Chemical-responsive curved actuator using PDMS/Ecoflex composite bilayer for rapid detection of chemical solvent leakage

Abstract

This study demonstrated a fabrication method for a polymer bilayer actuator (PBA) by using an interfacial reaction between polydimethylsiloxane (PDMS) and Ecoflex. Both materials are silicone-based elastomers that exhibit similar Raman spectra. However, the Si–CH3 symmetric rocking bonds present in PDMS have been found to interact at the interface with Ecoflex. Depending on the curing order of the two materials, the interfacial bonding strength between the two materials can be adjusted. In addition, flat samples change into curved samples due to the interactions of the two materials. By utilizing these properties, a chemical solvent detection device using a PBA composed of PDMS and Ecoflex, which have different reactivities to chemical solvents, was demonstrated. This can smoothly detect solvent volumes up to 10 µL with < 1 s of initial reaction time. The maximum force caused by the bending motion of the actuator was 4.869 and 3.726 mN with 10 µL of acetone and isopropanol, respectively. Furthermore, an alarm system capable of detecting small amounts of solvent and signaling danger was successfully developed, and its performance was evaluated. Moreover, a chemical-resistant gripper application using PBA was also demonstrated. These results demonstrated the utilization of PBA for practical applications in hazardous chemical-leakage environments.