A methodology on how to create a real-life relevant risk profile for a given nanomaterial

With large amounts of nanotoxicology studies delivering contradicting results and a complex, moving regulatory framework, potential risks surrounding nanotechnology appear complex and confusing. Many researchers and workers in different sectors are dealing with nanomaterials on a day-to-day basis, and have a requirement to define their assessment/management needs. This paper describes an industry-tailored strategy for risk assessment of nanomaterials and nano-enabled products, which builds on recent research outcomes. The approach focuses on the creation of a risk profile for a given nanomaterial (e.g., determine which materials and/or process operation pose greater risk, where these risks occur in the lifecycle, and the impact of these risks on society), using state-of-the-art safety assessment approaches/tools (ECETOC TRA, Stoffenmanager Nano and ISO/TS 12901-2:2014). The developed nanosafety strategy takes into account cross-sectoral industrial needs and includes (i) Information Gathering: Identification of nanomaterials and hazards by a demand-driven questionnaire and on-site company visits in the context of human and ecosystem exposures, considering all companies/parties/downstream users involved along the value chain; (ii) Hazard Assessment: Collection of all relevant and available information on the intrinsic properties of the substance (e.g., peerreviewed (eco)toxicological data, material safety data sheets), as well as identification of actual recommendations and benchmark limits for the different nano-objects in the scope of this projects; (iii) Exposure Assessment: Definition of industry-specific and application-specific exposure scenarios taking into account operational conditions and risk management measures; (iv) Risk Characterisation: Classification of the risk potential by making use of exposure estimation models (i.e., comparing estimated exposure levels with threshold levels); (v) Refined Risk Characterisation and Exposure Monitoring: Selection of individual exposure scenarios for exposure monitoring following the OECD Harmonized Tiered Approach to refine risk assessment; (vi) Risk Mitigation Strategies: Development of risk mitigation actions focusing on risk prevention.This work was supported by ongoing projects that received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no 646155 (INSPIRED), grant agreement no 646296 (Hi-Response) and grant agreement no 691095 (NANOGENTOOLS)

Anti-icing solutions combining printed electronics and nanotexturing of Al alloys

Aluminum superhydrophobic (SHP) surfaces have been prepared by the combination of chemical microtexturing and surface functionalization with long-chained polyfluoroalkyl moieties. On the opposite side to the modified surface self-limiting heating element has been printed using carbon based possitive temperature coefficient (PTC) inks. Different heater configurations were tested to optimize heater design. Results showed that the combination of both strategies was able to maintain the aluminum surface ice free under tested conditions. The developed hybrid system showed good performance under anti-icing conditions with potential to be applied in aircraft systems

Superhydrophobic and oleophobic microtextured aluminum surface with long durability under corrosive environment

Abstract Superhydrophobic (SHP) and oleophobic aluminum surfaces have been prepared through the combination of a scalable chemical microtexturing process and surface functionalization with long-chained polyfluoroalkyl moieties. The effect of an anodic layer on the microtextured surface has been assessed considering surface morphology, superhydrophobicity, surface mechanical properties and corrosion protection enhancement. The surface functionalization with polyfluoroalkyl moieties has been tackled in two different ways: (i) grafting of the polyfluoroalkyl moieties and (ii) deposition of a thin hybrid coating with low content of polyfluoroalkyl-containing compound. Aluminum surfaces showing high durability in salt spray environments, which maintain SHP and oleophobic properties at least up to 2016 h have been attained. Applications for this kind of surfaces range from easy-to-clean surfaces to anti-icing or anti-condensation functionalities that could be of interest for several sectors

Control of the properties of carbon nanotubes synthesized by CVD for application in electrochemical biosensors

Interest in carbon nanotubes (CNT) has grown at a very rapid rate in the last decade. Their interesting physical and chemical properties open attractive possibilities in many application areas. These properties depend on the process conditions during synthesis and on subsequent purification steps. Recent studies have demonstrated that CNT can promote the electron transfer of biomolecules. These exceptional properties make them attractive for use in electrochemical biosensors. Multi walled nanotubes have been synthesized by the Chemical Vapor Deposition (CVD) method using methane as a carbon source and Ni-Al 2O3-SiO2 as the catalyst. The influence of the variation of certain reaction parameters such as feed gas composition, catalyst mass, temperature and reaction time in the yield of the CVD process has been established. In addition, the structural and chemical characteristics of the CNTs have been studied and a purification process to eliminate the catalyst and amorphous carbon has been developed that involves a gaseous oxidative process and acid treatment. The efficiency of the purification step has been determined by analytical techniques. Atomic force microscopy, Raman scattering, thermogravimetric analysis, inductively coupled plasma atomic spectroscopy are the characterization techniques employed in this work.Peer reviewe

Single-walled carbon nanotubes and multiwalled carbon nanotubes functionalized with poly(L-lactic acid): A comparative study

Spectroscopic (Raman) and gravimetric (acid titration, TGA) techniques were compared to determine the functionalization degree of multiwalled carbon nanotubes (MWNTs) and single-walled carbon nanotubes (SWNTs) with poly(L-lactic acid) (PLLA), following a two-step oxidation/esterification process. After oxidation with HNO3, carbon nanotubes (CNTs) were activated with thionyl chloride to the corresponding acid chlorides and then grafted with PLLA. FTIR spectroscopy confirmed the formation of very similarly grafted CNT-PLLA materials for both SWNT and MWNT. But, according to chemical titration and TGA results, oxidized and esterified SWNT showed a significantly higher degree of functionalization than their MWNT counterparts. Contrary to these observations, the increase of the Raman ID/IG ratio was higher for MWNT-derived materials than for the SWNT counterparts. Therefore, it was concluded that this spectroscopic technique is unsuitable for the quantitative determination of the degree of functionalization when MWNT and SWNT are compared.Peer reviewe

Electro-assisted solvent extraction of Cu2+, Ni2+ and Cd2+

A novel separation method, i.e. electro-assisted solvent extraction, based on the principles of two-phase electrochemistry, has been demonstrated for the successful separation of Ni2+, Cu2+ and Cd2+ ions. 2-Heptanone has been used as the organic solvent for the transfer of Ni2+, Cu2+ and Cd2+ facilitated by 2,2′;6′,2″-terpyridine. It is shown that extraction efficiency depends on the concentration ratio of ligand to metal ion and importantly, on the applied interfacial potential difference. It was found that Ni2+ (not Cd2+ or Cu2+) extraction is suppressed in the presence of Mg2+ ion due to competitive complexation.Financial support from the EC commission (Brite-Euram, Contract MA2R-CT91-0012 on Liquid Membranes for Electro-assisted Refining and Recycling of Metals) is gratefully acknowledged.Peer reviewe

Reductive functionalization of single-walled carbon nanotubes with lithium metal catalyzed by electron carrier additives

Lithium metal can be used to reduce single-walled carbon nanotubes (SWNT) to carbide-like species under the catalytic effect of di-tert-butyl-biphenyl (DTBP). The resulting nanotube polycarbanions show a significantly increased dispersability in THF and react "in situ" with trimethylchlorosilane, methyl methacrylate, and methyl N-acetamidoacrylate to afford covalently functionalized silyl nanotubes and polymer-wrapped SWNT. The density and average length of the polymer chains attached to the nanotube wall can be widely modified by varying the amount of monomer, lithium, and catalyst.Peer reviewe

Embedded Printed Split Ring Resonators in Polymer Composites for Temperature Sensing

Publisher Copyright: © 2024 IEEE.In this paper novel printed RF temperature sensors embedded in a composite based on single and double SRRs are proposed. The resonators have been printed on fiber-glass fabrics and embedded in an epoxy composite by means of a VIC. Due to the temperature dependence of the composite permittivity, the resonance frequency changes with temperature and -0.825 MHz/°C and -0.979 MHz/°C sensitivities have been obtained for the single and double resonators respectively. The paper presents the fabrication process together with simulation and measured results. These results lead to a proof of concept of these sensors that would be suitable for use as part of a whole wireless passive sensor system in the future.Peer reviewe

Silver and copper screen-printed temperature sensors on flexible substrates: The impact of ink sintering conditions and composition

Publisher Copyright: © 2024 Wiley-VCH GmbH.Fully screen-printed silver and copper temperature sensors were studied up to 100°C. The influence of the processing conditions and the composition of three silver and one copper commercial inks is analyzed in this study. The curing temperature is extremely relevant to stabilize the initial resistance of silver sensors, especially for those printed with the lowest solid content ink. All printed sensors showed good linear behavior in the range of 25–100°C (R2 > 0.999) except for those fabricated with the lowest solid content silver ink, which also displayed the highest hysteresis and drift. The temperature coefficient of resistance (TCR) obtained for the copper sensors was 3.367 × 10−3 K−1 and for the three silver sensors, it ranged between 2.723 × 10−3 to 2.963 × 10−3 K−1. This TCR is higher than values reported for inkjet-printed resistive temperature detectors. Overall, this work demonstrates that low-cost, linear, screen-printed temperature sensors can be successfully fabricated on flexible substrates.Peer reviewe