Prof. Ben Lear , The Pennsylvania State University
Rapid on-demand curing of thermally cured thermosets enabled by photothermal heating
Werner-Hartmann-Bau, Room 205/206 , Nöthnitzer Straße 66 , Dresden
Conventional curing of thermally cured thermosets requires the bulk-scale heating and cooling of the polymer and any substrate. While effective, the heating and cooling is rather slow and the spatial distribution of heat cannot be finely controlled. Both of these present problems for advanced manufacturing of objects from thermally cured thermosets. For instance, 3D printing of these thermosets at reasonable rates would require the ability to start and stop curing on the timescale of milliseconds. Curing of coatings of these thermosets on temperature-sensitive substrates, such as electronics or skin, would require the ability to heat only the micron scale film, and not its substrate.
Recent work from my research group has demonstrated that photothermal heating by nanoparticles can exceed the above requirements---providing nanosecond and nanometer precision in the distribution of heat. At the same time, this highly localized heat remains effective at driving thermally activated reactions. Indeed, through proper pairing of nanoparticles and light, we can achieve billion-fold rate enhancements of thermally activated chemical reactions---including the curing of thermally cured thermoset polymers. This talk will demonstrate this result and examine some of the kinetic and thermodynamic implications of this highly localized heat.
Biography: Prof. Lear was born in the state of California, earning a B.S. in biochemistry at UC Davis. During that time, he worked for Prof. Andrew Fisher at UC Davis and Dr. James Tucker at Lawrence Livermore National Laboratory. He then earned his M.S. and Ph.D. at UC San Diego, under the mentorship of Prof. Clifford Kubiak. There he studied electron transfer in mixed valence complex formed from oxo-centered trinuclear ruthenium clusters. He then performed postdoctoral studies under the mentorship of the late Prof. Malcolm Chisholm at The Ohio State University, where he continued to study electron transfer in mixed valence systems, this time focusing on quadruply bonded Mo and W units. In 2010, he joined the faculty at Penn State, where his interests currently lie in understanding the interplay between nanoscale materials and their chemical environments.