Complex fluids such as liquid crystals, polymer blends, surfactant solutions and emulsions are routinely subjected to shear flow during manufacturing and processing. But it is difficult to predict the effects of shear flow on the microscopic structure of a complex fluid. In the case of stirring an emulsion, the flow results in mixing. In liquid crystals, shear induces alignment, and can even induce non-equilibrium phase transitions. For surfactant solutions, shear flow can lead to de-mixing, inducing a co-existence between two phases with different micro-structures, and therefore different viscosities. The calculation of a fluid's macroscopic properties and phase transitions, from a knowledge of microscopic interactions, is usually accomplished by statistical mechanics, via the application of Boltzmanns' law. But Boltzmann's law is valid only at equilibrium. There has traditionally been no standard theoretical route for the prediction of transitions and micro-structure under flow. Recent developments in the theory of driven steady states and non-equilibrium applications of information theory have opened up new possibilities for the detailed investigation of shear flow in complex fluids. The student will investigate idealized models of interacting particles under shear, and develop methods for constructing non-equilibrium statistical ensembles and numerical algorithms. The project will involve both theoretical and computational elements. The student will work within the Polymers and Complex Fluids group, which has strong theoretical and experimental elements, allowing for lively collaborations, and experimental testing of theoretical predictions.
Informal enquiries are welcome, and should be directed to Dr. R. M. L. Evans (phyre@irc.leeds.ac.uk) or myself
Please look here for application forms and further information.
Here is Dr. Evans' home page, which has more information on the project.
The Leeds Polymer & Complex Fluids group has a wide range of theoretical and experimental interests in complex fluids, and has contacts with many academic and industrial groups abroad and in the UK.