Controllable synthesis of anisotropic liquid metal-polycaprolactone composites with high viscosity and superior degradability

Abstract

Composite materials hold great promise in wearable implant devices, self-healing materials, and electromagnetic shielding materials, due to the merits of flexibility, impact resistance, and low cost. Herein, a novel, conductive, anisotropic, and environmentally degradable liquid metal-polycaprolactone composite material was controllably prepared for the carrier of electronic devices, using polycaprolactone (PCL) polymer as the base, liquid metal (LM) particles with diameters of 400–500 µm as the functional droplet. By regulating the composition and ratio of LM and PCL, three composite materials were successfully obtained: LM-PCL (10 wt%)− 1, LM-PCL (20 wt%)− 2, and LM-PCL (40 wt%)− 3. However, among the above three materials, only LM-PCL-1 was found to be an anisotropic material with conductivity on one side and insulation on the other. Many stretchable fibers could be prepared by cooling and extruding LM-PCL-1 in water. Besides, the more PCL content in LM-PCL, the higher the hardness. Finally, the degradation effects of LM-PCL in acid, alkali, and neutral aqueous solutions were systematically investigated. The degradation rate of LM-PCL was the fastest in the concentration of 10 mol/L HCL. LM in the composite material could be recycled by centrifugation. The prepared LM-PCL composites could be widely used in microelectronics and sensor parts.