Polymers are regularly used as thermal insulators for everything from keeping beverages hot to keeping sensitive electronics cool.

In some cases, polymers can even be used as thermal conductors to enable efficient heating or cooling.

Discovery of polymers that can be optically triggered to quickly switch between thermally conducting and insulating states will open up entirely new opportunities in thermal engineering," explained Paul Braun, a materials science and engineering (MatSE) professor and director of the Illinois Materials Research Laboratory.

The particularly notable finding in this study is the fast, reversible 3-fold change in thermal conductivity associated with the phase transition," explained Jungwoo Shin, a MatSE Ph.D. student at Illinois.

The thermal switching polymer developed by the Illinois research team demonstrates a powerful control of the thermophysical properties of a polymer in response to light.

This ability originates from a photo-responsive molecule,azobenzene, which can be optically excited by ultraviolet (UV) and visible light.

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