A novel process to produce microcellular thermoplastic parts is described. This is achieved by integrating the deformation process in the foaming cycle in such a way that the cell nucleation and growth processes are effectively uncoupled from deformation. The nitrogen-polystyrene system is studied and the relationships between the essential process parameters are established. It is experimentally shown that the pressures associated with deformation do not reduce the number of bubbles nucleated. The process synthesized is demonstrated by making a microcellular polystyrene container.

Recently developed triboelectric nanogenerators (TENGs) act as a promising power source for self-powered electronic devices. However, the majority of TENGs are fabricated using metallic electrodes and cannot achieve high stretchability and transparency, simultaneously. Here, slime-based ionic conductors are used as transparent current-collecting layers of TENG, thus significantly enhancing their energy generation, stretchability, transparency, and instilling self-healing characteristics. This is the first demonstration of using an ionic conductor as the current collector in a mechanical energy harvester. The resulting ionic-skin TENG (IS-TENG) has a transparency of 92% transmittance, and its energy-harvesting performance is 12 times higher than that of the silver-based electronic current collectors. In addition, they are capable of enduring a uniaxial strain up to 700%, giving the highest performance compared to all other transparent and stretchable mechanical-energy harvesters. Additionally, this is the first demonstration of an autonomously self-healing TENG that can recover its performance even after 300 times of complete bifurcation. The IS-TENG represents the first prototype of a highly deformable and transparent power source that is able to autonomously self-heal quickly and repeatedly at room temperature, and thus can be used as a power supply for digital watches, touch sensors, artificial intelligence, and biointegrated electronics.

Ferroelectric materials have attracted interest in recent years due to their application in energy harvesting owing to its piezoelectric nature. Ferroelectric polymers are flexible and can sustain larger strains compared to inorganic counterparts, making them attractive for harvesting energy from mechanical vibrations. Herein, we report, for the first time, the enhanced piezoelectric energy harvesting performance of the bilayer films of poled poly(vinylidene fluoride-trifluoroethylene) [PVDF-TrFE] and graphene oxide (GO). The bilayer film exhibits superior energy harvesting performance with a voltage output of 4 V and power output of 4.41 μWcm(-2) compared to poled PVDF-TrFE films alone (voltage output of 1.9 V and power output of 1.77 μWcm(-2)). The enhanced voltage and power output in the presence of GO film is due to the combined effect of electrostatic contribution from graphene oxide, residual tensile stress, enhanced Young's modulus of the bilayer films, and the presence of space charge at the interface of the PVDF-TrFE and GO films, arising from the uncompensated polarization of PVDF-TrFE. Higher Young's modulus and dielectric constant of GO led to the efficient transfer of mechanical and electrical energy.

Porous WO3 films with ultra-high transmittance modulation were successfully fabricated on different substrates by a novel electrochemical deposited method.

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A process to produce a family of novel materials from polycarbonate, having a microcellular structure, is described. The process utilizes the high solubility of carbon dioxide in polycarbonate to nucleate a very large number of bubbles, on the order of 1 to 10 × 109 bubbles/cm3, at temperatures well below the glass transition temperature of the original, unsaturated polycarbonate. Microcellular polycarbonate foams with homogeneous microstructure and a wide range of densities have been produced. In this paper experimental results on solubility, bubble nucleation, and bubble growth in the polycarbonate-carbon dioxide system are presented, and the critical ranges of the key process parameters are established. It is shown that the bubble nucleation phenomenon in polycarbonate near the glass transition temperature is not described by classical nucleation theory.

Metal‐organic frameworks (MOFs) have received increasing attention as promising electrode materials in supercapacitors. Yet poor conductivity in most MOFs largely inhibits their capacitance and/or rate performance. An effective strategy is developed to reduce the bulk electrical resistance of MOFs by exchanging organic ligands with PO43− groups that adopt the external morphology of the MOFs.

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