Coil-globule transition: comparison of field theoretic and conformational space formulations

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Abstract
The description of polymer collapse is presented both in conformational space and field theoretic forms along the same lines as we have provided for treating the theta point (tricritical) region for polymers. This enables the problem to be considered in terms of the same measurable parameters which are used in the theta and good solvent regimes, thereby removing a serious deficiency of some previous treatments where the basic parameters of the theory are not directly measurable. The authors consider the self-consistency and range of validity of various mean field approaches and demonstrate the need for reinterpretation of some previous works. They generalise prior descriptions of the coil-globule transition to include contributions from fluctuations and to determine the excitations of the globule. In addition, criteria are derived giving the limits of stability of the globular phase. The analysis underlies the profound role played by the effective three-body interaction upon the nature of the transition, explaining the source of previously suggested 'non-universality' of this transition.