Patterning three-dimensional (3D) structure into two-dimensional (2D) graphene is important for applications in flexible electrodes, stretchable electronics and energy storage devices. We have demonstrated a conformal wrinkling process that can generate hierarchical graphene architectures. Multi-scale graphene patterning is achieved by sandwiching a soft fluoropolymer skin layer between as-synthesized graphene and pre-strained polystyrene substrates. Because the thickness of the skin is controllable with one-nanometer accuracy, the resulting graphene wrinkle wavelengths can be tuned from tens of nanometers to several micrometers. Moreover, since graphene wrinkles only occur on the skin layer regions, patterning the substrate with different skin thicknesses results in multiscale graphene wrinkles with different wavelengths and orientations side-by-side. In this manner, the mechanical stiffness of graphene can be locally tuned as a function of wrinkle wavelength while maintaining consistent electrical conductivity. With rational design of the hierarchical structuring, conformal wrinkling allows exquisite tailoring of graphene for advanced applications, such as sensors and nano-bio interfaces, where tunable mechanical properties and surface interactions are necessary.
Multiscale, Hierarchical Patterning of Graphene by Conformal Wrinkling
by Teri Odom | Oct 11, 2016 | Featured Research