Photothermal heating at the nano and meso scales within polymer nanocomposites

Metal nanoparticles strongly absorb specific wavelengths of visible/infrared light with no radiative relaxation by which to release this energy. As a result, the absorbed energy is efficiently converted to local heat (a photothermal effect [1]). With an effective cross-section of up to 10 times its physical size, each particle acts as a "super-sized" absorber even when embedded within a material environment, resulting in dramatic heating [2,3] originating at the particles. Polymer nanocomposites containing metal nanoparticles can then be probed [4] and altered by applying internal heat at nano- and meso- length scales. I'll discuss our recent studies [5] utilizing this effect, including internal annealing to increase crystallinity fraction in both films and nanofibers of poly(ethylene oxide) [6], in-situ curing of epoxy, and intentional degradation of starch-poly(ethyl cyanoacrylate) composites. The talk will highlight the unique features of a photothermal approach, such as the ability to couple energy quickly (as light) into low thermal conductivity environments and possible changes in thermal conductivity at the particle-polymer interface. [1] S. Maity et al., \textit{Polymer} \textbf{52}, 1674 (2011). [2] S. Maity et al., \textit{Adv. Funct. Mater.} \textbf{22}, 5259 (2012). [3] S. Maity et al., \textit{Part. & Part. Sys. Char.} \textbf{30}, 193 (2013). [4] S. Maity et al., \textit{Nanoscale} \textbf{6}, 15236 (2014). [5] D. B. Abbott et al., \textit{Macrom. Chem. & Phys.} \textbf{215}, 2345 (2014). [6] V. Viswanath et al.,\textit{Macromolecules} \textbf{ 46}, 8596 (2013).