The coil-globule transition of confined polymers

Abstract

We study long polymer chains in a poor solvent, confined to the space between two parallel hard walls. The walls are energetically neutral and pose only a geometric constraint which changes the properties of the coil-globule (or "$\theta$-") transition. We find that the $\theta$ temperature increases monotonically with the width $D$ between the walls, in contrast to recent claims in the literature. Put in a wider context, the problem can be seen as a dimensional cross over in a tricritical point of a ${\varphi }^4$ model. We roughly verify the main scaling properties expected for such a phenomenon, but we find also somewhat unexpected very long transients before the asymptotic scaling regions are reached. In particular, instead of the expected scaling $R\sim N^{4/7}$ exactly at the ($D$-dependent) theta point we found that $R$ increases less fast than $N^{1/2}$, even for extremely long chains.

arXiv comment5 pages, 6 figures

References in corpus (4)

• Fluctuation - induced forces in critical fluids
• Theta-point behavior of diluted polymer solutions: Can one observe the universal logarithmic corrections predicted by field theory?
• Effect of confinement on coil-globule transition
• Casimir Forces at Tricritical Points: Theory and Possible Experiments

Cited by in corpus (6)

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• Compressing $\Theta$-chain in slit geometry
• Scaling of loop-erased walks in 2 to 4 dimensions
• Hydrophobic homopolymer's coil-globule transition and adsorption onto a hydrophobic surface under different conditions
• Confined crowded polymers near attractive surfaces
• Randomly branching $\theta$-polymers in two and three dimensions: Average properties and distribution functions