2022, Besford, Quinn A., Cavalieri, Francesca

[no abstract available]

2020, Wojnarowska, Zaneta, Musiał, Małgorzata, Cheng, Shinian, Gapinski, Jacek, Patkowski, Adam, Pionteck, Jürgen, Paluch, Marian

Herein, we investigate the charge transport and structural dynamics in the supercooled and glassy state of protic ionic material with an efficient interionic Grotthuss mechanism. We found that superprotonic properties of studied acebutolol hydrochloride (ACB-HCl) depend on thermodynamic conditions with the most favorable regions being close to the glass-transition temperature (Tg) and glass-transition pressure (Pg). To quantify the contribution of fast proton hopping to overall charge transport over a broad T–P space, we employed the density scaling concept, one of the most important experimental findings in the field of condensed matter physics. We found that isothermal and isobaric dc-conductivity (σdc) and dynamic light scattering (τα) data of ACB-HCl plotted as a function of (TVγ)−1 satisfy the thermodynamic scaling criterion with the ratio γσ/γα appearing as a new measure of fast charge transport in protic ionic glass-formers in the T–P plane. Such a universal factor becomes an alternative to the well-known Walden rule being limited to ambient pressure conditions.

2020, Apelt, Sabine, Höhne, Susanne, Uhlmann, Petra, Bergmann, Ute

Active deicing of technical surfaces, such as for wind turbines and heat exchangers, currently requires the usage of heat or chemicals. Passive coating strategies that postpone the freezing of covering water would be beneficial in order to save costs and energy. One hypothesis is that pyroelectric active materials can achieve this because of the surface charges generated on these materials when they are subject to a temperature change. High-quality poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) thin films with a high crystallinity, prefererd edge-on orientation, low surface roughness, and comprised of the β-analogous ferroelectric phase were deposited by spin-coating. Freezing experiments with a cooling rate of 1 K min−1 were made on P(VDF-TrFE) coatings in order to separate the effect of different parameters such as the poling direction, film thickness, used solvent, deposition process, underlying substrate, and annealing temperature on the achievable supercooling. The topography and the underlying substrate significantly changed the distribution of freezing temperatures of water droplets in contact with these thin films. In contrast, no significant effect of the thickness, morphology, or pyroelectric effect of the as-prepared domain-state on the freezing temperatures was found.