Graphene-based composite with high stable dispersion in ethanol.

In the last few years a lot of applicative research studies are focused on graphene, a 2D carbo-material with very particular physical features like electro-conductivity, thermo-conductivity, mechanical stability, and its particular aspect ratio with a high surface and a negligible thickness (1–3). For that features the spectra of possibilities to make a new application with this material, are big and grow time after time. In addition, with climate change, the focus of research to make new technologies greener and with less impact, on the environment, than now has moved to increase the study of that material and most researchers have focused their studies on the possibility to disperse that material in a green solvent with low boiling point. One problem with pristine Graphene is that it could be dispersed with high concentration only in polar aprotic solvent as n-methyl-2-pyrrolidone or Dimethyl formamide (4), a solvent with a high boiling point and with high toxicity for the humans and the environment. Usually for that reason is preferred to use the oxidized form of graphene GO, most easy to disperse, and reduce in rGO. The reduced form has the problem of having more defects on the surface than pristine graphene losing a part of the natural performance of the graphene. Another method studied is the use of a surfactant (5)or making nano-composite material with the use of polar polymer such as the PVP (6–8) has permitted to disperse of the material with a good concentration in water. This research has moved used to investigate how to make new composite graphene-based, easy to disperse in an organic polar solvent such as ethanol. We made an uncontrolled growth of polymer (ethyl maleate derivate) on the surface of the material, for making that we use the support of the microwave reactor that, with the particular characteristic of the graphene to be a radical initiator, permits the formation of different particles of polymer maleate based on the surface of the graphene. This material has good stability in ethanol and maintains that feature after a long time. That dispersion opens the possibility to make ink graphene-based or coating on other surfaces and other different applications with the fast removal of the solvent. At the same time the uncontrolled growing permit the removal of the composite with the heating of the material in an inert atmosphere to obtain pristine graphene with a low number of defects. Bibliography 1. Clancy AJ, Bayazit MK, Hodge SA, Skipper NT, Howard CA, Shaffer MSP. Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes. Chem Rev. 2018;118(16):7363-7408. doi:10.1021/acs.chemrev.8b00128 2. Randviir EP, Brownson DAC, Banks CE. A decade of graphene research: Production, applications, and outlook. Mater Today. 2014;17(9):426-432. doi:10.1016/j.mattod.2014.06.001 3. Wei W, Qu X. Extraordinary physical properties of functionalized graphene. Small. 2012;8(14):2138-2151. doi:10.1002/smll.201200104 4. Vacacela Gomez C, Guevara M, Tene T, et al. The liquid exfoliation of graphene in polar solvents. Appl Surf Sci. 2021;546(December 2020):149046. doi:10.1016/j.apsusc.2021.149046 5. Wang S, Yi M, Shen Z, Zhang X, Ma S. Adding ethanol can effectively enhance the graphene concentration in water-surfactant solutions. RSC Adv. 2014;4(48):25374-25378. doi:10.1039/c4ra03345k 6. Laaksonen P, Kainlauri M, Laaksonen T, et al. Interfacial engineering by proteins: Exfoliation and functionalization of graphene by hydrophobins. Angew Chemie - Int Ed. 2010;49(29):4946-4949. doi:10.1002/anie.201001806 7. Perumal S, Lee HM, Cheong IW. High-concentration graphene dispersion stabilized by block copolymers in ethanol. J Colloid Interface Sci. 2017;497:359-367. doi:10.1016/j.jcis.2017.03.027 8. Wajid AS, Das S, Irin F, et al. Polymer-stabilized graphene dispersions at high concentrations in organic solvents for composite production. Carbon N Y. 2012;50(2):526-534. doi:10.1016/j.carbon.2011.09.00

Biochar/Zinc Oxide Composites as Effective Catalysts for Electrochemical CO2 Reduction

Novel electrocatalysts based on zinc oxide (ZnO) and biochars are prepared through a simple and scalable route and are proposed for the electrocatalytic reduction of CO₂ (CO₂RR). Materials with different weight ratios of ZnO to biochars, namely, pyrolyzed chitosan (CTO) and pyrolyzed brewed waste coffee (CBC), are synthesized and thoroughly characterized. The physicochemical properties of the materials are correlated with the CO₂RR to CO performance in a comprehensive study. Both the type and weight percentage of biochar significantly influence the catalytic performance of the composite. CTO, which has pyridinic- and pyridone-N species in its structure, outperforms CBC as a carbon matrix for ZnO particles, as evidenced by a higher CO selectivity and an enhanced current density at the ZnO_CTO electrode under the same conditions. The study on various ZnO to CTO weight ratios shows that the composite with 40.6 wt % of biochar shows the best performance, with the CO selectivity peaked at 85.8% at −1.1 V versus the reversible hydrogen electrode (RHE) and a CO partial current density of 75.6 mA cm–² at −1.3 V versus RHE. It also demonstrates good stability during the long-term CO₂ electrolysis, showing high retention in both CO selectivity and electrode activity

Current and Future Nanotech Applications in the Oil Industry

Problem statement: Nanotech applications in the oil industry are not completely new: nanoparticles have been successfully used in drilling muds for the past 50 years. Only recently all the other key areas of the oil industry, such as exploration, primary and assisted production, monitoring, refining and distribution, are approaching nanotechnologies as the potential Philosopher's stone for facing critical issues related to remote locations (such as ultra-deep water and artic environments), harsh conditions (high-temperature and high-pressure formations), nonconventional reservoirs (heavy oils, tight gas, tar sands). The general aim is to bridge the gap between the oil industry and nanotechnology community using various initiatives such as consortia between oil and service companies and nanotechnology excellence centres, networking communities, workshops and conferences and even dedicated research units inside some oil companies. Quite surprisingly, even if a lot of discussion is taking place, no substantial research on these topics is currently being undertaken around the world by the petroleum industry. A very different attitude is demonstrated by other industries and the advances they achieved are outstanding. Approach: This study provides an overview of the most interesting nanotechnology applications and critically highlights the potential benefits that could come from transposing the same-or adapted-solutions to the oil industry. Results/Conclusion: As extensively illustrated, some technologies which are already available off-the-shelf can offer real improvements in dealing with some specific issues of the oil industry. Other technologies can require further elaboration before direct use, but their potential is enormous

SELF-HEALING HYDROGELS 3D-PRINTED VIA VAT PHOTOPOLYMERIZATION

virtual European Symposium of Photopolymer Science 202

Smart Devices and Systems for Wearable Applications

Wearable technologies need a smooth and unobtrusive integration of electronics and smart materials into textiles. The integration of sensors, actuators and computing technologies able to sense, react and adapt to external stimuli, is the expression of a new generation of wearable devices. The vision of wearable computing describes a system made by embedded, low power and wireless electronics coupled with smart and reliable sensors - as an integrated part of textile structure or directly in contact with the human body. Therefore, such system must maintain its sensing capabilities under the demand of normal clothing or textile substrate, which can impose severe mechanical deformation to the underlying garment/substrate. The objective of this thesis is to introduce a novel technological contribution for the next generation of wearable devices adopting a multidisciplinary approach in which knowledge of circuit design with Ultra-Wide Band and Bluetooth Low Energy technology, realization of smart piezoresistive / piezocapacitive and electro-active material, electro-mechanical characterization, design of read-out circuits and system integration find a fundamental and necessary synergy. The context and the results presented in this thesis follow an “applications driven” method in terms of wearable technology. A proof of concept has been designed and developed for each addressed issue. The solutions proposed are aimed to demonstrate the integration of a touch/pressure sensor into a fabric for space debris detection (CApture DEorbiting Target project), the effectiveness of the Ultra-Wide Band technology as an ultra-low power data transmission option compared with well known Bluetooth (IR-UWB data transmission project) and to solve issues concerning human proximity estimation (IR-UWB Face-to-Face Interaction and Proximity Sensor), wearable actuator for medical applications (EAPtics project) and aerospace physiology countermeasure (Gravity Loading Countermeasure Skinsuit project)

Electrospun PEO/PEDOT:PSS Nanofibers for Wearable Physiological Flex Sensors

Flexible sensors are fundamental devices for human body monitoring. The mechanical strain and physiological parameters coupled sensing have attracted increasing interest in this field. However, integration of different sensors in one platform usually involves complex fabrication process-flows. Simplification, even if essential, remains a challenge. Here, we investigate a piezoresistive and electrochemical active electrospun nanofibers (NFs) mat as the sensitive element of the wearable physiological flex sensing platform. The use of one material sensitive to the two kinds of stimuli reduces the process-flow to two steps. We demonstrate that the final NFs pH-Flex Sensor can be used to monitor the deformation of a human body joint as well as the pH of the skin. A unique approach has been selected for pH sensing, based on Electrochemical Impedance Spectroscopy (EIS). A linear dependence of the both the double layer capacitance and charge transfer re-sistance with the pH value was obtained by EIS, as well as a linear trend of the electrical resistance with the bending deformation. Gauge factors values calculated after the bending test were 45.84 in traction and 208.55 in compression mode, reflecting the extraordinary piezoresistive behavior of our nanostructured NFs

Determination of reliable resistance values for electrical double-layer capacitors

The power capabilities of supercapacitors are strongly influenced by their passive elements. Within this study, we investigate methods to address resistive components out of galvanostatic measurements and we compared literature methods with the aim to provide a guide to correctly exploit the resistance of supercapacitors. The impact of the sampling conditions of galvanostatic measurements is analyzed and related to electrochemical impedance spectroscopy. Further, a novel method based on the instantaneous power analysis is provided to get real-time information concerning the actual cell resistance during the measurement without altering the gal- vanostatic experiment. Measurements show that literature methods can provide values close to the series resistance, while the newly proposed power method results in a good estimate of the actual dissipative value

Development of New Hybrid Acrylic/Epoxy DLP-3D Printable Materials

Light induced three dimensional (3D) printing techniques generally use printable formulations that are based on acrylic monomers because of their fast reactivity, which is balanced with their good final properties. However, the possibility to enlarge the palette of 3D printable materials is a challenging target. In this work, hybrid printable formulations that are based on acrylic and epoxy resins are presented and their printability on DLP (Digital Light Processing) machines is demonstrated. Hexanediol diacrylate (HDDA) and an epoxy resin—3,4-Epoxycylohexylmethyl-3',4' epoxycyxlohexane carboxylate (CE)—in different ratios are used and the influence of a bridging agent, Glycidyl methacrylate (GMA), is also investigated. The reactivity of the different active species during irradiation is evaluated and the mechanical properties, including the impact toughness, the thermo-mechanical properties, and the volumetric shrinkage, are studied on printed samples