Sprecher
Beschreibung
Polymeric aerogels have attracted considerable attention as sustainable porous materials due to their high porosity, ultralow density, large specific surface area, and tunable hierarchical structures. This talk highlights the development of advanced polymeric aerogels for two important applications: energy harvesting and solar-driven atmospheric water harvesting (SAWH) [1]. The first part focuses on a directional freeze-casting approach for fabricating isotropic and anisotropic nylon-11 aerogels. By controlling the freezing temperature, highly aligned pore channels and oriented polar g-phase nylon-11 crystals are obtained, leading to enhanced mechanical properties and piezoelectric performance. These anisotropic aerogels generate output voltages of ~30 V and power densities of 0.1 W m-3. Vacuum-assisted infiltration of PVDF further induces oriented b-phase PVDF, producing self-poled hybrid aerogels with output voltages of ~45 Vpp and peak power densities of 2.2 W m-3. In addition, anisotropic nylon-11 aerogels exhibit strong tribo-positive behavior, delivering up to 277 Vpp in triboelectric nanogenerators, which increases to 650 Vpp upon incorporation of silk nanofibrils. The second part describes biodegradable poly(3-hydroxybutyrate) (PHB)-based composite aerogels for SAWH. These aerogels incorporate MgCl2·6H2O as a hygroscopic component and carbon nanotubes as photothermal converters within a porous PHB network. The resulting materials exhibit high water uptake across a broad humidity range, reaching 1.64 g g-1 at 90% RH and 0.88 g g-1 at 40% RH, together with rapid solar-driven water release at a rate of 1.8 g g-1 h-1 under one-sun irradiation. The aerogels also show excellent cycling stability, fast adsorption-desorption kinetics, and environmental sustainability due to the biodegradability of PHB. Overall, these studies demonstrate how controlling polymer crystallization, pore architecture, and multifunctional hybridization can create sustainable polymeric materials for efficient energy harvesting and atmospheric water generation.