Photoactuation in Nafion – Carbon Nanotube Bilayer Composites
Igor A. Levitsky, Peter T. Kanelos, Elana A. Viola, William B. Euler, Proceedings SPIE Nanosensing: Materials and Devices II, 2005, 6008, 600802-1 – 600802-6
Abstract
Single wall carbon nanotubes (SWNT)-nafion bilayer composites have a significant mechanical response (photoactuation) upon exposure to near infrared or visible light. The composites are formed as cantilevers of a thick nafion film (tens to hundreds of microns) coated with a thin SWNT film (one to ten microns). This configuration leads to a bending response upon light exposure. The wavelength dependence of the magnitude of the photoactuation corresponds to the absorption spectrum of semiconducting SWNTs. The thickness of each film in the bilayer affects both the magnitude of the bending and the rate of response. The mechanism of the photoresponse is proposed to be a result of the photocarriers migrating to the interface, attracting hydrated hydrogen ions from the nafion acid groups, which then induces swelling of the nafion substrate.