Lifetime-configurable soft robots via photodegradable silicone elastomer composites

TL;DR

This paper introduces a UV-degradable silicone elastomer composite for soft robots that can control their lifecycle and degrade on demand, enabling safer disposal and applications in hazardous environments.

Contribution

The study presents a novel UV-degradable silicone-based material and demonstrates its application in soft robots with integrated electronics for on-demand degradation.

Findings

The composite degrades under UV light via Si-O-Si backbone cleavage.

Decomposition kinetics increase with temperature, facilitating controlled degradation.

A gaiting robot with integrated sensors was successfully fabricated using the composite.

Abstract

Developing soft robots that can control their own life-cycle and degrade on-demand while maintaining hyper-elasticity is a significant research challenge. On-demand degradable soft robots, which conserve their original functionality during operation and rapidly degrade under specific external stimulation, present the opportunity to self-direct the disappearance of temporary robots. This study proposes soft robots and materials that exhibit excellent mechanical stretchability and can degrade under ultraviolet (UV) light by mixing a fluoride-generating diphenyliodonium hexafluorophosphate (DPI-HFP) with a silicone resin. Spectroscopic analysis revealed the mechanism of Si-O-Si backbone cleavage using fluoride ion (F-), which was generated from UV exposed DPI-HFP. Furthermore, photo-differential scanning calorimetry (DSC) based thermal analysis indicated increased decomposition kinetics at increased temperatures. Additionally, we demonstrated a robotics application of this composite by fabricating a gaiting robot. The integration of soft electronics, including strain sensors, temperature sensors, and photodetectors, expanded the robotic functionalities. This study provides a simple yet novel strategy for designing lifecycle mimicking soft robotics that can be applied to reduce soft robotics waste, explore hazardous areas where retrieval of robots is impossible, and ensure hardware security with on-demand destructive material platforms.