Graphene nanosheets as ink particles for inkjet printing on flexible board

Stable ink containing highly dispersed graphene nanosheets (GNSs) for inkjet printing on polyimide (PI) film has been successfully prepared by the adsorption of sodium n-dodecyl sulphate (SDS) and adjusting the pH value to 10 by ammonia. Conductive features on a flexible PI film were fabricated by inkjet printing the stable ink directly on a substrate. With higher number of printing cycles, the loading weight of GNS on PI film showed a linear increase up to printing 200 times, when the conductivity reached the saturation value of 6 S m(-1). Sintering the printed GNS at 400 degrees C can effectively lead to the elimination of excess SDS on the GNSs and increase the C=C content. The data provided by a four-point probe show that the conductivity of the sintered film can be improved to 121.95 S m(-1). (C) 2013 Elsevier B.V. All rights reserved.