Direct-Ink-Write Printing and Electrospinning of Cellulose Derivatives for Conductive Composite Materials

The aim of this study is to realize the controlled construction and modulation of micro-/nanostructures of conductive composite materials (CCMs) in a facile way. Herein, interdigital electrodes are prepared by direct-ink-write printing co-blended inks made of ethyl cellulose and carbon nanotubes on cellulose paper. The cellulose nanofibers (CFs) are prepared by electrospinning cellulose acetate on to an aluminum foil, followed by deacetylation in NaOH/ethanol. All co-blended inks exhibit a typical non-Newtonian shear thinning behavior, enabling smooth extrusion and printing. The above electrodes and the conductive CF films with excellent thermal stability are assembled into a pressure sensor, which has a high sensitivity (0.0584 KPa^-1) to detect the change in external loading pressure. The obtained porous CFs film is further endowed with conductivity by in situ polymerization of polypyrrole (PPy), which are uniformly distributed on the CFs surface as particles; a triboelectric nanogenerator is constructed by using the CF@PPy film as a tribo-positive friction layer to achieve efficient energy harvesting (output voltage = 29.78 V, output current = 2.12 μA). Therefore, the construction of CCMs with micro-/nanostructures based on cellulose derivatives have essential application prospects in emerging high-tech fields, such as green electronics for sensing and energy harvesting.