An apparatus for measuring a material's photomechanical response

Abstract: Please find the final and published version of the manuscript using this citation: E. Bernhardt, et. al, "An apparatus for measuring a material's photomechanical response", American Journal of Physics, 86, 14 (2018) This paper describes a simple and inexpensive apparatus for measuring the light-induced shape change of a material, which can be implemented in a high school or undergraduate laboratory. The key components are a laser pointer to actuate the material, a force sensor from an inexpensive jeweler's balance to measure the response, an Arduino for data acquisition and a means for mechanically mounting the components. The apparatus described here was used by high school students and teachers in a summer program to characterize liquid crystal elastomers. The theory of the photomechanical response is used to interpret the data, from which the material parameters are determined.