Cinnamate Functionalized Liquid Crystal Polymers for Elastomer Photoalignment

Liquid crystal elastomers (LCEs) are a type of material that combines the elastic properties of rubber with the anisotropic properties of liquid crystals. This material exhibits significant reversible shape changes when exposed to light or heat due to transition in the alignment of the liquid crystal units. LCEs could be useful in many types of applications including artificial muscles, robotics, and medical devices. One challenge with this type of material is expanding the processing options available for producing alignment. The goal for this project was to use cinnamate derivatives that were responsive to UV irradiation to create alignment in LCEs. Linear polymers were created using an aza-Micheal addition reaction. Chain extenders with a hydroxyl functionality were used to produce the polymers. Cinnamoyl chloride was then reacted with the hydroxyl groups to produce cinnamate functionalized liquid crystal polymers. FTIR was used to characterize the products. 300 nm UV light was used to photocrosslink the LCEs. UV-vis spectroscopy indicated that photo crosslinking between cinnamate pendants occurred. Future work will examine the extent of crosslinking and investigate processing steps that may lead to photoalignment using polarized UV light.