Model Polymer System for Red Light Activated Azobenzene Molecules

Photomechanical materials are light responsive substances that can be repeatedly and wirelessly actuated. These materials have potential for applications such as soft actuators in microfluidic or biomedical devices. Previous studies have observed macroscopic deformation in polymers by varying location, polarization, wavelength, and intensity of light on polymers containing the light sensitive molecule, azobenzene. While past work in this area has been beneficial, azobenzenes are typically only triggered when exposed to UV or blue-green light. These wavelengths of light are harmful to biological tissue and degrade polymers after long periods of exposure. This study’s objective was to create a polymer system in which a red or NIR activated azobenzene could be incorporated. Multiple model systems were created with methyl methacrylate, butyl acrylate, and styrene as monomers, while standard off-the-shelf azobenzenes were used to create the photomechanical response. Results indicate that it is possible to cause the polymer film to move either towards or away from a blue-green light source (λ= 450nm). Further testing must be done in order to determine if the response is caused by light actuation or thermal actuation. In the future, studies will also be conducted to generate a more consistent photoresponsive film for integrating red/NIR absorbing azobenzenes