title: High-Resolution Mapping of Thermal History in Polymer Nanocomposites: Gold Nanorods as Microscale Temperature Sensors.
abstract: A technique is reported for measuring and mapping the maximum internal temperature of a structural epoxy resin with high spatial resolution via the optically detected shape transformation of embedded gold nanorods (AuNRs). Spatially resolved absorption spectra of the nanocomposites are used to determine the frequencies of surface plasmon resonances. From these frequencies the AuNR aspect ratio is calculated using a new analytical approximation for the Mie-Gans scattering theory, which takes into account coincident changes in the local dielectric. Despite changes in the chemical environment, the calculated aspect ratio of the embedded nanorods is found to decrease over time to a steady-state value that depends linearly on the temperature over the range of 100-200 °C. Thus, the optical absorption can be used to determine the maximum temperature experienced at a particular location when exposure times exceed the temperature-dependent relaxation time. The usefulness of this approach is demonstrated by mapping the temperature of an internally heated structural epoxy resin with 10 μm lateral spatial resolution.
authors.affiliation: Universal Technology Corporation, Materials and Manufacturing , 1270 North Fairfield Road, Dayton, Ohio 45433, United States.|Air Force Research Laboratory, Materials and Manufacturing Directorate (AFRL/RXCC) , Wright-Patterson Air Force Base, Ohio 45429, United States.
authors.forename: W Joshua
authors.initials: WJ
authors.lastname: Kennedy
authors.affiliation: Universal Technology Corporation, Materials and Manufacturing , 1270 North Fairfield Road, Dayton, Ohio 45433, United States.|Air Force Research Laboratory, Materials and Manufacturing Directorate (AFRL/RXCC) , Wright-Patterson Air Force Base, Ohio 45429, United States.
authors.forename: Keith A
authors.initials: KA
authors.lastname: Slinker
authors.affiliation: Air Force Research Laboratory, Materials and Manufacturing Directorate (AFRL/RXCC) , Wright-Patterson Air Force Base, Ohio 45429, United States.
authors.forename: Brent L
authors.initials: BL
authors.lastname: Volk
authors.affiliation: Air Force Research Laboratory, Materials and Manufacturing Directorate (AFRL/RXCC) , Wright-Patterson Air Force Base, Ohio 45429, United States.
authors.forename: Hilmar
authors.initials: H
authors.lastname: Koerner
authors.affiliation: Air Force Research Laboratory, Materials and Manufacturing Directorate (AFRL/RXCC) , Wright-Patterson Air Force Base, Ohio 45429, United States.|University of Dayton Research Institute , 300 College Park, Dayton, Ohio 45469, United States.
authors.forename: Trenton J
authors.initials: TJ
authors.lastname: Godar
authors.affiliation: Air Force Research Laboratory, Materials and Manufacturing Directorate (AFRL/RXCC) , Wright-Patterson Air Force Base, Ohio 45429, United States.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Ehlert
authors.affiliation: Air Force Research Laboratory, Materials and Manufacturing Directorate (AFRL/RXCC) , Wright-Patterson Air Force Base, Ohio 45429, United States.
authors.forename: Jeffery W
authors.initials: JW
authors.lastname: Baur
keywords: gold nanorods; polymer nanocomposites; structural composites; temperature sensing; thermal reshaping