(167i) Homogeneity of Liquid Metal Polymer Composites: Impact on Mechanical and Electrical Properties of Composites

Eutectic gallium-indium-tin (galinstan) droplets dispersed in a soft polymer matrix, such as polydimethylsiloxane (PDMS), form liquid metal polymer composites (LMPCs) that have tunable mechanical and electrical properties. In particular, galinstan-based LMPCs exhibit high relative permittivity and low modulus, making them ideal for use as deformable dielectric materials in pressure sensors and soft capacitors. Despite the abundance of literature on the effects of fillers in polymers, there has been little research on understanding the effect of filler homogeneity. Due to the greater density of galinstan as compared to the polymer matrix (6.44 g/cm³ compared to 0.97g/cm³), the droplets tend to settle before curing (particularly in low viscosity matrices), resulting in a spatially inhomogeneous distribution, which could potentially affect material behavior. To investigate the impact of liquid metal homogeneity, we introduced a rotating apparatus to achieve a uniform dispersion of the galinstan droplets in PDMS by gently rotating the samples at a constant speed. The work done here aims to explore the morphology, mechanical properties, and dielectric performance of LMPCs by varying their particle size, loading, and homogeneity. These findings highlight the importance of understanding the various factors that can affect the performance and longevity of LMPC-based devices, and the need for further research to optimize their manufacturing and application in various fields.