A Method of Manufacturing Highly Conductive Composite Materials by Coating Surfaces of Nonconductors with Fine Particulate Conductive Substances

Summary.

 A widely applicable aqueous dip-coating process termed substrate induced coagulation (SIC) suitable for coating various types of substrates (e.g. polar and unpolar polymers, inorganic glasses, metals) with fine particulate materials (e.g. carbon blacks, small particle size SiO₂ or TiO₂) has been developed. This process is based on the interaction of a conditioner (water soluble polymers or polyelectrolytes, e.g. proteins, polyvinylalcohols, polyacrylates with low charge density) which is adsorbed on the substrate with a surfactant-stabilized dispersion containing some additional electrolyte. Employing dispersions of conductive particles, the resulting coatings can be used as a conductive starting layer for electroplating. Such layers are fairly rinse-proof and may be applied in the metallization process of through holes in printed wiring boards or for the production of highly conductive composite materials from coated particles. SIC has also been used to improve the distribution of carbon in composite battery electrodes such as MnO₂/C.