Coil-bridge transition in a single polymer chain as an unconventional phase transition: Theory and simulation

Abstract

The coil-bridge transition in a self-avoiding lattice chain with one end fixed at height H above the attractive planar surface is investigated by theory and Monte Carlo simulation. We focus on the details of the first-order phase transition between the coil state at large height H ⩾ Htr and a bridge state at H ⩽ Htr, where Htr corresponds to the coil-bridge transition point. The equilibrium properties of the chain were calculated using the Monte Carlo pruned-enriched Rosenbluth method in the moderate adsorption regime at (H/Na)tr ⩽ 0.27 where N is the number of monomer units of linear size a. An analytical theory of the coil-bridge transition for lattice chains with excluded volume interactions is presented in this regime. The theory provides an excellent quantitative description of numerical results at all heights, 10 ⩽ H/a ⩽ 320 and all chain lengths 40 < N < 2560 without free fitting parameters. A simple theory taking into account the effect of finite extensibility of the lattice chain in the strong adsorption regime at (H/Na)tr ⩾ 0.5 is presented. We discuss some unconventional properties of the coil-bridge transition: the absence of phase coexistence, two micro-phases involved in the bridge state, and abnormal behavior in the microcanonical ensemble.

Coil-to-Bridge Transitions of Self-Assembled Water Chains Observed in a Nanoscopic Meniscus

“…The onset distance is even shorter with 2.8 nm, roughly 70% of that taken with the hydrophilic probe. The coil-to-bridge transition is driven by chain adsorption, theoretically predicted by earlier adsorption studies of a single polymer chain, tethered to an AFM probe on a surface . The adsorption energy is decreased by a factor of two since the hydrophobic probe can be considered to be inert.…”

“…The coil-to-bridge transition is driven by chain adsorption, theoretically predicted by earlier adsorption studies of a single polymer chain, tethered to an AFM probe on a surface. 43 The adsorption energy is decreased by a factor of two since the hydrophobic probe can be considered to be inert. The onset distance is predicted to depend on the square root of the adsorption energy (see the Supporting Information ), which leads to , thus explaining why we observe 70% of that taken between two hydrophilic surfaces.…”

Statistical mechanics of polymers subject to a force

“…This transition is referred to as the coil-bridge transition. This transition has been studied by Monte Carlo methods [86].…”