Title| Shape-Shifting and Dissipating Liquid-Crystalline Elastomers for 3D Printing and Biomedical Applications

Speaker| Associate Professor Christopher M. Yakacki,  University of Colorado Denver.

Date| 4 December 2017 (Monday)

Time| 1400 – 1500

Venue| Think Tank 22, Building 2, Level 3 (2.311)



Liquid-crystalline elastomers (LCEs) are a class of stimuli-responsive and active materials known for their unique mechanical and optical properties. These materials can demonstrate a large magnitude (~700%) of thermally-reversible shape change and actuation due to the coupling of liquid-crystalline order and network elasticity.  As a result, LCEs have been proposed for a myriad of sensor and actuator applications, such as artificial muscles, tunable iris lenses, and soft robots. While promising materials, the practical application, scalability, and accessibility of main-chain LCEs remain a limiting barrier in the widespread use of LCEs. This presentation will present a novel two-stage thiol-acrylate Michael addition-photopolymerization reaction for scalable synthesis of main-chain LCEs and a programmable single-liquid crystal monodomain. The structure-property-performance relationships of this system is presenting in light of creating tailorable materials. Studies showing control over the actuation temperature, dissipation profile, and liquid-crystalline order are presented. This chemistry and method can be combined with 3D-printed structures to create soft robots as well as directly printed to create anisotropic structures. Lastly, this presentation will cover how the spatio-temporal control of this reaction can be used to create highly mechanically anisotropic, shape-changing, and shock absorbing materials for previously unexplored biomedical applications.



Dr. Yakacki received his BS, MS, and PhD from the Department of Mechanical Engineering at the University of Colorado Boulder in 2004, 2004, and 2007, respectively. After graduating, he served as Principal Scientist for MedShape, Inc. in Atlanta, GA, a biomedical device company he helped co-found. He was awarded over $1M in Small Business Innovation Research (SBIR) grants at MedShape, and helped clear the first shape-memory polymer biomedical devices through the United States Food and Drug Administration (FDA). Dr. Yakacki became an Assistant Professor in the Department of Mechanical Engineering at the University of Colorado Denver (CU Denver) in 2012. Since joining the department, he has been awarded an NSF CAREER award, an NIH/NIAMS R21 award, a State of Colorado Bioscience Discovery Evaluation Grant (BDEG), an NSF I-CORPS award, and ARO research award. Dr. Yakacki has published 43 peer-reviewed publications, 3 book chapters, and has been awarded over $1M in research grants at CU Denver. Dr. Yakacki currently serves as the EASPHD Program Coordinator for his department. In January 2018, Dr. Yakacki will start his sabbatical to lead a start-up company, Impressio, to commercialize novel LCE devices).