Capacitance measurements study of the carbon fibre surface

Abstract

The double layer capacity at the carbon-fibre/electrolyte (potassium chloride) interface increases with treatment time but less rapidly than the surface area, contradicting the data of Kalnin who reported that the capacity increases more rapidly than the surface area. This disagreement indicates the significant influence of the nature and amount of surface groups present. The dipole moments of the surface groups increase fibre wetting in aqueous solutions and, therefore, the effective fibre/electrolyte surface area increases. The capacity is significantly decreased by removing the surface groups.