Bioinspired Superhydrophobic and Durable Octadecanoic Acid/Ag Nanoparticle-Decorated Rubber Composites for High-Performance Strain Sensors

Electrically conductive elastomer composites (CECs) show potential applications in wearable strain sensing. However, it remains a great challenge to develop a facile and versatile method to prepare multifunctional CEC strain sensors integrating superhydrophobicity, high electrical conductivity, strong interfacial adhesion, and excellent durability. Inspired by the surface superhydrophobicity of taro leaves, herein, a highly conductive and fluorine-free superhydrophobic CEC is fabricated by a novel "ion reduction and simultaneous molecule phase separation" method. Octadecanoic acid (OCA) with low surface energy can not only impart the CEC with superhydrophobic property and corrosive resistance but also greatly enhance the interfacial interaction between AgNPs. The obtained CEC shows high conductivity (21.9 S/cm) and superhydrophobicity (with a contact angle of 152.6 degrees). The superhydrophobic CEC with excellent corrosion resistance can be used as strain sensors and shows large working strain and sensitivity (with a gauge factor of 61.8 at the strain range of 80-120%) and excellent cycle stability. Also, it can detect human motions in both ambient and underwater conditions, showing promising applications in underwater wearable electronics.