Engineering Liquid Crystalline Polymers for Biological Applications

Statement of Purpose: Large, bulky, power-hungry traditional mechanical actuators are poorly suited for small, biological applications such as medical devices. Shape changing polymers are an emerging class of actuators which can utilize environmental conditions to undergo large, complex shape changes. Liquid crystalline self-assembly is one promising strategy to program structural orientation and resulting actuation in polymeric materials. This molecular ordering can be spatially patterned, resulting in monolithic materials that undergo complex shape change. However, liquid crystal polymer networks are typically hydrophobic and only respond to stimuli that would be incompatible with biological environments, such as high temperatures and organic solvents. We have used two strategies to overcome these limitations: 1) engineering liquid crystal elastomers chemistry to respond near body temperature and 2) building gels from water-soluble, chromonic liquid crystals to respond to aqueous stimuli.