Forced-induced desorption of a polymer chain adsorbed on an attractive surface - Theory and Computer Experiment

Abstract

We consider the properties of a self-avoiding polymer chain, adsorbed on a solid attractive substrate which is attached with one end to a pulling force. The conformational properties of such chain and its phase behavior are treated within a Grand Canonical Ensemble (GCE) approach. We derive theoretical expressions for the mean size of loops, trains, and tails of an adsorbed chain under pulling as well as values for the universal exponents which describe their probability distribution functions. A central result of the theoretical analysis is the derivation of an expression for the crossover exponent $\varphi$, characterizing polymer adsorption at criticality, $\varphi =\alpha -1$, which relates the precise value of $\varphi$ to the exponent $\alpha$, describing polymer loop statistics. We demonstrate that $1-{\gamma }_{11}<\alpha <1+\nu$, depending on the possibility of a single loop to interact with neighboring loops in the adsorbed polymer. The universal surface loop exponent ${\gamma }_{11}\approx -0.39$ and the Flory exponent $\nu \approx 0.59$. We present the adsorption-desorption phase diagram of a polymer chain under pulling and demonstrate that the relevant phase transformation becomes first order whereas in the absence of external force it is known to be a continuous one. The nature of this transformation turns to be dichotomic, i.e., coexistence of different phase states is not possible. These novel theoretical predictions are verified by means of extensive Monte Carlo simulations.

24 pages, 14 figures

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Cited by in corpus (8)

• Stretching Semiflexible Polymer Chains: Evidence for the Importance of Excluded Volume Effects from Monte Carlo Simulation
• Forcing Adsorption of a Tethered Polymer by Pulling
• Polymer Detachment Kinetics from Adsorbing Surface: Theory, Simulation and Similarity to Infiltration into Porous Medium
• Polymer desorption under pulling: a novel dichotomic phase transition
• Pulling an adsorbed polymer chain off a solid surface
• Adsorption of finite semiflexible polymers and their loop and tail distributions
• Transitions of tethered chain molecules under tension
• Dynamics of pulled desorption with effects of excluded volume interaction: The p-Laplacian diffusion equation and its exact solution