A P(VDF‐TRFE‐CTFE) Electroadhesive Clutch with Ultra‐Low Loading of TiO ₂ and Application in Adaptive Energy Absorption

Abstract The electroadhesive (EA) clutch is a variable‐stiffness device capable of high forces and having compact profile. Among clutch adhesive materials, P(VDF‐TRFE‐CTFE) is an attractive option due to facile processing, high force, and reasonable voltage. One of the drawbacks of P(VDF‐TRFE‐CTFE) clutches is long disengagement times. Here, TiO 2 nanofiller is presented as an innovative solution to reduce disengagement times by two orders of magnitude (from 14 to 0.13 s) while maintaining high EA stress and material elasticity. The decreased disengagement time is attributed to increased surface roughness imparted by TiO 2 , which reduces the friction coefficient by a factor of four. The flexibility and elasticity of the material are maintained by using low TiO 2 content (0.5–1.5%), which is important to allow for larger and more durable clutches. Due to the high forces now achieved by the EA clutch, the substrate yield strength and attachment strength are found to often be limiting factors rather than EA force. This paper analyzes and increases both these strengths. Finally, incorporating all these improvements, an EA clutch is applied as an active tether in vehicle airbags to control the deployed shape, and therefore the airbag shape can be optimized for different crash scenarios.