In-situ polymerization of pyrrole on cellulose nanofiber film: Structure characterization and electrochemical properties

Cellulose nanofiber (CNF) exhibits considerable potential for utilization in flexible electronic materials, primarily due to its exceptional mechanical properties and flexibility. In this study, an effective method was proposed to impart an electro-conductive layer to CNF-based films. Specifically, in-situ polymerization of pyrrole on the CNF film was developed via immersion and vacuum filtration processes, using pyrrole as a monomer and FeCl3 as an oxidant. A systematic investigation was conducted to assess how varying the molar ratio of FeCl3 to pyrrole influences the microstructure and properties of the resulting CNF/polypyrrole (PPy) composite films. We identified the optimal molar ratio of FeCl3 to pyrrole as 2:1. At this ratio, PPy was uniformly distributed on the surface of the CNF film, which facilitated the formation of effective conductive pathways. The electrical and electrochemical properties of the CNF/PPy composite film were further studied. The findings demonstrated that the maximum conductivity and specific capacitance of the composite film reached approximately 0.99 S/m and 138.26 F/g. Besides, the coating of PPy on the surface of CNF films apparently reinforced the thermal stability of the composite films. Overall, this work presents a convenient approach to fabricating CNF/PPy conductive films, which may hold significant potential for integration into wearable and flexible electronic devices. [Display omitted] •In-situ polymerization of pyrrole onto cellulose nanofiber film was developed.•Effect of ratio of FeCl3 to pyrrole on composite film properties was explored.•The thermal stability of composite film was improved due to the coating of PPy.•In-situ polymerization of pyrrole imparted desired conductivity to composite film.•Optimal ratio of FeCl3 to pyrrole on film electrochemical properties was confirmed.