Ring-opening polymerization as a possible tool to prepare Olympic gels

Methods: Monte Carlo simulation, scaling, polymer dynamics.

Background: Olympic gels are networks made without cross-links. First simulation results [1] demonstrated unique swelling behaviour different to what was expected from theory. Beyond that, these materials are considered as an ideal model system to study the effect of entanglements between polymers, since there no perturbing effect of chemical cross-links on the material properties is possible [2]. To date, there was only one experimental group that proposed the formation of such Olympic gels [3] and results are not yet confirmed by other researchers. Also, this possible route of network formation was not considered theoretically yet [4], such that experimental data cannot be tested against theoretical predictions.

The task of this bachelor thesis is to close this gap. The bond fluctuation model will be applied to simulate ring opening polymerizations similar to the ones employed by Prof. Endo [3]. By consideration of the overlap of the molecules, relaxation and collision rates of ends, a resonable parameter range will be identified that might allow for the formation of interlocked molecular structures and enventually for the formation of Olympic gels. These interlocked states will be identified using knot theory. It will be checked whether concatenation affects the weight distribution of the polymerization in a characteristic manner to allow for an additional experimental analysis of concatenation. It further needs to be evaluated whether such a reaction can be forced into a parameter range that leads to the formation of an Olympic gel.

Supervisor: Prof. Dr. Jens-Uwe Sommer, Dr. Michael Lang


Prof. Dr. Jens-Uwe Sommer
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