PhD Projects
Here are some suggested PhD projects. If you have
any questions about these, or related ideas, feel free to contact me,
p.d.olmsted@leeds.ac.uk .
Application forms and information can be obtained from
Mrs Maureen Thompson, m.thompson@leeds.ac.uk .
PHASE SEPARATION IN LIPID MEMBRANES (theory)
Lipid bilayer membranes are the most common membranes in living
organisms. While the physics and phase behavior of simple model
membranes has been well-studied for the last decade, only recently have
physicists and biophysicists realized that the rich family of different
lipids and proteins that inhabit membranes have crucial effects on
membrane function. The prospective student will study the dependence
of membrane shape and function on lipid and protein composition; this
may be performed in close collaboration with experimentalists at Leeds
studying the mechanism of general anaesthesia.
BIOPHYSICS OF MUSCLE (theory)
Muscle is extraordinarily well-designed machinery, comprising several
biopolymers organized in different forms to coordinate stretching and
supply force. With the advent of single-molecule measurements and
characterization methods there is now sufficient data to obtain an
understanding of the physics behind muscle. The prospective student
will use concepts from statistical mechanics and polymer physics to
analyze the physical processes behind muscle and other biopolymer
systems. This is a theoretical project, and will involve close contact
with experimentalists in the Biomedical sciences at Leeds; techniques
will include analytic theory and simulations.
RHEOLOGY OF SIDE-CHAIN LIQUID CRYSTAL POLYMERS (theory)
Side-Chain liquid crystal polymers comprise a flexible backbone and stiff
"teeth"; these materials have a wide variety of practical uses due to the
combination of polymer properties, enabling strength and processability,
and liquid crystalline nature, which allows for fine-tuned optical
properties. Recently, many groups have been studying the effects of
flow on these materials, and it is apparent that current theories of
polymeric and liquid crystalline systems do not adequately describe
these materials. The prospective student will study the dynamical
theory of side-chain liquid crystal polymers, involving hydrodynamics
and statistical mechanics.
FLOW-INDUCED PHASE TRANSITIONS IN COMPLEX FLUIDS (theory or experiment)
A wide variety of complex fluid solutions (polymer solutions,
surfactant solutions in lamellar or threadlike "micellar" structure,
colloidal suspensions) can be induced to phase separate in flow. Such
phase separation or induced phase transitions can induce dramatic flow
responses, such as shear thinning (spurt) or shear thickening (jamming).
Experiment: The prospective student will study experimental aspects of
these transitions, in surfactant systems. The idea will be to study
the kinetics of phase transformations between different flow-induced
phases in lamellar phases of surfactant solutions. Theory: the student
will study models of increasing complexity for the dynamics of complex
fluids, with a goal of trying to understand time-dependent oscillatory
or chaotic states seen in experiments.
POLYMER CRYSTALLIZATION IN SHEAR FLOW (theory)
Polymer crystallization is an old problem, but despite decades of study
relatively little is known theoretically about the transition into the
crystalline state. This is primarily because the nature of the transition
and the morphology of the final state are determined by kinetics and
topological constraints, rather than the well-understood principles
of equilibrium thermodynamics. Despite the paucity of knowledge,
semicrystalline polymers is a billion pound industry, and it is vitally
important, from both fundamental and applied points of view, to deepen
the understanding of polymer crystallization. The prospective student
will develop and solve models for the effect of flow on crystallization,
which affords a method to control the non-equilibrium and topological
constraints much better than simply cooling a quiescent melt. This will
be done within a large theory group devoted to the theory of polymer
melt dynamics, and in collaboration with experiments on model systems.