Preparation of waterborne graphene paste with high electrical conductivity

Waterborne graphene paste with high conductivity is highly desired because it can avoid using harmful organic solvents. Herein, the paste with both good conductivity and adhesion on substrates was prepared. Hydrophilic graphene was made firstly by oxidizing weakly pristine graphene using a plasma. Then, the obtained graphene, dipropylene glycol methyl ether, glycol, glycerol, the copolymer of N-vinyl-2-pyrrolidone, and vinyl acetate (P(VP/VA)) were applied to fabricate the paste. The electrical conductivity of the paste-based patterns on polyimide substrates via screen-printing reached 1.34 × 104 s/m, and its adhesion reached 4B level. The paste is expected to have wide applications in making flexible conductive films.