Fabrication of a nanoscale 2D PEDOT pattern via the combination of colloidal lithography and vapor phase polymerization for application in transparent, highly sensitive bending sensors

Abstract

Recent advances in flexible, stretchable, and wearable electronics have necessitated the development of more diverse and complex device structures; high-resolution patterning strategies for conducting polymers are therefore urgently required to enable the fabrication of these devices. In this study, we report a nanoscale patterning strategy for conductive polymer films that utilizes a combination of vapor phase polymerization (VPP) and colloidal lithography. Here, hemispherical non-close-packed colloidal crystals are used as an effective lithographic mask for patterning oxidants on a substrate; subsequently, two-dimensional honeycomb-structured porous poly(3,4-ethylenedioxythiophene) (PEDOT) films are fabricated via VPP using the prepatterned oxidant. The resulting films closely resemble the morphology of the preceding oxidant structure; furthermore, the film porosity can be altered by adjusting the polymerization time. These patterned PEDOT films exhibit high transparency owing to the presence of voids, and high electrical sensitivity to bending stresses, which were concentrated in the narrow-patterned area. As the described fabrication methods are facile and reliable, this approach therefore provides an effective route for the fabrication of various conducting polymer frameworks in the micro- to nanoscale range.