Computation and Theory of Soft Materials

Colloidal Self-assembly

Self-assembly of colloidal particles has enormous potential as a means of structure fabrication because of the scope for tuning the interparticle interactions. Anisotropy in colloidal interactions, now increasingly being achieved by either shape anisotropy or heterogeneous (patchy) surface chemistry, has greatly enhanced the prospect of complex three-dimensional structures being self-assembled. However, design rules for engineering self-assembly of colloidal building blocks into target structures are yet rather limited. We devise strategies for programmed self-assembly of colloidal particles in silico and elucidate the kinetics of assembly in close connection with contemporary experimental research. In recent years, our focus has been on programming self-assembly of colloidal open crystals – sparsely populated periodic structures comprising low-coordinated colloidal particles – often exploiting hierarchical self-assembly pathways. In particular, novel bottom-up routes to certain diamond-structured and related colloidal open crystals – much sought-after as colloidal photonic crystals – are established. We seek to push the frontiers of colloidal self-assembly.

Discotic Liquid Crystals

Self-assembly of liquid crystals is a remarkably rich phenomenon with emergence of partial long-range order to a variable degree. Of our particular interest are a spectacular variety of columnar phases, exhibited by discotic molecules, which typically have an aromatic core with peripheral aliphatic chains attached to it. Discotic liquid crystals, as a class of organic semiconductors in their self-assembled columnar phases, promise applications in opto-electronic devices, such as organic light-emitting diodes and photovoltaic cells. We seek to understand the photophysical properties of discotic molecules, their organisation in columnar phases and their charge transport properties in connection with their potential opto-electronic applications.

Topological Soft Materials

The concepts of topology, in either real or reciprocal space, play a critical role in certain soft materials, for example, liquid crystals, nematic colloids, and colloidal open crystals and empty liquids. We are interested in the study of such topological soft materials to develop fundamental understanding of their exotic behaviour and explore their novel applications. Our recent work has unravelled remarkable topological features of the liquid-liquid phase transition in tetrahedral liquids, and, specifically, in water. This new perspective of the liquid-liquid phase transition sets the foundation for further theoretical investigation in tetrahedral liquids, and, more generally, in network liquids from a topological perspective.