title: Multiscale, Hierarchical Patterning of Graphene by Conformal Wrinkling.
abstract: This paper describes how delamination-free, hierarchical patterning of graphene can be achieved on prestrained thermoplastic sheets by surface wrinkling. Conformal contact between graphene and the substrate during strain relief was maintained by the presence of a soft skin layer, resulting in the uniform patterning of three-dimensional wrinkles over large areas (>cm2). The graphene wrinkle wavelength was tuned from the microscale to the nanoscale by controlling the thickness of the skin layer with 1 nm accuracy to realize a degree of control not possible by crumpling, which relies on delamination. Hierarchical patterning of the skin layers with varying thicknesses enabled multiscale graphene wrinkles with predetermined orientations to be formed. Significantly, hierarchical graphene wrinkles exhibited tunable mechanical stiffness at the nanoscale without compromising the macroscale electrical conductivity.
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical Engineering and Computer Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Won-Kyu
authors.initials: WK
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical Engineering and Computer Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Junmo
authors.initials: J
authors.lastname: Kang
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical Engineering and Computer Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Kan-Sheng
authors.initials: KS
authors.lastname: Chen
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical Engineering and Computer Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Clifford J
authors.initials: CJ
authors.lastname: Engel
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical Engineering and Computer Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Woo-Bin
authors.initials: WB
authors.lastname: Jung
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical Engineering and Computer Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Dongjoon
authors.initials: D
authors.lastname: Rhee
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical Engineering and Computer Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Hersam
authors.affiliation: Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Electrical Engineering and Computer Science, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Teri W
authors.initials: TW
authors.lastname: Odom
keywords: Graphene; conductive atomic force microscopy; hierarchical patterning; polystyrene; texturing; wrinkles