Branched polymers in all shapes and sizes

Supervisor: Dr Daniel Read

Email: d.j.read@leeds.ac.uk

Phone: +44 (0)113 3435124

Office: 8.19j

Polymers (plastics) are very large molecules formed by joining lots of smaller ones together in a line - rather like molecular string. Sometimes these molecules contain branches, giving them a tree-like structure. The aim of the project is to try to deduce information about what sort of molecular shapes polymers can take. Sometimes the molecules are "self-similar" (or fractal) in nature, where each branch on the tree has the same average properties as all the others. In these cases we can use quite simple methods to tell us useful information about the polymer. There are a number of different properties of the molecule that are of interest, for example: their mass, the number of branches per molecule, their size. Harder to calculate, but of practical use, are "scattering" and "flow" properties. Depending on the interest and aptitude of the student, we shall look at some, or possibly all, of these.

The starting point for the project will be an introduction to these calculations in the case of linear (non-branched) polymers. The simplest branching structures will then be addressed. We might work towards calculations for polymers for a commercial reaction: "metallocene" polythene. No previous chemical knowledge will be assumed.

Books

Rubinstein, M.; Colby, R.H.: Polymer Physics Oxford Univ. Press, 2003

De Gennes, P.G.: Scaling Concepts in Polymer Physics (Cornell Univ. Press,1979) pgs 142-145

Flory, P.J: Principles of Polymer Chemistry Ithaca: Cornell University Press, 1953, Chapter IX

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Self-avoiding random walks on a lattice