(283c) Functionalized Porous Materials As Liquid Springs for Energy Conversion

For a few decades, shape-memory materials, also known as smart materials, have drawn increasing attention. In general, any materials or structures that change their dimensions or configurations as temperature varies can be potentially used to develop thermally controllable intelligent systems. The functionalized porous materials lead to a high degree of hydrophobicity. When the external pressure is low, water does not enter the nanopores, due to the well known capillary effect. When the pressure is relatively high, it becomes energetically favorable for the liquid molecules to enter the nanopores, and pronounced pressure-induced infiltration occurs. Since the infiltration and defiltration of water can be controlled by adjusting external pressure and the hysteresis of sorption isotherm is negligible, the system behaves as a ‘liquid spring’ where mechanical energy is converted to the interfacial energy. With the addition of sodium chloride, the temperature sensitivity of the system increases with the electrolyte concentration, beneficial to improving the output energy density. Due to the large surface area, its energy density and the deformability are much higher than that of conventional shape-memory solids.