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 .
PHYSICS OF MECHANICAL UNFOLDING OF PROTEINS AND NUCLEIC ACIDS
Atomic Force Microscopy has emerged as a valuable tool for measuring the
mechanical response of single molecules. Single molecules can be pulled
and led through different structural transitions (unfolding, denaturation
of DNA and RNA, etc), whose characteristics can be inferred from analysis
of the mechanical response. There are several possible projects in this
area that involve collaboration with experiments on mechanical unfolding,
using a range of theoretical techniques and/or simulation, depending on
the backgrounds and interests of the student.
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.
PHASE BEHAVIOUR AND DYNAMICS OF BIOMEMBRANES (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.
Possible projects include the dynamics and mechanics of proteins in
membranes, the dynamics of phase separation in membranes, the role of
membrane composition in protein function, and the mechanism by which
general anaesthetics work. There are possibilities for collaborations
with experimentalists and theorists at Leeds and elsewhere.
FLOW-INDUCED PHASE TRANSITIONS IN COMPLEX FLUIDS (theory)
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).
The student will study models of increasing complexity for the dynamics
of complex fluids, with a goal of trying to understand different aspects
of time-dependent oscillatory or chaotic states seen in experiments.
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.
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.