An apparatus for measuring a material's photomechanical response

TL;DR

This paper presents a simple, cost-effective apparatus for measuring the light-induced shape change in materials, suitable for educational settings, using common components like a laser pointer, force sensor, and Arduino.

Contribution

It introduces an accessible experimental setup for characterizing photomechanical responses in materials, especially designed for high school and undergraduate laboratories.

Findings

Successfully used by students and teachers to measure liquid crystal elastomers

Provides a practical method for determining material parameters from photomechanical data

Demonstrates the apparatus's effectiveness in educational environments

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.