WFU Department of Physics Wake Forest University

 

Wake Forest Physics
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WFU Physics Colloquium

TITLE: Embedded metal nanoparticles as light-driven, localized heaters within polymeric solids

SPEAKER: Professor Laura I. Clarke ,

Physics Department
North Carolina State University

TIME: Wednesday September 18, 2013 at 4:00 PM

PLACE: Room 101 Olin Physical Laboratory


Refreshments will be served at 3:30 PM in the Olin Lounge. All interested persons are cordially invited to attend.

ABSTRACT

Metal nanoparticles strongly absorb specific wavelengths of visible/infrared light with no (or only a very weak) radiative relaxation by which to release this energy. As a result, the absorbed energy is efficiently converted to local heat (a photothermal effect). 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 transparent material environment, resulting in dramatic heating originating at the particles. Thus, with spatially-uniform illumination, one can metaphorically reach inside the sample and apply heat to pre-selected subsets (e.g., causing them to dramatically change properties due to actuation, cross-linking, crystallization, or chemical reaction) without heating the surface or strongly affecting the remainder of the material. This is particularly true for solid, polymeric samples where moderate light intensities can result in dramatic heating. I'll discuss recent results demonstrating selective heating, measurement of average internal sample temperatures close to and far from particles, and how this temperature gradient changes as a function of irradiation intensity.



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100 Olin Physical Laboratory
Wake Forest University
Winston-Salem, NC 27109-7507
Phone: (336) 758-5337, FAX: (336) 758-6142
E-mail:
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