Piezoresistivities of vapor‐grown carbon fiber/silicone foams for tactile sensor applications

• Published in: Polymer international Vol. 66; no. 3; pp. 418 - 427
• Main Authors: Guo, Chen, Kondo, Yasuo, Takai, Chika, Fuji, Masayoshi
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.03.2017; Wiley Subscription Services, Inc
• Subjects: Beads; Carbon fibers; Elastomers; Foaming agents; Foams; micro beads foaming agent; percolation threshold; Piezoresistivity; recovery time; Sensitivity; Silicones; tactile sensor; vapor‐grown carbon fiber
• ISSN: 0959-8103; 1097-0126
• DOI: 10.1002/pi.5275

Due to the growing demand for tactile sensors, the possibility of detecting an external uniaxial pressure by the piezoresistive measuring of a conductive filler/elastomer composite was investigated. A series of piezoresistive models are discussed. Novel highly sensitive piezoresistive foams with excellent elasticity were fabricated using vapor‐grown carbon fiber (VGCF), two‐component silicone elastomer and a new type of thermally expandable micro beads foaming agent to overcome the disadvantages of the silicone elastomer in the utilization of a tactile sensor. Deformations of the foams caused by uniaxial pressure were observed using scanning electron microscopy from cross‐sections. Effects of the VGCF and the foaming agent on the piezoresistivitiy were investigated. The piezoresistive mechanisms of the foams are discussed according to the measurements, and good fit was found between the theoretical calculations and the experimental piezoresistivity measurements. It is found that the addition of the micro beads foaming agent can improve the piezoresistivity of the VGCF/silicone foam and increase the sensitivity and repeatability for its application in a tactile sensor. © 2016 Society of Chemical Industry Novel highly sensitive vapor‐grown carbon fiber/silicone piezoresistive foams were fabricated. Introduction of a new type of thermally expandable micro beads foaming agent improves the piezoresistivity of the foams and increases the sensitivity and repeatability for tactile sensor applications.