Weihuan Zhao

Lightweight and multifunctional polymer composites are widely used in aerospace, automotive, and sensing applications. Piezoelectric materials enable the conversion between mechanical loads and electrical signals, which is critical in energy harvesting and sensing devices. However, limitations in the density and brittleness of piezoelectric materials exist and motivate development of advanced lightweight deformable composites. This study utilized polyvinylidene fluoride (PVDF)‐coated hollow glass microspheres (HGMs) as hybrid fillers to enable lightweight and sensing functionality in elastomer‐based composites. The HGMs were initially coated with PVDF using a bladeless mixing process followed by ultrasonication to ensure uniform coating. The coated microparticles were then integrated into a polydimethylsiloxane (PDMS) matrix and 3D‐printed. Electromechanical experiments, including cyclic compressive testing and dynamic demonstrations, revealed enhanced mechanical energy absorption and improved piezoelectric sensing performance. The soft composites exhibited a density reduction of up to 47%, and the 15 wt% PDMS–PVDF‐coated HGM composite achieved the highest piezoelectric voltage coefficient of 34.9 ± 1.9 mV m N ⁻¹ , approximately five times that of the PDMS–PVDF control without using the HGMs. The composites also exhibited filler‐dependent thermal properties. Drop‐impact and blast tests demonstrated observable electrical responses under dynamic loading. This suggests potential for the hybrid composites in lightweight sensing applications.

Fatty acids derived from waste cooking oil (WCO) are successfully processed as sustainable phase-change materials (PCMs) for thermal energy storage.

Transient three-dimensional (3D) heat and moisture transfer simulations were conducted to analyze the thermal performances of the entire phase change material (PCM) integrated into firefighters' gloves. PCM was broken down into several segments to cover the back and palm of the hand but to avoid finger joints to keep hand functions. Parametric studies were performed to explore the effects of PCM melting temperatures, PCM locations in the glove and PCM layer thicknesses on the overall thermal performance improvement of firefighters' gloves. The study found that PCM segments could extend the time for hand skin surfaces (areas covered or not covered by PCM) to reach second-degree burn injury (60 °C) by 1.5-2 times compared to conventional firefighters' gloves without PCM. Moreover, PCM segments could help mitigate the temperature increase on hand skin and glove surface after fire exposure.