title: Giant Surface Conductivity Enhancement in a Carbon Nanotube Composite by Ultraviolet Light Exposure.
abstract: Carbon nanotube composites are lightweight, multifunctional materials with readily adjustable mechanical and electrical properties-relevant to the aerospace, automotive, and sporting goods industries as high-performance structural materials. Here, we combine well-established and newly developed characterization techniques to demonstrate that ultraviolet (UV) light exposure provides a controllable means to enhance the electrical conductivity of the surface of a commercial carbon nanotube-epoxy composite by over 5 orders of magnitude. Our observations, combined with theory and simulations, reveal that the increase in conductivity is due to the formation of a concentrated layer of nanotubes on the composite surface. Our model implies that contacts between nanotube-rich microdomains dominate the conductivity of this layer at low UV dose, while tube-tube transport dominates at high UV dose. Further, we use this model to predictably pattern conductive traces with a UV laser, providing a facile approach for direct integration of lightweight conductors on nanocomposite surfaces.
authors.forename: Christian J
authors.initials: CJ
authors.lastname: Long
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Orloff
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Twedt
authors.forename: Thomas
authors.initials: T
authors.lastname: Lam
authors.forename: Fernando
authors.initials: F
authors.lastname: Vargas-Lara
authors.forename: Minhua
authors.initials: M
authors.lastname: Zhao
authors.forename: Bharath
authors.initials: B
authors.lastname: Natarajan
authors.forename: Keana C
authors.initials: KC
authors.lastname: Scott
authors.affiliation: Department of Mechanical Engineering & Materials Science, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Marksz
authors.forename: Tinh
authors.initials: T
authors.lastname: Nguyen
authors.forename: Jack F
authors.initials: JF
authors.lastname: Douglas
authors.forename: Jabez
authors.initials: J
authors.lastname: McClelland
authors.forename: Edward
authors.initials: E
authors.lastname: Garboczi
authors.forename: Jan
authors.initials: J
authors.lastname: Obrzut
authors.forename: J Alexander
authors.initials: JA
authors.lastname: Liddle
keywords: carbon nanotubes; cavity perturbation; conductivity; microwave; nanocomposite; scanning ion microscopy; ultraviolet