RPLab

Laboratory for Microstructural Mechanics of Complex Fluids
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We are interested in firstly understanding how the microstructure and dynamics of complex fluids determines their macroscale behaviour, and then in translating that understanding into novel and useful applications.

Our current focus is on the behaviour of living matter at the cellular and sub-cellular levels, as exemplified by suspensions of motile bacteria, or by the membrane-cytoskeletal assemblage within eucaryotic cells. Such "active" materials are collectives of entities that constantly push and pull their neighbours, and are known for their ability for self-organization (e.g. pattern formation in surface colonies of motile bacteria; cytoskeletal reorganization in filopodal or lamellipodal cell migration, endocytosis, cell-divison). Can we describe the macroscale behaviour of such living collectives by thinking of them as continuum materials, governed by rheological equations of state? Exciting new developments indicate that this may be the case. If so, how can we relate the deformation and stresses in such materials to interactions at the microscale between the individual entities that make up these fluids? Further, can we understand how these "very smart fluids" regulate their own mechanics to achieve controlled motion? And therefore, can we build soft artificial microbots that can swim or crawl on their own, or soft microreactors whose walls can open and close to transport material in and out? We seek to answer these questions by combining ex- and in-silico experiments with mathematical modeling.

We also explore the dramatic changes in fluid behaviour in complex flows when tiny amounts of flexible polymers are dissolved in it. Polymer additives are used to lend a certain springiness to the solution. This elasticity is useful in a wide variety of applications such as turbulent-drag reduction, ink-jet printing, agricultural spraying, fuel injection etc. We use a combination of experiments, modeling and simulations to study the links between polymer chemistry and architecture on the one hand, and the fluid dynamics of dilute polymer solutions in these applications on the other.

We work closely with the Molecular Rheology group at Monash University

Contact: Dr. Prabhakar Ranganathan Department of Mechanical & Aerospace Engineering Monash University Rm. no. 123, Bldg. 31 Clayton VIC - 3800 Australia Ph: +613 9905 3480 Email: prabhakar.ranganathan@monash.edu