Soft and Active Fluids

I am interested in understanding soft and living (or active) fluids. This categorisation of matter is relatively recent, but it offeres new and exciting physics that often leads to novel and unconventional engineering applications.

Mesoscopic structuring - much larger than the atomic scale, but smaller than the overall material scale - and the ability to respond to thermal energy are the hallmarks of soft matter, e.g. colloids, liquid crystals and gels. If the constituents of soft matter are living particles such as cytoskeletal elements or bacteria, it is referred to as active soft matter. Driven systems such as catalytic colloids and vibrated granular rods also come under the category of active matter. Depending upon the physical and chemical nature of the constituents the underlying microstructure of these materials may lead to complex macroscopic behaviours. Thus, properties such as fluidity, elasticity, surface effects and activity, are all key factors governing their dynamics. Often, the length scale of interest is in the nm − mm range that can make surface effects as important as bulk ones. On a larger length scale, flight of birds and bird flocks are interesting. Philosophical questions and evolutionary aspects are innate to living systems but I am interested in the application of the principles of fluid dynamics to soft and biological matter with a focus in finding novelty of materials and designing micromachines for medical and industrial applications.

Some pictorial results from my recent research are shown in the side bar.