Bending Stress Dependent Electrical Resistivity of Carbon Fiber in Polymer for Health Monitoring System

Influences of compressive and tensile stresses on an electrical resistivity of carbon fiber in polyvinyl acetate polymer on bending test are studied as a basic research to develop high sensitive stress sensors. It is confirmed that a compressive stress of less than 0.3 GPa on bending test reversibly decreases the electrical resistivity of carbon fiber due to enhancement of the density of state of π bonding electron. A tensile stress of less than 0.3 GPa on bending test also decreases the electrical resistivity of carbon fiber, reversibly, because of decreasing the density of electron scattering sites.