text: The PECT effect was first reported by Dr. F Lincoln Vogel in 1981 when studying how intercalation voltages could be used to provide an actuation force in graphitized carbon fibres. The research used sulphate (SO) ions from sulfuric acid to intercalate into the microstructure of carbon fibers, forming graphite intercalation compounds (GICs). It was hypothesized that an axial strain of up to 2% should be possible, however only 0.2% was observed due to experimental limitations.
  The effect is often explained by the theories of Larché and Cahn who derived mathematical formulations for the equilibrium relationships between the electric potential, chemical potential, and mechanical stress in solid materials. In summary the theory states that solid materials under mechanical stress undergo a change in chemical potential, which in turn affects their electrical potential.