PVC gel bio-inspired adhesives with variable modulus and its application in a gripper

Inspired by the microstructure of gecko’s toe, two kinds of polyvinyl chloride (PVC) gels with different modulus were poured on a silicon mold with micropillars, and then a bio-inspired adhesive with variable modulus was manufactured in this study. The adhesions of variable modulus and fixed modulus bio-inspired adhesives were tested, respectively, on a smooth glass and a printed circuit board (PCB) with different surface structures. The results show that PVC gel bio-inspired adhesives with variable modulus have many advantages compared with the fixed modulus bio-inspired adhesives. The adhesion of variable modulus bio-inspired adhesives on the rough PCB surface increased by 2–5 times, and due to the use of variable modulus of PVC gel, the surface micropillars can maintain high aspect ratio and flexible tips at the same time. Moreover, the use of PVC gel makes it easier to demold during the bio-inspired adhesives preparation. An adhesion-desorption device was made according to the movement of the gecko toes, and the PCB was successfully grasped.