Solvent resistance of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) treated cellulose nanofiber film for flexible electronics

The ability to resist various solvents is critical during the preparation of flexible electronics on cellulose nanofiber (CNF) films via solution-phase coating process, as solvent cleaning steps are performed before and after the device fabrication, and solvent-based functional inks are used during the production process. However, literature on the solvent-resistance of CNF films is scarce. In this study, we investigated the solvent resistance of 2,2,6,6-tetramethylpiperidine-1-oxyl treated CNF films (TTCFs) in terms of solvent inertness and barrier properties against solvents by separately immersing the films in seven different organic solvents. As a result, the TTCFs exhibited excellent solvent resistance with no obvious change in their optical and mechanical properties, as well as dimensional and thermal stability after solvent treatment for 24 h. Furthermore, a novel method based on color-fading of thermal paper was first proposed to evaluate the barrier properties of the TTCF against diverse solvents. By applying a CNF film with a minimum coating weight of 3.94 g/m2, the thermal paper acquired the desirable barrier properties. The superior anti-solvent performance, along with the excellent stability, paves the way for the fabrication of next-generation green electronics on biodegradable and renewable TTCFs.