO layer and its electrical characteristics when used as conductive channel in the electrolyte-gated transistor configuration, were investigated. A strongly marked Dirac point is observed on our transfer curves, as well as an ambipolar behavior, as previously described [2]. We show that the reduction degree of GO is an important parameter, as it affects the charge transport behavior allowing the electrochemical control of the charge carriers mobility and of the doping level [4]. Further, we show that the doping level can be additionally tuned by supramolecular assemblies of N-rich organic adsorbates on rGO. [1] Zhan, B. et al. Small, 10 (2014)4042 [2] Meric, I. et al. Nature, 3 (2008) 654 [3] Mativetsky, J.M. et al. J. Am. Chem. Soc. 133 (2011) 14320 [4] Vasilijević, S. et al. Carbon, (2019) submitted.

Resume : Conductive boron-doped diamond (BDD) is expected as a functional electrode material that can be used in various electrochemical applications because of its unique electrochemical properties such as wide potential window and low background current. In this study, we developed BDD powder (BDDP)-based electrodes to expand the application field of BDD electrode. As an application of BDDP to electrode material, we have developed BDDP-printed electrodes. An ink containing BDDP and polyester resin binder was printed on a polyimide substrate by screen printing to obtain a BDDP-printed electrode. The BDDP printed electrodes showed lower background current and larger signal-to-background ratio in the electrochemical detection of some analytes than conventional carbon-printed electrodes as well as BDD thin film electrodes. Thus, the BDDP-printed electrode is expected to be used as an inexpensive, disposable and sensitive electrochemical platform. In addition, we investigated the electrochemical properties of BDDP toward application to aqueous electric double-layer capacitor (EDLC). CV in 1.0 M H2SO4 recorded in a symmetric two-electrode system with BDDP electrodes showed a cell voltage of 1.5 V, which was much greater than with activated carbon (0.8 V). In addition, when using boron-doped nanodiamond (BDND) with large specific surface area, the energy and power density in the aqueous electrolyte was greater than when using activated carbon. Therefore, it was suggested that the conductive diamond particles are useful as an electrode material for aqueous EDLCs exhibiting both high energy and power density.

Resume : The low-dimensional modifications of carbon like nanodiamonds, graphene, fullerenes and nanotubes present a particular interest for the developing fields of nano- and optoelectronics. The studies of one-dimensional chained materials remain undervalued due to the limitations of the synthesis techniques, especially those for free-standing carbyne. Many methods of carbyne synthesis have been proposed but resulted in amorphous or poorly ordered films/powders with crystallite size less than 100 nm. In order to improve the synthesis procedure, we use the Optically Stimulated Electron Spectroscopy (OSEE) and Ambient Pressure Photoemission Spectroscopy (APS) methods along with DFT modeling, which allow us to assess the quality and photoemission parameters of the coatings containing carbon chains. Raman measurements are performed to control the changes in bonding and atomic structure of the chained films. Photoemission results reveal a thermodynamic and photoelectric threshold values around 4.8 eV and 5.0 eV, respectively. Electron emission intensity depends on film thickness, while average work function difference reflects the changes in carbyne-containing film morphology. In view of the lack of rapid and comprehensive technique for characterization of linear-chained carbon and carbyne-containing nanocomposites the search for new methods is of great importance. Electron emission in atmospheric conditions (APS) proves to be a capable tool for assessment of carbon coating thickness, while emission in vacuum reveals its morphology. In combination with Raman spectroscopy these techniques could be used for characterization of composite coatings containing carbon chains.

Resume : The fabrication of a sandwich-like composite that consists of reduced graphene oxide (RGO) and Si3N4 ceramic (RGO/Si3N4) was achieved through the combination of modified freeze-drying approach and chemical vapor infiltration (CVI) process. Due to a hierarchical structure and high ratio of ID/IG (1.27), the RGO/Si3N4 exhibits an unprecedented high polarization relaxation loss (PRL), which accounts for 32 % of the whole dielectric loss. The outstanding PRL endow the RGO/Si3N4 composites with unique temperature-independent dielectric properties and electromagnetic (EM) wave absorption performance. Even at a low absorbent content of only 0.16 wt.%, the effective absorption bandwidth of RGO/Si3N4 composite can cover the whole X-band (8.2~12.4 GHz) at broad sample thicknesses and temperatures range from 4.3 mm to 4.6 mm, and 323 K to 873 K. The mechanism for the enhancement of polarization relaxation loss and conductive loss was explicitly investigated. The outstanding absorption performance toward EM wave indicated the resultant porous RGO/Si3N4 composite can be a promising candidate for the applications under elevated temperature.

Resume : We report the deposition of minute amount (less than a monolayer) of transition metals (TM = Fe, Co, Ni) on ta-C films prepared by pulsed laser ablation (PLD) on transparent quartz (TM/ta-C/quartz sample). Apart from the nature and dose of metal evaporated, the thickness and the sp3/sp2 ratio controlled by the PLD parameters (time and fluence) are key parameters investigated in order to grow by thermocatalytic treatments a thin graphitic layer from ta-C (1). The formation of the thin graphitic layer is depending both on time (2), temperature and gas environment. The location of the metallic nanoparticles was investigated by XPS while the formation of graphitic domains was investigated by Raman spectroscopy. The choice of the transition metals has been operated as a function of their high reactivity to carbon-carbon bond reactivity but also to their ability to absorb carbon. The system TM/thin graphitic layer/DLC/quartz exhibits under optimized conditions, high transmission and high surface conductance, with figures of merit for transparent conductivity higher than ITO. We observed an optimum in the fluence as well as the thickness of the DLC layer. (1)“High performance diamond-like carbon layers obtained by pulsed laser deposition for conductive electrode applications, F. Stock, F. Antoni, F. Le Normand, D. Muller, A. Abdesselam, N. Boubiche and I. Komissarov, Applied Physics A: Materials Science & Processing - 'New Frontiers in Laser Interaction', 123 (2017) 590-595 (2)“Kinetics of graphitization of thin diamond-like carbon (DLC) films catalyzed by transition metal” N. Boubiche, J. El Hamouchi, J. Hulik, M. Abdesslam, C. Speisser, F. Djeffal and F. Le Normand, Diamond and Related Materials, 91 (2019) 190-198

Resume : Carbon can form crystalline graphite under a certain high temperature environment. The graphitization degree can be increased by increasing the temperature, changing the temperature rise rate, or extending the retention time of the graphitization reaction section of carbon, and different electric conduction and electromagnetic wave attenuation capacities can be formed. The continuous laser ablative carbonization experiment of epoxy resin-based quartz fiber reinforced composite materials is carried out under the same incident laser energy. The experimental results show that the dielectric constant increases significantly in the range of 7GHz to 17GHz compared with the initial state. The Fourier transform infrared spectrum (FTIR), XRD test results and surface scanning electron microscopy images of the ablative products on the surface of the sample show that the thermal decomposition, pyrolysis and other changes of the epoxy resin occur under laser irradiation, and the graphitized carbon of island chain formed in situ on the surface of the material is the cause of dielectric constant increase. Under the condition of power density of 226W/cm2，and irradiation time of 10s, due to the long time of high temperature environment generated by laser action, the graphitization degree of carbon black is larger, and the dielectric constant of the material increases the most. At the same time, the rough surface state and loose state caused by laser ablation increase the reflection of electromagnetic wave.

Resume : High-performance carbon nanotubes (CNTs) with adjustable electro-conductivity have been widely used as electromagnetic (EM) waves absorption materials to achieve stealth of weapons and equipment. Chemical vapor deposition technology is used for the simple preparation of CNTs on porous Sc2Si2O7 matrix. As expected, well-matched impedance and EM dissipation of CNTs/Sc2Si2O7 ceramics are synthesized. Curls of CNTs formed a three-dimensional network structure and large amounts of interfaces, resulting in multiple reflections and scattering of EM waves. The defect concentrations can be optimized by tuning reaction times. The existing defects will produce dipole polarization and affect the band gap of CNTs as well. Using density functional theory as first principle calculations, we calculate and simulate the relationship between band gap and vacancy-defects of CNTs. The results show that the appropriate contents of vacancy-defects will increase the band gap of CNTs, which regulate the conductivity loss of CNTs/Sc2Si2O7. Hence, the excellent microwave absorption performance of CNTs/Sc2Si2O7 (loading content of 1.56 wt.%) is RCmin of -33.5 dB at the thickness of 2.85 mm, achieving an effective absorbing bandwidth of 4.2 GHz covering the whole X-band. The exploration results provide a useful reference to EM wave absorption materials with strong absorption, wide bandwidth and thin thickness.

Resume : Degradation efficiency of the catalysts is of primary concern for photoelectrochemical (PEC) processes. Namely, the catalysts featuring excellent charge separation and transfer, as well as high photoelectrochemical performance are needed. In this presentation, we show the fabrication process of a new catalyst based on TiO2 and Boron-Doped Diamond (BDD) patterns. The TiO2/BDD patterns possess a rutile n-type TiO2 film with uniform p-type diamond exposed area (40 μm× 5 μm rounded rectangle patterns). A photolithography method was utilized for the construction of such patterns. The as-prepared TiO2/BDD patterns were characterized using SEM, XRD, and XPS. The electrochemical (EC) performance and PEC performance of the as-prepared patterns were evaluated and further compared with a BDD film and a TiO2 coated BDD film. The achieved TiO2/BDD patterns, integrated EC and PEC activities, successfully display co-catalysis activity in the condition with bias potential and UV irradiation.

Resume : Carbon nanotubes and graphene can show excellent light absorbing ability on near-infrared laser irradiation. Using the photothermal properties of the graphene, photo-responsive actuators can be fabricated with the shape memory polymers. To achieve high performance photo-actuators, enhanced interaction between polymer and graphene is needed. In this study, epoxy-functionalized graphene oxide (epoxy-GO) was synthesized and used to fabricate photo-actuators of epoxy-functionalized GO, epoxy and hyperbranched polyurethane (HBPU). The HBPU was synthesized using poly(ε-caprolactone) as the soft segments, and epoxy-f-GO was obtained from a reaction of GO and bisphenol A diglycidyl ether. The covalently bonded functionalization of GO with epoxy group was confirmed and the surface morphology of the composites was observed with TEM measuremetns. Photo-responsive shape recovery actuation of composites was evaluated by irradiating the near infrared laser on the composites. The composites showed good photo-actuation stress and enhanced mechanical properties. The results indicate that the epoxy-f-GO is very effective to fabricate the laser-driven remote-controllable photo-actuator.

Resume : Pressure-retarded membrane distillation (PRMD) is an emerging membrane process to recover energy from low-grade heat sources. The applied hydraulic pressure on the cold-water side in PRMD may strongly affect both energy conversion efficiency and membrane performance. Here, we report the first systematic study on this critical issue. A commercial nanoporous polytetrafluoroethylene membrane was evaluated as a general membrane sample over a range of applied pressures from 0 to 10 bar at a temperature difference of 40 °C. Our results show that the theoretically projected constant water vapor flux decreases significantly with the increase of the applied pressures, which can be attributed to the severe membrane deformation induced by pressures. The membrane in the active-layer-facing-hot-solution orientation is mechanically unstable with the complete loss of water vapor flux under 2 bar. In contrast, the membrane in the active-layer-facing-cold-solution orientation can still work under 10 bar. Combining theoretical analysis and detailed characterization of membrane physical structures, we show that the properties of membrane active layers (i.e., pore size, porosity, and thickness) deteriorate under elevated pressures. Deformed membranes have lower permeability and higher temperature polarization in PRMD, resulting in the observed lower water vapor fluxes. Our results suggest that improving the mechanical stability of membranes would be the first critical step in realizing practical applications of PRMD for low-grade heat recovery. Potential research directions for developing novel PRMD membranes are also proposed.

Resume : Nanodiamonds have a variety of, mainly oxygen-containing, functional groups on the surface and that makes it complicated to control surface chemistry. Many efforts were made so far to uniform, or reset, surface chemistry such as hydrogenation, carboxylation, hydroxylation, graphitization, and so on. As each modification method gives different surface charge and other properties, different condition should be applied to give dispersion of each modified nanodiamonds. We prepared single-digit nanosized water dispersion of vacuum-annealed, graphitized detonation nanodiamonds using bead-milling. We will report and discuss some adsorption properties of the dispersion as well as dispersion condition.

Resume : Carbon molecular sieve (CMS) membrane is the promising candidate to separate olefin/paraffin due to its molecular sieving separation property into rigid slit-like pore, which can surpass the upper bound and plasticization problem of polymeric membranes. In this study, CMS hollow fiber composite membrane was prepared by pyrolysis/carbonization process of polyimide polymer precursor onto alumina hollow fiber support. This membrane could separate propylene/propane mixture gas into propylene-rich product of more than 20-fold compared with feed gas. On the other hand, recently, we found out that the significant reduction of gas permeance during a long-term stability test of CMS membrane, attributing to physical packing of imperfect graphene-like layers at the early stage after carbonization. The loss of gas permeance was accelerated at higher operating pressure. This loss was not even recovered through regeneration process at the temperature of 300 oC under hydrogen/argon feed gas to compensate the initial performance. Herein, in order to prevent the physical aging in CMS membrane, the pre-crosslinking reaction of polyimide precursor prior to pyrolysis was employed. Surprisingly, the pre-crosslinking was effectively affected on the mitigation of aging in CMS membrane. This work was supported by the National Research Council of Science & Technology (NST) of the Korea government (No. CRC-14-1-KRICT).

Resume : Intense pulsed light (IPL) using a Xenon flash lamp with a broad wavelength spectrum is a technology used mainly in sintering of metal particle-based electrodes for printed electronics. One of the key points in the IPL sintering process is to maximize the light absorption of printed metal-based electrodes, because photo sintering efficiency is considerably related to the surface plasmon polariton which is resulted from coupling of surface plasmons with light. In this regard, oxide-free, small sized metal particles are a prerequisite, but the production cost should be increased. In this paper, we propose a “Bidirectional photo-sintering system” in which the light is irradiated on both front and back side by providing a reflector. Furthermore, we introduce the metal particle/graphene-core/shell structure to increase the light absorption as well as the sintering efficiency. The photo-sintered metal/graphene electrodes using bidirectional IPL show better electrical, mechanical properties, and environmental reliabilities compared to conventional IPL.

Resume : Resume : We have prepared various all-organic magnetic soft materials containing a cyclic nitroxide radical moiety as a spin source [1]. In this talk, we report the preparation of all-organic magnetic nanoemulsions composed of the non-ionic surfactant and the hydrophobic nitroxide radical compound [2]. The properties of the nanoemulsions have been investigated by small angle neutron scattering (SANS) and dynamic light scattering (DLS) analyses, EPR spectroscopy, and MRI method. The nanoemulsions showed high colloidal stability, high reduction resistance to ascorbic acid, low cytotoxicity and an enough contrast enhancement in the proton longitudinal relaxation time (T1)-weighted MR images in (-)-PBS in vitro and in vivo. Furthermore, an additional hydrophobic anticancer drug such as Taxol® was simultaneously encapsulated inside the nanoemulsions. We expect that the drug-loaded nanoemulsions can be used as a biocompatible magnetic drug carrier for MRI-visible targeted delivery system. [1] a) Uchida, Y.et al. J. Mater. Chem. 2009, 19, 6877; b) Uchida, Y. et al. J. Am. Chem. Soc. 2010, 132, 9746; c) Takemoto, Y. et al. Soft Matter 2015, 11, 5563 [2] K. Nagura, N. Komatsu, R. Tamura, et al., Chem. Eur. J., 23, 15713 (2017); K. Nagura, N. Komatsu, R. Tamura, et al., Nanotechnology, 30, 224002 (2019); K. Nagura, N. Komatsu, R. Tamura, et al., Pharmaceutics, 11, 42 (2019).

Resume : Since thin layer 2D materials have been attracting enormous interest, various processes have been investigated so far to obtain these materials efficiently. In view of their practical applications, the most desirable source is the pristine bulk material with stacked layers such as pristine graphite. On their exfoliation, we have many options in terms of conditions such as wet or dry, with or without additive, and kind of solvent. In this context, we have found versatile exfoliant, 2,3,6,7,10,11-hexahydroxytriphenylane, which works efficiently for exfoliation of typical 2D materials, graphene, MoS2, and h-BN, in both wet and dry processes using sonication and ball-milling, respectively, in aqueous and organic solvents [1,2]. As for graphene, stable dispersions with relatively high concentration (up to 0.28 mg/mL) in water and tetrahydrofuran were obtained from graphite in presence of hexahydroxytriphenylene by wet process using bath sonication and via dry process using ball-milling. Especially, most of graphite was exfoliated and dispersed as thin layer graphene in both aqueous and organic solvents through ball-milling even at large scale (47 - 86% yield). In addition, the exfoliant can be easily removed from the precipitated composite by heat treatment without disturbing the graphene structure. Bulk MoS2 and h-BN were also exfoliated in both wet and dry processes. As in graphene, MoS2 and h-BN dispersions of high concentrations in water and DMF were produced in high yields through ball-milling. [1] G. Liu, N. Komatsu* ChemNanoMat, 2 (6), 500 - 503 (2016) [highlighted at the front cover]. [2] G. Liu, N. Komatsu* ChemPhysChem, 17 (11), 1557?1567 (2016) [highlighted at the front cover].

Resume : In this paper, we report simple, scalable and high-yield production of MoS2 and WS2 nanosheets through solid phase exfoliation using ball milling in the presence of sodium cholate (SC) [1]. The exfoliated MoS2 and WS2 nanosheets are stored as ?stock solid? and readily dispersed in water simply by shaking with hand prior to use. While solid phase exfoliation using ball milling has been applied to the production of graphene nanosheets, this methodology has not been demonstrated in the exfoliation of TMDs such as MoS2 and WS2. Although we have reported scalable method using hexahydroxytriphenylene as an exfoliant through ball milling, bath sonication for half an hour has been required to obtain stable dispersion [2]. As compared with wet-grinding and liquid phase ball milling, the dry process reported here is considered to be more preferable to keep the solid as it is for longer time, because the presence of liquid may facilitate aggregation as mentioned above. In addition, simple dispersion with controlled concentration can be prepared from the dry ball milled solid, while the liquid used for exfoliation under wet conditions may make solvent system complicate, and concentration less precise and less controllable. First, the effect of surfactant amount in the ball milling process was studied; the amount of MoS2 was fixed at 0.20 g and the amount of SC was varied from 0.010 to 0.40 g. The powder obtained after ball milling was dispersed in deionized water (100 mL) and the resulting dark-greenish suspension was centrifuged at 3000 rpm (1025g) for 60 min. The top 75% of the supernatant was subjected to UV/vis spectroscopic analysis. The yield (%), the mean number of layers, and lengths of the napnosheets can bewere calculated estimated using the extinction and the reported coefficient at 345 nmreporte, the wavelength of the exciton peak (A), and the ratio of the extinction at 605 nm and 345 nm (Ext605/Ext345), respectivelyof MoS2 in the dispersion was calculated by the extinction at 345 nm and the extinction coefficient reported. The yield of MoS2 increased according to the increase of the weight ratio of SC/MoS2. The yield of 9% obtained at the SC/MoS2 weight ratio of 2 is much larger than that obtained by liquid phase sonication. The yield of MoS2 saturated around 0.40 g of SC. In addition, the mean number of layers and lengths of nanosheets can be estimated using the wavelength of the exciton peak at 658 (A) and Ext605/Ext345 ratio, respectively. The morphology of MoS2 nanosheets was determined to be two layers and 60 - 80 nm in size, from the A of MoS2 observed at 658 nm and the value of Ext605/Ext345. [1] G. Liu, N. Komatsu* ChemNanoMat, 2 (6), 500 - 503 (2016) [highlighted at the front cover]. [2] G. Liu, N. Komatsu* ChemPhysChem, 17 (11), 1557?1567 (2016) [highlighted at the front cover].

Resume : Nanodiamonds (NDs) have excellent mechanical and optical properties, large surface areas and tunable surface structures. They were found to be relatively less toxic among nanoparticles, making them well suited to biomedical applications [1]. In order to enhance the intrinsic properties and append new properties, hybridization of NDs with other nanoparticles seems promising technique. However, most of the related work towards such fundamental hybridization is limited to top-down lithography which is typically a very complicated and time-consuming process, and is difficult to be scaled up. Here, we develop a facile bottom-up synthetic approach to prepare ND-superparamagnetic iron oxide nanoparticle (SPION) nanohybrid using solvothermal method and investigate its magnetic resonance imaging (MRI) contrast ability and heat generation property in alternating magnetic field. To prepare ND-SPION particles, first, ND with 50 nm and 100 nm sizes (ND50 and ND100, respectively) were covalently functionalized with hyperbranched polyglycerol (PG) according to the procedure we reported previously [2]. Then, appropriate amount of ND-PG (5.0 mg of NDs) mixed with iron acetylacetone (Fe(acac)3, 13.5 or 31.5 mg) in triethylene glycol (30 mL) to prepare ND:SPION (70:30) or ND:SPION (50:50), respectively. Finally, the mixture was heated up to 230 °C in a 60 mL autoclave and kept at the temperature for 1 h. A transmission electron microscopy (TEM) image shows ND50-SPION in which SPION are hybridized on the surface of ND50. Inset Furthermore, the both X-ray diffraction (XRD) peaks of SPION and ND were confirmed in NDs-SPION nanohybride. Dynamic light scattering measurements in water indicated that hydrodynamic size of ND50-PG and ND100-PG increased from 78 and 120 nm to 135 and 170 nm for ND50-SPION (50:50) and ND100-SPION (50:50), respectively. As for the physical properties, their MRI contrast ability is found to improve from 210 mM-1s-1 for pure SPION to 330 mM-1s-1 for ND50-SPION (50:50) at r2 relaxivity. ND100-SPION (50:50) raised temperature of ??? twice faster compared to pure SPION in alternating magnetic filed. We believe that our button-up synthetic strategy can be applied to hybridize various kind of nanoperticles on the ND surface. [1] Choy, J. T. et al. Nat. Photonics 5, 738 (2011). [2] N. Komatsu, et al. Adv. Funct. Mat. 24, 5348 (2014).

Resume : Diamond color centers are chemically stable fluorescent defect. Since their fluorescence doesn’t indicate photo-beaching or blinking unlike organic dyes, they have been expected to serve as a probe of bio-imaging. Silicon vacancy (SiV) center is one of those color centers, which indicates the sharp photo luminescence (PL) spectrum at near-infrared region (738 nm). This feature will make it possible to externally excite and detect fluorescence of defect-containing diamond delivered inside living tissues. SiV center can be fabricated by silicon ion implantation into high-purity IIa type diamond. Also, there have been reports that SiV center was introduced in diamond thin film by chemical vapor deposition (CVD) on Si substrate. Concentration of SiV center by those methods, however, was not enough for bio-imaging application. We explored and found the method to introduce SiV center in high concentrations. First, polycrystalline diamond thin film containing Si atoms was made by CVD method on Si substrate. Second, high energy beam such as helium ion was irradiated just to introduce vacancies at appropriate concentration. Then annealing was performed to form SiV center. Diamond nanoparticles containing SiV center should be obtained by disintegration of the polycrystalline diamond thin film using conventional procedure such as bead-milling.

Resume : For several decades, industrial processes consume a huge amount of raw water for various objects that consequently results in the generation of large amounts of wastewater. There effluents are mainly treated by conventional technologies such are aerobic, anaerobic treatment and chemical coagulation. But, there processes are not suitable for eliminating all hazardous chemical compounds form wastewater and generate a large amount of toxic sludge. Therefore, other processes have been studied and applied together with these techniques to enhance purification results. These techniques include photocatalysis, absorption, advanced oxidation processes, and ozonation, but also have their own drawbacks. In recent years, electrochemical techniques have received attention as wastewater treatment process that show higher purification results and low toxic sludge. There are many kinds of electrode materials for electrochemical process, among them, boron doped diamond (BDD) attracts attention due to good chemical and electrochemical stability, long lifetime and wide potential window that necessary properties for anode electrode. So, there are many researches about high quality BDD, among them, researches are focused BDD on Si substrate [4]. But, Si substrate is hard to apply electrode application due to the brittleness and low life time. And other substrates are also not suitable for wastewater treatment electrode due to high cost. To solve these problems, Ti has been candidate as substrate in consideration of cost and properties. But there are critical issues about adhesion that must be overcome to apply Ti as substrate. In this study, to overcome this problem, TiN interlayer is introduced between BDD and Ti substrate. TiN has higher electrical and thermal conductivity, melting point, and similar crystalline structure with diamond. The TiN interlayer was deposited by reactive DC magnetron sputtering (DCMS) with thickness of 50 nm, 1 µm. The microstructure of BDD films with TiN interlayer were estimated by FE-SEM and XRD. There are no significant differences in surface grain size despite of various interlayer. In wastewater treatment results, the BDD electrode with TiN (50nm) showed the highest electrolysis speed at livestock wastewater treatment experiments. It is thought to be that TiN with thickness of 50 nm successfully suppressed formation of TiC that harmful to adhesion. And TiN with thickness of 1 µm cannot suppress TiC formation.

Resume : Carbon spiroids [1] are the relatively new and one of the least studied carbon allotropes. They are good candidates for the nanocpacitors[2], hydrogen storage [3] and in catalysis due to the unique open structure. Electron beam-induced structural transformations of carbon nanostructures were an interesting topic for the few last decades [3,4]. We've chosen carbon spiroids C300 [3] and C209 [4] as the model objects and applied the the framework of ab-initio approach implied in the Gaussian program package[5]. We found that due to the relatively small amount of atoms in the studied nanoparticles the excess charge causes the significant structural change: the interatomic bonds diagram demonstrates the increase of the sp3/sp2 bonds ratio and corresponds well with the experimental results [3]. We acknowledge the computational grant G60-8 from the Interdisciplinary Center for Mathematical and Computational Modelling(ICM) in Warsaw. References 1. M. Ozawa, H. Goto, M. Kusunoki, E. Osawa, J. Phys. Chem. B. 106, 7135–7138 (2002) 2. M. Zeiger, N. Jackel, V. N. Mochalin 1. and V. Presser, J. Mater. Chem. A, 2016, 4, 3172–3196. 3. Yastrebov, M. Chekulaev, A. Siklitskaya, J. A. Majewski, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 393 (2017) 3.F. Banhart & P. M. Ajayan, Naturevolume 382, pages 433–435 (1996) 4.Lin Lai and Amanda S. Barnard, J. Mater. Chem., 22, 13141-13147 (2012) 4. S.G. Yastrebov, R. Smith, A.V. Siklitskaya, Mont. Not. R. Astron. Soc. 409 (2010) 1577 5. M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria,M. A. Robb et.al. “Gaussian 09, Revision B.01,” 2009.

Resume : The increasing interest in biosensing and early diseases’ diagnosis has led to remarkable efforts in finding suitable materials and sensing mechanisms to achieve high sensitivity and selectivity at low production cost. Among the most investigated materials, metal oxides like zinc oxide (ZnO) and carbon-based materials have been playing an important role in the field due to their versatility and unique properties, namely their biochemical stability, biocompatibility and functionalisation simplicity. As such, the synergetic combination of these materials should result in advanced functional properties, which can be tailored to the desired application. In this framework, we report the development of ZnO/laser-induced graphene (LIG) composites by direct laser writing in a single processing step. We aim at using these composites as transducer platforms in the fabrication of optical and electrochemical devices for detection of biomedical analytes. In this approach, a polyimide polymer covered with a ZnO precursor is irradiated with a CO2 infrared laser under ambient conditions, producing a graphene foam with ZnO crystals. The simultaneous production of both components is expected to lead to a strong materials interconnection. Other advantages of this method include the production of flexible samples, a prompt synthesis process, easily scalable and the ability to perform patterned designs by using a computer-assisted laser-scribing system. The produced composites were fully characterised by electron microscopy, Raman and photoluminescence (PL) spectroscopies, as well as electrochemical analysis. The combination of laser processing conditions chosen for each sample was seen to have a noteworthy influence in the composite’s properties. Furthermore, tests monitoring the PL outcome as a function of the concentration of the human chorionic gonadotropin (hCG) hormone suggested their promising application in the production of biosensors with clinical interest.

Resume : Electrocatalytic oxidation of liquid fuels needs catalyst support with large areas and highly active metal catalysts. In this presentation, we show the utilization of expanded graphite, multi-walled carbon nanotubes, and graphene as the catalyst supports and their further application to load electrochemically or wet-chemically metal catalysts, including palladium nanoparticles, platinum nanoparticles, and palladium/platinum nanoparticles. The characterization of these nanocomposites using electron microscopy, X-ray techniques, and electrochemical methods will be shown. The optimization of the compositions, more exactly the mass ratios of nanocarbons to metal nanoparticles will be conducted through the investigation their electrochemical activity and double-layer capacitances of the nanocomposites. The results about electrocatalytic oxidation of short carbon-chained alcohols (namely methanol, ethanol, ethylene glycol), carboxylic acids (namely formic acid), and aldehydes (namely formaldehyde) in alkaline media will be detailed. On the nanocomposite of Pd nanoparticles and expanded graphite, the oxidation currents of these liquids are stable and in the order of formaldehyde > formic acid > glycol > methanol > ethanol. The oxidation occurs in two steps: the oxidation of freshly chemisorbed species in the forward scan and then in the reverse scan the oxidation of the incompletely oxidized carbonaceous species formed during the course of the forward scan. These electrocatalysts are thus useful for the facilitation of direct methanol fuel cells.

Resume : An electrochemical interface with a large surface area and a big amount of active sites are promising for sensitive, selective, and reproducible monitoring of multiple phenols simultaneously. In this presentation, expanded graphite (EG) supporter is decorated with the sensing material of carbon-coated palladium oxide (PdO@C) nanoparticles. Its characterization conducted using transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical techniques will be shown. Then, the utilization of this composite based electrochemical interface for the voltammetric sensing of tetrabromobisphenol A (TBBPA), hydroquinone (HQ), and catechol (CC) will be summarized. Compared with either EG or PdO@C based interfaces, this one delivers much enhanced redox currents for three phenols. In more detail, individual and simultaneous detection of TBBPA, HQ, and CC has been realized at nano-molar levels. The calculated detection limits are 1.3, 26, and 17 nM for TBBPA, HQ, and CC, respectively. Such an interface thus owns great prospect in constructing a universal platform for individual and simultaneous detection of multiple phenols in different samples.

Resume : Nanocarbons like graphene, carbon nanotubes, and expanded graphite feature different morphology and surface functional groups. They are thus expected to have different sensing applications. In this presentation, several nanocarbons including graphene nano platelets (GNPs), multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), aminated graphene (NH2-G), expanded graphite (EG) have been utilized for sensing soluble species with different charges. Prior to showing these results, electrochemical response of redox electrolytes on these nanocarbons will be presented. For example, reversible and diffusion-controlled electrode processes for faradaic reactions of Fe(CN)63-/4- are seen on all these nanocarbons. The capacitive current of MWCNTs is the biggest, while that of GO is the smallest. Voltammetric response of positively and negatively charged inorganic ions (Pb2+, NO2−) as well as neutral organic colorants (sunset yellow and tartrazine) will be shown in detail. The sensitive monitoring of three species on different nanocarbons or composites will be summarized.

Resume : The acetone level in diabetic patients is double compared to healthy people, and is important not only for biosensors but also for gas sensors. In this study, acetone detection is performed using an environmentally friendly method. CNWs were grown on the substrate using a microwave plasma enhanced chemical vapor deposition (MPECVD) system with a mixture of methane (CH4) and hydrogen (H2) gases. And then, aluminum-doped zinc oxide (AZO) and zinc oxide(ZnO) was deposited on CNWs using an RF magnetron sputtering system with 4-inch target of AZO and ZnO. The surface structure of AZO / CNW and ZnO / CNW were confirmed through Raman spectroscope and FE-SEM (Field Emission Scanning Electron Microscope). The electrical characteristics of samples were analyzed by Hall measurement. The detection characteristics of between the sample and acetone were confirmed according to temperature using current multimeter. A voltage of 200 mV was applied to the electrode corresponding to the source and the drain of the sample, and the organic matter such as acetone, methanol and ethanol were evaporated to confirm the electrical change of samples by sensing the evaporated organic gas.

Resume : The interface between graphene overlayers and metallic substrates is a potential system for trapping small molecules of environmental importance. The well-defined limited space can provide microenvironments for confined catalysis, with stabilization of active sites. We studied in particular the carbon monoxide intercalation at the Graphene/Ni(111) interface by combining extensive density functional theory (DFT) calculations with a multi-technique experimental characterization by STM, LEED and XPS. We characterize the structure of the intercalated layer and the carbon monoxide adsorption sites with the substrate. The CO intercalation causes the detachment of the graphene overlayer, which recovers the peculiar electronic properties of the free-standing configuration. The Authors acknowledge support from the University of Trieste (Project FRA 2018) and from the Italian Ministry of Foreign Affairs and International Cooperation (Project PGR00795).

Resume : Carbon nanomaterials (and especially carbon nanotubes) are often cited first when people are asked about "nanoparticles" in general. For some people, they represent a huge potential of applications due to their extraordinary properties (or more realistically because of their unique combination of different properties), while some others will mention first the (potential) related toxicity issues. We will quickly review different aspects related to the potential environmental toxicity of carbon nanomaterials and will summarize our main results in this field, obtained using different in vivo models (amphibians, algae). In particular, we have recently identified that the impact of carbon nanomaterials with very different morphologies ranging from zero-D (nanodiamonds) to 2D (few-layer graphene, graphene oxide) can be generalized when the metric used for the comparison of the data is the surface (m²/L) instead of the weight (g/L) [1]. Finally, we will see in the specific case of graphene oxide how the modification of surface chemistry (reduction) can be used to significantly decrease the risk during handling and use, in the framework of a "safer(r) by design" strategy [2]. References: [1] A. Mottier, F. Mouchet, C. Laplanche, S. Cadarsi, L. Lagier, J-C. Arnault, H. Girard, V. Léon, E. Vazquez, C. Sarrieu, E. Pinelli, L. Gauthier, E. Flahaut, Nano Letters, 16 (6), (2016), 3514-3518, "Surface area of carbon nanoparticle: a dose-metric for a more realistic ecotoxicological assessment" [2] L. Evariste, L. Lagier, P. Gonzalez, A. Mottier, F. Mouchet, S. Cadarsi, P. Lonchambon, G. Daffe, G. Chimowa, C. Sarrieu, A-M. Galibert, C. Matei Ghimbeu, E. Pinelli, E. Flahaut, L. Gauthier Nanomaterials, 9, (2019), 584:1-16, "Thermal reduction of Graphene Oxide mitigates its in vivo genotoxicity toward Xenopus laevis tadpoles"

Resume : Due to increasing global energy demands, environmental pollution, and the rapid development of self-powered devices, converting ubiquitous environmental energy to usable energy, e.g., electricity is attracting increasing interests worldwide. Over the past decade, a number of studies have confirmed that power generation from the interactions of water molecules with nanostructured carbon materials is possible. Herein, a type of porous graphene oxide (GO) sponges is fabricated using the freeze-drying method. Then an annealing treatment and UV/Ozone oxidation are carried out to achieve partially reduced GO (rGO) sponges. We find that these rGO sponges can convert environmental energy to electricity via the natural evaporation of water. The generated open-circuit voltages are measured to be as high as about 0.63 V over a single piece of rGO sponges. The maximum output power and output power density are calculated to be approximately 17.30 uW and 1.74 uW cm-2, respectively. We suggest that streaming potentials, which arise from water molecule-graphene interactions, should be the underlying mechanism of water-evaporation-induced electricity generation. Furthermore, we demonstrate that ambient temperatures, airflow velocities, and evaporation-areas all can seriously influence the electricity generation. Moreover, the water-evaporation-induced voltage can be easily scaled up to as high as about 2.34 V by connecting multiple samples in series. Therefore, our work supplies a potential method of converting ubiquitous environmental energy to electricity.

Resume : Access to safe and sufficient water is essential to the development of human communities. Water quality assessment is crucial for the detection of waterborne pathogens, such as E. coli. These bacteria pose a major health risk, especially in developing countries where a lack of cost-effective and easy-to-use tools makes water quality diagnosis difficult. Paper-based sensors provide inexpensive and sustainable platforms for fabrication of simple, portable and disposable tools for environmental monitoring, in particular, in resource-limited surroundings. These paper-based sensing platforms benefit from the porous nature of the paper and offer compatibility with electrochemical detection since electrodes can be easily defined on paper by a variety of printing techniques. We rely on a common inkjet printer for the rapid and low-cost fabrication of sensing electrodes on paper. Commercially available, aqueous, conductive inks containing carbon nanotubes were used to illustrate the feasibility of paper-printed electronics for water constituent diagnostics. Our approach provides a reliable path in exploring the sensing characteristics of such devices. First, the electrode properties can simply be controlled by the printing parameters. For instance, conductivity can be adjusted with the number of prints. Twenty prints are required for a sheet resistance of 10 kΩ/□. Second, the dielectric properties are tuned via the type of paper employed as well as the printed geometry. We evaluated the impedance response of the inkjet-printed sensing devices at various concentrations of sodium chloride diluted in water. These sensors can support low-cost and decentralized quantitative water analysis with a minimal environmental footprint.

Resume : Laser scribing has been proposed as a method for transforming polymers or graphene oxide into graphene. Such materials were then used for applications in sensing and electronics. Here, we investigate laser modification of polyimide and graphene oxide both in air and in controlled atmosphere, including inert and reactive. The degree of conversion was investigated against different irradiation conditions by Raman spectroscopy. The as obtained materials was further functionalized by metal nanoparticles. We built a sensor array using a range of materials obtained under different atmospheres and with different functionalizations. The sensing behavior of such arrays was investigated towards humidity as well as common organic solvents like ethanol, acetone, chloroform, hexane, toluene, etc. and the response investigated by multivariated analysis.

Resume : A high-performance supercapacitor (SC) features a big and stable capacitance, high power and energy densities. To construct such SC, the applied capacitor electrode and used electrolyte play key roles. For example, a free-standing film is better than power based electrode since the addition of organic binders and the use of current collectors make the fabrication of the capacitor electrode more complicated and reduced capacitance performance. In this presentation, we show the applications of binder- and current-collector-free films as the capacitor electrodes to construct high performance supercapacitors. These films are grown using chemical vapour deposition techniques. For example, carbon fiber coated diamond is growing using a thermal chemical vapour deposition approach and C2H2 as the reaction gas. Diamond and TiC composite is grown using microwave-plasma enhanced chemical vapour deposition method. The construction of pseudocapacitors using soluble redox electrolytes will be detailed. The performance of these SCs including capacitances and capacitance retention, power and energy densities of these SCs by use of the assembled two-electrode symmetrical devices will be highlighted. For example, using the capacitor electrode of carbon fibres/diamond, the EDLC and PC devices exhibit capacitances of 30 and 48 mF cm-2 at 10 mV s-1, respectively. After 10000 charge/discharge cycles, they remain constant. Their power densities are 27.3 kW kg-1 and 25.3 kW kg-1 together with their energy densities of 22.9 Wh kg-1 and 44.1 Wh kg-1, respectively.4 The performance comparison of these SCs with those reported using other diamond capacitor electrodes will be discussed and outlined.

Resume : Fluorescent nanodiamonds (FNDs) have reported as a novel fluorescent probe with unique optical properties. Fluorescence from nitrogen-vacancy centers (NVCs) in FNDs shows neither photoblinking nor photobleaching, which enables quantitative and long-term imaging in vitro and in vivo. Besides, a quantum states of the electron spins in NVCs can be read out optically, which render FNDs as a nanoscale sensor for magnetic- and electric-field and temperature inside a single cell (Degen et al., Annu. Rev. Phys. Chem. 2014, 65:83–105). They have drawn a great deal of attention since the invention and their development potential and applications in the life sciences are proving to be manifold and vast. Nevertheless, the realization of such applications remains limited by their interfacial properties, which give them low colloidal stability of FNDs and a tendency to aggregate. In my presentation, I will show our recent achievement of the FND-based technologies including surface modification by photo-crosslinked lipid, hyperbranched polyglycerol, and polydopamine followed by gold nanoparticles. I then will show bioapplications of surface-modified FNDs such as specific cell labeling, long-term tracking of membrane proteins, and temperature sensing at nanoscale.

Resume : In biological fluids, proteins adsorb onto the surface of nanoparticles (NPs) to form a coating known as protein corona. Most of the corona proteins act as opsonin which activates the macrophage from immune system to uptake NPs, leading to the rapid removal of NPs1). This restricts the development of nanomedicine. Although conjugation with linear polyethylene glycol (PEG) is the standard approach to reduce protein attachment and to avoid non-specific uptake, it cannot fully prevent the opsonization. On the other hand, we suggested polyglycerol (PG) as a promising alternative to PEG, because PG enhanced the aqueous dispersibility and gave stealth effect to the nanoparticles2). In order to understand the roll of PG, we compare protein affinity and stealth effect of PG and PEG grafted nanodiamond (ND-PG and ND-PEG, respectively) with different density in this paper. Protein analyses by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that PG was much more resistant than PEG to adsorption of the opsonin proteins such as IgG and complement protein. In particular, there was almost no protein on the dense PG layer. In vitro stealth effect was revealed by TEM; almost no ND-PG was observed in the TEM images of U937 macrophage, while there was ND-PEG in the macrophage. This indicates that PG has much better stealth effect than PEG. In vivo stealth effects including blood circulation and biodistribution will be reported in due course. References: 1) S. Schöttler et al., Nat. Nanotechnol., 2016, 2) L. Zhao, N. Komatsu et al., Angew. Chem. Int. Ed. 2011

Resume : Diamond magnetometry has recently become a hot topic in solid state physics. The technique promises magnetic resonance measurements with unprecedented sensitivity. The goal of my team is to apply this new technology for sensing in a cell. To achieve this goal we internalize nanodiamonds inside cells. Depending on the cell type, diamonds are either ingested readily[1] or have to be modified[2] (or the cell has to be modified). The drug delivery and gene transfection fields provide a rich source of methods which can be applied for diamond particles as well. The toughest cells for uptake we have targeted successfully are yeast cells with a rigid cell wall. These can be penetrated by forming holes in the cell wall [3] or removing it entirely[4]. Once the diamond particle is ingested, we make use of the fact that NV centers in diamonds can change their optical properties based on their magnetic surrounding. The goal is to measure metabolic changes during stress responses. Finally, I will present our first successful measurements from the cell interior. [1] Hemelaar, S.R., De Boer, P., Chipaux, M., Zuidema, W., Hamoh, T., Martinez, F.P., Nagl, A., Hoogenboom, J.P., Giepmans, B.N.G. and Schirhagl, R., 2017. Nanodiamonds as multi-purpose labels for microscopy. Scientific reports, 7(1), p.720. [2] Zheng, T., Perona Martínez, F., Storm, I.M., Rombouts, W., Sprakel, J., Schirhagl, R. and De Vries, R., 2017. Recombinant protein polymers for colloidal stabilization and improvement of cellular uptake of diamond nanosensors. Analytical chemistry, 89(23), pp.12812-12820. [3] Hemelaar, S.R., van der Laan, K.J., Hinterding, S.R., Koot, M.V., Ellermann, E., Perona-Martinez, F.P., Roig, D., Hommelet, S., Novarina, D., Takahashi, H. and Chang, M., 2017. Generally Applicable Transformation Protocols for Fluorescent Nanodiamond Internalization into Cells. Scientific reports, 7(1), p.5862. [4] Morita, A., Martinez, F.P.P., Chipaux, M., Jamot, N., Hemelaar, S.R., van der Laan, K.J. and Schirhagl, R., 2019. Cell Uptake of Lipid‐Coated Diamond. Particle & Particle Systems Characterization, p.1900116.

Resume : Whatever the application considered (electronic device, catalysis or nanomedicine), electron production by nanomaterials is an essential phenomenon. As regards nanomedicine, detonation nanodiamonds were shown to improve significantly the effects of irradiation in cellulo(1). We first investigated their oxidative radical production. For that we developed a protocol to obtain absolute quantification of hydroxyl radicals in solution (2,3) and modified it to obtain solvated electrons production in solution. Based on coumarin fluorescence, this very sensitive method was adapted to avoid several pitfalls often encountered in the presence of nanoparticles. This allowed us to quantify the solvated electrons produced as a function of nanoparticle concentration, when submitted to gamma and X-ray irradiation. Behaviours of detonation nanodiamonds with different surface chemistries were compared, combined with a fine surface characterization before and after irradiation. This leads us to propose that, as for other nanomaterials, interfacial water can be significantly different from bulk water and can be mainly responsible for important radicals’ production by nanoparticles under irradiation.

Resume : Intercalation of molecules between graphene and its substrate has been widely studied as it may induce decoupling to form quasi-free-standing layers [1] and allow graphene to act as a storage medium for chemistry in confinement [2]. Using near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) we investigated the reaction of chemical vapour deposition (CVD) graphene on a Cu substrate annealed in NH3. These studies establish an N 1s peak at 405 eV which persists both when maintained at atmospheric conditions and under ultra-high vacuum (UHV) heating up to 595 K. Vapour reference peaks indicate that this peak is not correlated with the binding energy of the NH3 vapour peak and is also far higher than the three common N doped graphene peaks. Previous works on carbon nanotubes (CNT) have assigned peak values of between 404-405 eV to N2 molecules trapped within the hollow or intercalated between the graphite layers of the CNTs [3]. Comparisons of Raman and Atomic Force Microscopy (AFM) data gathered pre- and post-anneal demonstrate the effects of N2 entrapment, leading to the formation of graphene nanobubbles (GNBs). In this talk I aim to outline our understanding of this process, the mechanism of N2 formation and how it alters graphene’s intrinsic properties. References: [1] M. Oliveira et al., Carbon 52, 83 (2013) [2] P. Stutter, J. Sadowski and E. Sutter, J. Am. Chem. Soc. 132, 8175 (2010) [3] T. Susi, T. Pichler and P. Ayala, Beilstein J Nanotechnol. 6, 177 (2015)

Resume : As a two-dimensional building block for carbon allotropes of every other dimensionality, graphene has been intensively studied due to its powerful mechanical, optical, thermal and electronic properties. The present goal of graphene research is, besides the insight of the fundamental aspects, the ability to synthesize high-quality graphene on a large-scale and having control over its production phases. Graphene sheets are naturally stacked inside Highly Oriented Pyrolytic Graphite (HOPG) and its exfoliation into one-atom-thin sheets can be electrochemically achieved in electrolytic solutions. During such routines, the solvated anions penetrate in the basal graphite planes and, overcoming the non-covalent interaction between graphene sheets, promote the graphite delamination. The final preservation of graphene properties is closely linked to the changes that occur in the graphitic matrix. Currently, complete knowledge of the chemical and physical processes at the base of such changes has not been experimentally supported yet. Here we describe from a chemical point of view, by using a new approach combining ToF-SIMS and in-situ SPM, the effects of the ion intercalation on the HOPG surface and bulk. In particular, we will show, with molecular accuracy, the structural connection between the surface defects and the spatial arrangement of the molecular groups from the solvent. Furthermore, a new picture of the ion intercalation process, based on the results of low-energy ion beam depth profiling experiments, will be proposed.

Resume : Hydrogenated detonation nanodiamonds (H-DND) showed promising assets for bio-applications. For example, cationic H-DND suspended in water were used as an efficient vector for small interfering RNA [1]. Their radiosensitisation behaviour was reported in vitro for radioresistant cancer cells [2] and an overproduction of hydroxyl radicals occurred in water under X-ray irradiation [3]. To achieve a fine control of these properties, a better knowledge of the H-DND surface chemistry is required. In the present study, we used an original approach based on the use of hydrogen isotopes [4]. DND were thermally annealed in a closed system. To synthesize isotopically labelled DND, their thermal annealing in a closed system under D2 ot T2 gas was carefully optimized. Deuterium and tritium-treated DND were characterised by complementary techniques: FTIR, Raman spectroscopy, DLS, 3H/2H/1H and 13C MAS NMR. The origin of C-H terminations at the DND surface after hydrogenation process was discriminated from deuterated DND while tritium treated DND allowed a quantification of hydrogen. Our experiments showed it is possible to tune the hydrogen amount on H-DND. Moreover, the nature of the C-1,2,3H bonds was demonstrated by 1,2,3H NMR. [1] Bertrand et al., Biomaterials 45 (2015) [2] Grall et al., Biomaterials 61 (2015) [3] Kurzyp et al., Chem. Comm. 53 (2017) [4] Nehlig et al., Nanoscale 11 (2019)

Resume : Upon contact with physiological medium, nanoparticles (NPs) will be covered by a protein corona layer. This protein corona alters not only the surface property of NPs, but also their interactions with biological system. Understanding the corona formation process is crucial for predicting the biological fate of NPs. It is reported that hydrophobic interactions and electrostatic attractions were the driving forces for protein attachment 1), but there is lack of stoichiometric description of these interactions. Here, we quantitatively evaluate NP hydrophilicity to protein affinity. Nanodiamond (ND) coated by polyethylene glycol (PEG) and polyglycerol (PG) in different density were used as hydrophilic platforms. Bovine serum albumin (BSA), gamma globulin (Ƴ-GLO), and fibrinogen (FIB) were selected as model proteins. Corona proteins were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and quantified via bicinchoninic acid assay (BCA). The results indicated that BSA and Ƴ-GLO formed monolayers on the bare ND surface, while FIB formed multilayer corona. The number of protein molecules on a single ND decreased from 193 to 11 as PG density increased from 10 to 20 wt%. In particular, there was no protein on ND-PG surface when PG density reached 30 wt%. Taking advantage of the transparent background of PG, we further investigate the net charge effect; some of the hydroxy groups on PG were substituted by amino and carboxyl groups which gave plus and minus surface potentials, respectively 2). Their affinity toward various proteins with different isoelectric point will be quantified. References: 1) R. Haag et al., Angew. Chem. Int. Ed., 2014; 2) L. Zhao, N. Komatsu and et al., Adv. Funct. Mater., 2014