Lattice Monte Carlo simulation of polymer adsorption at an interface, 1 - Monodisperse polymer

摘要

Adsorption of a monodisperse polymer at a solid-liquid interface is comprehensively studied by Monte Carlo simulation. The distributions of total segment density and different adsorption configurations including trains, loops and tails are obtained. Effects of seduced exchange interaction energies <(epsilon)over tilde>, bulk concentrations phi*, reduced adsorption energies <(epsilon)over tilde>(a) and chain lengths r on those distributions are studied. Comparisons with predictions of the Scheutjens-Fleer (SF) theory are also provided. Generally, the chain molecules are more easily adsorbed at an interface in non-solvents than in good solvents. Longer chains are more likely to be adsorbed than shorter ones. The reduced adsorption energy and the bulk concentration have shown strong effects on the segment-density distributions. In addition, the thickness of the adsorption layer is mainly determined by the extension of tails into the bulk solution, which are in turn determined by the chain length. The trains, loops and tails are overwhelmingly short. On the other hand, the amounts of trains and loops are usually much greater than that of tails. Though not perfect, satisfactory agreement is found in comparison with the theoretical predictions of the SF theory. [References: 36]