Electrochimica Acta, Vol.42, No.12, 1883-1894, 1997
Micro-Glassy Carbon Inks for Thick-Film Electrodes
A description follows concerning tile formulation of a model conductive ink system and the physico-chemical characterisation of thick films based on spherical glassy carbon micro-particles with low molecular mass polystyrene binding polymer. The study considers the effects of the carbon and polymer (C/P) mass ratio from 0.43 to 9.0 on the film surface morphology, electrical resistance and electrochemical properties. The surface structure of micro-glassy carbon films was examined by electron microscopy showing that surfaces have high polystyrene content when the C/P ratio falls below 2.3. Electrical resistances corresponding to dielectric materials are found for thick films prepared with inks containing 30% m/m or less carbon in the formulation. It was necessary to introduce the micro-spherical carbon to proportions beyond 60% m/m in order to reduce film resistances to less than 1 k Omega. The electrochemical properties of micro-glassy carbon films correlate with C/P ink values, where a transition is observed from insulator characteristics to random array microelectrode and ultimately a micro-porous macroelectrode.