Electrochemical and printable properties of polydopamine decorated carbon nanotube ink

Printing technique is a promising technology to fabricate micro-supercapacitors. The key point to realize a printed micro-supercapacitor is to find a suitable and conductive ink. Carbon nanotubes (CNTs) are regarded as an ideal candidate for this purpose. However, CNTs are not easy to dissolve in water homogeneously due to the intrinsic aggregation to bundles. In order to solve this problem, herein, polydopamine modification strategy was developed to synthesis CNTs based ink with enhanced printable properties (e.g., the hydrophilicity, dispersibility and long-term stability). After coating proper polydopamine on the surface of CNTs, the hydrophilicity, dispersibility and long-term stability of CNT ink were significantly improved. Compared with pure CNT ink, only a negligible reduction of the specific capacitance of CNT can be observed. Our work here provides new insights to design and synthesize advanced printing ink, and also would accelerate the practical applications of printing technique in printed electronics.