Stimuli-Responsive Electrospun Piezoelectric Mats of Ethylene--vinyl Acetate-Millable Polyurethane-Nanohydroxyapatite Composites.

Piezoelectric materials have gained interest among materials scientists as body motion sensors and energy harvesters on account of their fast responsiveness and substantial output signals. In this work, piezoelectric polymer mats have been fabricated from ethylene--vinyl acetate-millable polyurethane/nanohydroxyapatite (EVA-MPU/nHA) composite systems by employing the electrospinning technique. The ferro-piezoelectric features of the samples were confirmed from the butterfly loops of electrostatic force microscopy (EFM) amplitude signals as well as through the hysteresis curves of the EFM phase recorded with the assistance of dynamic-contact EFM.

Electrospun Poly(vinylidene fluoride-trifluoroethylene)-Based Polymer Nanocomposite Fibers for Piezoelectric Nanogenerators.

The present work deals with the preparation, characterization, and application of self-poled nanofibers using piezoelectric polymer poly(vinylidene fluoride-trifluoroethylene), zinc oxide, and exfoliated graphene oxide by electrospinning process. The characterization of nanofiber is carried by different techniques such as field emission scanning electron microscopy, Fourier transform Infrared spectroscopy, X-ray diffraction techniques, and dynamic contact mode electrostatic force microscopy. The nanofiber based piezoelectric nanoenergy generator devices are fabricated for analyzing the energy generating efficiency.

Fast Transport of Water Droplets over a Thermo-Switchable Surface Using Rewritable Wettability Gradient.

In spite of the reported temperature dependent tunability in wettability of poly(N-isopropylacrylamide) (PNIPAAm) surfaces for below and above lower critical solution temperature (32 °C), the transport of water droplets is inhibited by the large contact angle hysteresis. Herein, for the first time, we report on-demand, fast, and reconfigurable droplet manipulation over a PNIPAAm grafted structured polymer surface using temperature-induced wettability gradient. Our study reveals that the PNIPAAm grafted on intrinsically superhydrophobic surfaces exhibit hydrophilic nature with high contact angle hysteresis below 30 °C and superhydrophobic nature with ultralow contact angle hysteresis above 36 °C.

Effect of cellulose whisker content on the properties of poly(ethylene-co-vinyl acetate)/cellulose composites.

The reinforcing effect of cellulose whiskers, produced from banana waste fibres, has been investigated using poly(ethylene-co-vinyl acetate) [EVA]/cellulose whisker composites. Cellulose whiskers, approximately 300 nm long and 30 nm wide, were obtained via a sulphuric acid hydrolysis method. The effects of the cellulose whisker loading on the thermal properties, mechanical properties and on the morphological features of the composites have been investigated.