Xinyu Wang - Geometry- and Topology-Programmed Functional Soft Materials Across Scales

Abstract: Topology provides a robust design principle whose winding number remains stable despite local damage, disorder, and fabrication imperfections. This seminar explores how a unifying topological winding principle can bridge two distinct domains of materials mechanics and enable precise functional control through tailored geometry.

First, I discuss liquid crystal systems in which carefully designed surface anchoring conditions and stimuli-responsive alignment patterns enable precise programming of disclination networks. We can accurately control the periods, positions, and charges of these defects across length scales. Such precision in defect control facilitates directed colloidal transport, sophisticated director-field sculpting, and reproducible material patterning. Second, I describe mechanically robust Maxwell lattices whose carefully engineered geometric distortions break mirror symmetry and introduce a directional bias into their mechanical response. This geometrically embedded ‘polarization’ allows controlled localization of stress, deformation, and fracture along predetermined boundaries, enabling protective structural designs or deliberate, controlled failure pathways. Such fracture guidance principles operate effectively across scales, from microfabricated lattice structures to metre-scale architected materials.

Building upon these frameworks, my ongoing and future research will further broaden the applicability of topology-guided design by integrating stimuli-responsive materials into topological lattice structures and advance the fundamental understanding and practical utility of topology-driven mechanics.

Biosketch:  Dr. Wang is a postdoc at the Univ. of Michigan Physics Department. Her Google Scholar page is here. She earned her PhD in Engineering in 2021 from School of Civil Engineering, Southeast University, China, working with Jian Feng & Prof. Jianguo Cai. As a PhD student, she also spent two years visiting UPenn, working with Randy Kamien. Her thesis was "Geometry and mechanics of origami and kirigami inspired metamaterials." From 2021-2023, she was a postdoctoral fellow at the Hong Kong Univ. of Science and Technology, working with Rui Zhang. Since 2023, she has been a postdoc at Univ. Michigan, working with Xiaoming Mao.