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Plenary Speakers

  • "Multiscale Modeling and Realization of Photo-responsive Polymers"
  • By Maenghyo Cho, School of Mechanical and Aerospace Engineering, Seoul National University, KOREA


Liquid crystalline polymers which contain photochromic chromophores can show macroscopic mechanical deformation under light irradiations. The light-induced shape change of the photo-responsive polymers (PRPs) comes from the trans-to-cis, or cis-to-trans isomerization of the mesogens, and it can be utilized to the microscale opto-mechanical actuation device. However, it is difficult to analyze and precisely predict the deformation because the theoretical approach requires a comprehensive knowledge of broad, interdisciplinary physical regimes that range from photochemical reaction kinetics to manipulating continuum scale deformations. Here, we develop a new multiscale model which integrates light input conditions, mesogen alignment, and continuum polymer deformations through sequential multiscale framework combining the DFT(density functional theory), MD(molecular dynamics), and continuum FE(finite element) method. In addition, the multiscale approach is applied to design the photo-mechanical behavior of the PRP nanocomposites with the consideration of the opto-mechanical coupling effect and microscopic interaction between the PRP matrix and fillers. This integrated framework can help to design the PRP and its composites.

Speaker Biography

Maenghyo Cho is professor of mechanical engineering of Seoul National University since 1999. He was the director of WCU Multscale Design Devision of Seoul National Univeristy from 2009 to 2015. Prof. Cho has focused on multiscale mechanics which connects different scale disciplines such as continuum mechanics, molecular dynamics and DFT calculations. Through the multiscale simulations, design and analysis of macroscopic/microscopic behaviors and scale-bridging techniques have been developed for various smart materials such as nanocomposites and lithium secondary battery materials. Recently, Professor Cho leads National Creative Research Initiative Center for design of photoresponsive deforming structures. He is interested in a multiphysics phenomenon in a photo-responsive polymer which causes mechanical deformations from light. The mechanism of this phenomenon is investigated by the multiscale/multiphysics analysis. Based on the mechanistic understanding, his group is working on the macroscopic light control and design for soft robot element. He has published more than 220 international journal papers and has served as editor or editorial board of of six international journals including IJSS and JOMMS.