Processable polyaniline suspensions through in situ polymerization onto nanocellulose

Polyaniline-based aqueous suspensions containing a variety of polyaniline (PANi) contents ranging between 5 and 80 wt.% have been successfully developed through in situ polymerization of aniline in a nanocellulose suspension. Herein, a suspension of high aspect ratio nanofibrillated cellulose (NFC), which was prepared by combining an enzymatic hydrolysis and mechanical shearing, was utilized as platform, stabilizer, and reinforcement for PANi deposition during the in situ synthesis. As a demonstration for the good processability, NFC/PANi composite paper-based materials which exhibited good mechanical properties and high conductivity were easily fabricated from these NFC/PANi suspensions. The NFC/PANi composite paper exhibits a percolation threshold of electrical conductivity of 4.57 vol.% of PANi content, at which the corresponding conductivity was measured to be 2.6 × 10−5 S cm−1, which is well above the antistatic criterion of 10−8 S cm−1. Remarkably, at the percolation threshold, the mechanical strength of the NFC/PANi composite paper is as same as that of neat NFC. This work provides a straightforward procedure for fabrication of PANi-based suspensions and flexible paper-like materials with good mechanical and electrical properties, which may find potential applications in flexible electrodes, antistatic coatings, and electrical conductors.