Summary: The structure of the free volume and its temperature dependence between 25 and 190 °C of copolymers of styrene with acrylonitrile, SAN (0 to 50 mol‐% AN), is studied by pressure volume temperature (PVT) experiments and positron annihilation lifetime spectroscopy (PALS). In this second part of the work, PALS data are reported from which the temperature dependence of the mean size and size distribution of local free volumes (subnanometer size holes) is analysed. The mean hole volume, vh, varies in PS between 105 Å3 (27 °C) and 220 Å3 (190 °C), and shows a systematic decrease with increasing AN content, at Tg from 121 Å3 for PS to 102 (±2) Å3 for SAN50. The specific number of holes, $N_{\rm h} '$, estimated from a comparison of PVT and PALS results, is independent on the temperature and the composition of SAN, $N_{\rm h} '$ = (0.56 ± 0.02) × 1021 g−1 which corresponds to Nh(Tg) = $N_{\rm h} '$/V(Tg) = 0.59 nm−3 and 1/Nh(Tg) = 1.7 nm3 for the volume which contains one hole. The analysed size distributions of the holes above Tg follow the compressibility of the free volume as it is predicted by the theory of thermal volume fluctuation. Moreover, we showed that the bulk elasticity modulus follows mastercurves as a function of vh above and below Tg.Free volume hole radius distribution n(rh) in PS for three different temperatures.magnified imageFree volume hole radius distribution n(rh) in PS for three different temperatures.

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The time taken for positrons to reach thermal equilibrium in a number of simple molecular gases has been estimated using the gas mixture technique devised by Paul and Leung (Paul D A L and Leung C Y Can. J. Phys. 46 2779-88). Times below 100 ps Amagat have been found for a number of species, suggesting their use as efficient coolers for rapid-cycle positron traps and accumulators.

Uniform and vertically aligned nanotube arrays of titanium oxynitride functionalized with iridium nanoparticles (Ir/TiON-NTs) were fabricated for the solar driven-water splitting.

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