title: Enhancing the Scratch Resistance by Introducing Chemical Bonding in Highly Stretchable and Transparent Electrodes.
abstract: Stretchable transparent electrodes are key elements in flexible electronics and e-skins. However, existing stretchable transparent electrodes, including graphene sheets, carbon nanotube, and metal nanowire networks, weakly adheres to the substrate by van der Waals forces. Such electrodes suffer from poor scratch-resistance or poor durability, and this issue has been one of the biggest problems for their applications in industry. Here we show that, by introducing a Au-S bond between a Au nanomesh (AuNM) and the underlying elastomeric substrate, the AuNM strongly adheres to the substrate and can withstand scratches of a pressure of several megapascals. We find that the strong chemical bond, on the other hand, leads to a stiffening effect and localized rupture of the AuNM upon stretching; thus the stretchability is poor. A prestraining process is applied to suppress the localized rupture and has successfully improved the stretchability: electrical resistance of the prestrained AuNM exhibits modest change by one-time stretching to 160%, or repeated stretching to 50% for 25 000 cycles. This conductor is an ideal platform for robust stretchable photoelectronics. The idea of introducing a covalent bond to improve the scratch-resistance may also be applied to other systems including Ag nanowire films, carbon nanotube films, graphene, and so forth.
authors.affiliation: Department of Physics and TcSUH, University of Houston , 3201 Cullen Blvd, Houston, Texas 77204, United States.
authors.forename: Chuan Fei
authors.initials: CF
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences , Beijing, China 100190.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Physics and TcSUH, University of Houston , 3201 Cullen Blvd, Houston, Texas 77204, United States.
authors.forename: Lu
authors.initials: L
authors.lastname: Tang
authors.affiliation: Department of Physics and TcSUH, University of Houston , 3201 Cullen Blvd, Houston, Texas 77204, United States.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Physics and TcSUH, University of Houston , 3201 Cullen Blvd, Houston, Texas 77204, United States.
authors.forename: Zhifeng
authors.initials: Z
authors.lastname: Ren
keywords: Au−S bond; Scratch resistance; localized rupture; stretchability; stretchable transparent electrodes