Daniel Read's homepage

Hello, and welcome!

I am a Reader working in the Department of Applied Mathematics, where I am part of the Polymers and Non-Newtonian Fluid Mechanics group. My main research interests are in the fields of theoretical polymer physics and rheology. You can find some outline descriptions of the specific research topics I'm working on (or have worked on in the past) below. If you want to know more, then my publication list is here.

I am a joint administrator for the DYNACOP Marie Curie Initial training network. (DYNamics of Architecturally COmplex Polymers) - a joint venture with 9 other Universities and two companies across Europe.

I am a member of the Polymer IRC, which involves several departments across the University. I did my PhD and postdoc work in the Department of Physics, and maintain several collaborations with people over there.

PhD projects are available in all the areas below. Please get in touch if you are interested.

Polymer dynamics and rheology

Polymers are long molecules made from joining together lots of small molecules (or monomers). Sometimes polymer molecules are linear, but very often - notably in the case of Low Density Polyethylene (LDPE) used to make plastic bottles - they include many branches.

During the manufacture of polymeric (or plastic) materials and commodities, liquids containing polymers are subjected to flow. The way these liquids react is determined by the shapes, or configurations that the molecules adopt. Polymer molecules behave like springs, and become stretched by the flow, giving rise to the strongly elastic behaviour of polymeric fluids. The study of the dynamics of polymer molecules is very important for the understanding of flow of polymeric fluids.

If polymer molecules overlap sufficiently, then they get tangled up (like spaghetti) so that they are constrained in their movement. The "tube model" for entangled polymers provides a conceptual framework for understanding the constrained motion, and for making mathematical predictions about the polymers' response to flow.

Branchpoints in the polymer molecules provide addtional obstacles to the motion of entangled polymers, so that the distribution of branchpoints in polymer molecules can be a critical factor in determining flow properties.

I run a masters-level course (jointly with Dr Oliver Harlen) on Polymeric Fluids where some of these issues are explored.

Reaction chemistry and branched polymer architecture

There are different chemical routes used to produce branched polymers in an industrial setting. The particular reaction chemistry, and the reactor type and conditions, have a large effect on the number and distribution of branches throughout the polymer molecules.

As an example of this, metallocene catalysts form branches via the formation of "macromomonomers" (chains with double-bonds at the end) and the incorporation of these into growing chains (see left). Based on this simple mechanism, it is possible to derive mathematically the distributions of molecular size and branching.

One can extend these ideas to treat situations where there are several types of metallocene catalysts, or different reactor conditions, or different reaction chemistry (e.g. LDPE is usually manufactured via a free-radical chemistry which gives branching via an entirely different mechanism). The goal is an understanding of how chemistry affects branching, and how this in turn affects the flow properties of polymers.

Polymer dynamics and neutron scattering

It is important to understand the shapes, or conformations that polymers take under flow conditions. Although polymer rheology (the stress response of the fluid) is one way of probing this, it is important to have other independent tools to check that the theory is right. A more direct measure of polymer shape is obtained via neutron scattering.

Polymer molecules can be wholly, or partially "labelled" by replacing hydrogen atoms in the molecules with deuterium. Neutrons interact with deutrium differently to hydrogen, so that a beam of neutrons passing through a labelled melt of polymers will be scattered. The intensity, and angle, of scattering is related to polymer shapes.

The above picture shows neutron scattering patterns from a melt of H-shaped branched polymers, in which the middle of the polymers are deuterium-labelled. The melt was stretched, and scattering patterns taken at various times following the stretch (experimental results along top row). Theoretical calculations (bottom row) of the scattering pattern must account not only for the polymer shapes, but also the correlations between polymer molecules due to their interactions with one another.

Contact details

Publication list