Despite increasing application of silver nanoparticles (NPs) in industry and consumer products, there is still little known about their potential toxicity, particularly to organisms in aquatic environments. To investigate the fate and effects of silver NPs in fish, rainbow trout (Oncorhynchus mykiss) were exposed via the water to commercial silver particles of three nominal sizes: 10 nm (N(10)), 35 nm (N(35)), and 600-1600 nm (N(Bulk)), and to silver nitrate for 10 days. Uptake into the gills, liver, and kidneys was quantified by inductively coupled plasma-optical emission spectrometry, and levels of lipid peroxidation in gills, liver, and blood were determined by measurements of thiobarbituric acid reactive substances. Expression of a suite of genes, namely cyp1a2, cyp3a45, hsp70a, gpx, and g6pd, known to be involved in a range of toxicological response to xenobiotics was analyzed in the gills and liver using real-time PCR. Uptake of silver particles from the water into the tissues of exposed fish was low but nevertheless occurred for current estimated environmental exposures. Of the silver particles tested, N(10) were found to be the most highly concentrated within gill tissues and N(10) and N(Bulk) were the most highly concentrated in liver. There were no effects on lipid peroxidation in any of the tissues analyzed for any of the silver particles tested, and this is likely due to the low uptake rates. However, exposure to N(10) particles was found to induce expression of cyp1a2 in the gills, suggesting a possible increase in oxidative metabolism in this tissue.

Three different electron beam irradiated fluoropolymers (ETFE, FEP, and PVDF) as well as their grafting reactions with styrene in different diluents were investigated by means of electron spin resonance (ESR). Depending on the atmosphere during irradiation, ESR spectra of peroxy and alkyl radicals were observed. Radical decay as a function of time and temperature was investigated in the presence and absence of solvent. Grafting levels and number of monomer units per chain were calculated for both types of radicals. Irradiation atmosphere, grafting temperature, and added solvent affect the morphology of the fluoropolymers, in particular the crystalline versus amorphous fractions and their swelling. They thus influence the rate at which the initial radicals at the polymer backbone are reached during the grafting process.

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Membranes based on sulfonated arylene polymers and their cross‐linked blends were prepared. Embedding the ionomers into textile or porous PTFE matrix and/or doping with ZrP nanoparticles reduced the swelling, and improved the thermal stability. PTFE reinforcement led to an excellent single cell performance, which is promising for PEMFC applications. Some of the membranes performed better than Nafion®. The net methanol crossover correlates with the membrane thickness and composition, but surprisingly, suppression of the methanol crossover alone, does not enhance U/I performance. ESR experiments of oxidative degradation of the monomer by OH• at pH > 10 leads to phenoxyl and semi‐quinone radicals. The study focuses on the case where O2•– or 1O2 are the damaging species, i.e. above pH 11.7, and the dominant reaction is that involving the aromatic ring. Under conditions of fuel starvation, the acid protons get depleted, which may lead to high local pH values, even in an overall acidic environment. It is therefore important to be aware of the entirely different form of degradation chemistry at high pH. In the presence of both HO• radicals and oxygen, complete degradation of the aromatic rings can be observed, within hours. In view of this, perfluorinated membranes are more inert. Cross‐linked arylene polymer blend membranes and PTFE‐reinforced arylene ionomer membranes can be regarded as promising for further development, due to their high stability and excellent PEMFC performance.