Liquid crystals (LCs) are common in every household as display devices and are also widely used in scientific research as various optical components such as spatial light modulators, optical lenses, and sensors. The key characteristic of the high responsiveness of LCs under weak fields has been exploited in applications with mostly flat geometries. In addition to flat, thin layers of LCs, microfluidic approaches lead to spherical geometries such as droplets and shells. To this end, research is developing in many directions, from a fundamental understanding of the dynamics of topological defects on curved surfaces to topological defect-driven robots.
In the research group Physics of Soft Matter, Surfaces and Nanostructures, we cover a wide range of research topics in the field of soft matter, focusing especially on topological LC defects from generation to photonic applications and the active and passive dynamics of LCs. In particular, the self-shaping LC systems using microfluidics will be a research focus for this PhD position. Since the concept of self-shaping allows the shape of LC droplets to be changed at will into curved three-dimensional structures, it is expected to create new possibilities to study the topology, defects, and their transformation into actuators by converting them into LC elastomers. The experimental results will be closely coordinated with the theory and simulation group. Therefore, the PhD student will have a dynamic environment and will focus on experimental research on curved 3D LCs.
The PhD student will work on making curved LC structures of desired geometry based on published results using microfluidics and characterizing them using optical polarization microscopes, confocal laser scanning microscopes, and scanning electron microscopes to image the LC director and study actuation dynamics coupled to the topological defects and geometry.
Relevant publications:
- K. Peddireddy, S. Čopar, K. V. Le, I. Muševič, C. Bahr, and V. S. R. Jampani, Self-Shaping Liquid Crystal Droplets by Balancing Bulk Elasticity and Interfacial Tension, Proc. Natl. Acad. Sci. 118, e2011174118 (2021).
- V. S. R. Jampani, R. H. Volpe, K. Reguengo de Sousa, J. Ferreira Machado, C. M. Yakacki, and J. P. F. F. Lagerwall, Liquid Crystal Elastomer Shell Actuators with Negative Order Parameter, Sci. Adv. 5, eaaw2476 (2019).
- V. S. R. Jampani, D. J. Mulder, K. R. De Sousa, A.-H. Gélébart, J. P. F. F. Lagerwall, and A. P. H. J. H. J. Schenning, Micrometer-Scale Porous Buckling Shell Actuators Based on Liquid Crystal Networks, Adv. Funct. Mater. 28, 1801209 (2018).
- Y. Sasaki, V. S. R. Jampani, C. Tanaka, N. Sakurai, S. Sakane, K. V. Le, F. Araoka, and H. Orihara, Large-Scale Self-Organization of Reconfigurable Topological Defect Networks in Nematic Liquid Crystals, Nat. Commun. 7, 13238 (2016).