Graphene nanosheets as ink particles for inkjet printing on flexible board

• Stable ink containing graphene nanosheets for inkjet printing is prepared.
• The ink is prepared by sodium n-dodecyl sulphate and ammonia.
• Conductive feature on a flexible polyimide film is fabricated by printing this ink.
• The conductivity of the sintered film can be 121.95 S m−1.

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 °C can effectively lead to the elimination of excess SDS on the GNSs and increase the CC 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.