Scientific exploration of soft matter resulted in numerous technological advances, such as synthesis of a super-strong polymer Kevlar, liquid crystal displays (LCDs), development of new approaches to drug delivery, electrolytes, nano-templated materials, etc. The goal of this project is to explore the remarkable ability of soft matter to form a plethora of complex, well-organized functional structures and to understand the underlying principles by which the complex soft matter structures can be designed, produced, and controlled under both equilibrium and out-of-equilibrium conditions. The focus is on a broad class of biologically-compatible orientationally-ordered materials, the so-called lyotropic chromonic liquid crystals (LCLCs) and their composites with swimming bacteria, called living liquid crystals (LLCs). Complex structures of LCLCs and LLCs span a broad range of length scales, ranging from about 1 nm (the typical molecular size), to 10 microns (the size of a swimming bacterium), and further to the macroscopic scale, at which the structure can perform a useful function, such as microfluidic mixing or delivery of microscopic cargo (such as drugs). The project is a combination of modeling and experimental efforts connected to several emerging applications. In particular, the investigations will outline the potential of using the swimming ability of bacteria in constructing microscale systems for mixing and targeted delivery of microscopic cargo. The project will also elucidate the connections between LCLC and packing of DNA in viral capsids.
The principal research objectives of this project are to explore morphogenetic complexity of the equilibrium biphasic states of LCLCs that require an implicit balance between the interfacial and bulk energy and to understand the mechanisms of coupling between the out-of-equilibrium behavior of living LCs and anisotropic interactions between the constituents, including the interplay of bacterial activity, bacterial concentration, vector field of velocities, and orientational order. These goals will be achieved through controlled experiments and theoretical modeling. In the case of an equilibrium behavior, a challenge is in finding the shapes of orientationally- and translationally-ordered structures in confined geometries, exemplified by the nuclei of the chromonic hexagonal columnar phase in the isotropic environment. The complex shapes observed in experiments need to be described through minimization of both the internal elastic bulk energy and the anisotropic surface anchoring energy. In the studies of dynamics of LLCs the challenge is in simultaneous tracking of a number of scalar, vector, and tensor fields. The project aims to advance our ability to use mathematical algorithms for fast acquisition of big data characterizing dynamic systems with complex structure. It will also enhance predictive capabilities via the development and analysis of associated mathematical models.
