Inverse swelling of a hydrophobic polymer in aqueous solution

Marco Pretti

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Inverse swelling of a hydrophobic polymer in aqueous solution

Marco Pretti

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Abstract

We address the problem of inverse polymer swelling. This phenomenon, in which a collapsed polymer chain swells upon decreasing temperature, can be observed experimentally in so-called thermoreversible homopolymers in aqueous solution, and is believed to be related to the role of hydrophobicity in protein folding. We consider a lattice-fluid model of water, defined on a body-centered cubic lattice, which has been previously shown to account for most thermodynamic anomalies of water and of hydrophobic solvation for monomeric solutes. We represent the polymer as a self-avoiding walk on the same lattice, and investigate the resulting model at a first order approximation level, equivalent to the exact calculation on a Husimi lattice. Depending on interaction parameters and applied pressure, the model exhibits first and/or second order swelling transitions upon decreasing temperature.

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Marco Pretti. 2006-05-29. Inverse swelling of a hydrophobic polymer in aqueous solution. https://arxiv.org/abs/cond-mat/0605707

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