Large-Area Patterning of Polyaniline Film Based on <i>in Situ</i> Self-Wrinkling and Its Reversible Doping/Dedoping Tunability

Abstract

Here we report a simple one-pot yet robust approach to fabricate large-scale wrinkle patterns with reversible acid-doping/base-dedoping tunability. A novel swelling-induced self-wrinkling mechanism is responsible for the <i>in situ</i> growth of wrinkled polyaniline (PANI) film on polydimethylsiloxane (PDMS) substrate. The spontaneously formed wrinkles with controlled microstructures such as the wavelength, spatial orientation, and location have been well regulated by PANI film thickness (via polymerization time and monomer concentration) and PDMS substrate modulus as well as the boundary conditions imposed by the substrate. The results indicate that the <i>in situ</i> self-wrinkling is highly desirable for patterning PANI film over large areas with the instability-driven morphologies, even in the case of curved surfaces employed. Interestingly, taking advantage of the swelling/deswelling capability via the unique acid doping/base dedoping of PANI, we have further realized unprecedented reversible modulation between the wrinkled and dewrinkled states. The involved physics underlying the complicated <i>in situ</i> self-wrinkling and the reversible doping/dedoping tunability has been revealed