Use of chitosan to reinforce transparent conductive cellulose nanopaper

Abstract

Transparent conductive cellulose nanopaper (TCCNP) with excellent mechanical robustness and enhanced chemical stability offers the potential for diverse applications under severely humid conditions. Herein, the flexible freestanding TCCNP was successfully designed using TEMPO-oxidized nanocrystalline cellulose (ONC) crosslinked with chitosan (CS) as a fibrous skeletons and silver nanowires (AgNWs) as conductive networks. Due to their structural similarity, the CS molecules conjugated with ONC microstructures, leading to an effective crosslinking reaction between ONC and CS, thus effectively improving the mechanical properties of TCCNP in dry state and chemical corrosion stability of TCCNP in wet state. With the addition of CS, the mechanical stress of TCCNP (ONC/CS 70/30 w/w) increased from 14.5 MPa to 30.8 MPa, and the sheet resistance remained largely unchanged after immersion in strong acidic solution, alkali solution, alkaline salt solution, and neutral salt solution for 180 min. Furthermore, the well-constructed TCCNP with weight ratio of ONC/CS (70/30 w/w) achieved excellent transparent conductive performance with a low sheet resistance of 4.43 Ohm sq⁻¹ at high transparency (89.56%@550 nm). This discovery would open the way for further development of high-end flexible paper-electronics using the high performance polysaccharide-based TCCNP.