A Monte Carlo investigation of the statistical thermodynamics for polymers in various solvent types : simulations of the free chain, the grafted chain, and two chains grafted to a common wall

Author

Charlene Carpenter Sorensen

Date of Award

12-1998

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Chemistry

Major Professor

Jeffrey D. Kovac

Abstract

This study is a Monte Carlo computer simulation of three systems: a free polymer chain in various solution types, a grafted polymer with one end of the chain tethered to a wall of varying attractiveness in various solution types, and two grafted chains connected to a common non-attractive wall in various solution types. The focus of the study was to evaluate the chain dynamics for the various Rouse modes for each of the simulation types mentioned above. The results of each simulation were used to make generalizations about the dynamics of the polymer chains and to assess the differences resulting from the parameters used for each simulation type. The results for the single free chain answered the question of the origin of the slow relaxation for the higher normal modes. The simulation showed that the life-time and number of bead-bead contacts were indeed affecting the relaxation times of the higher modes. For the grafted chain, the effect of an interactive wall as well as the effect of grafting a chain to the wall were evaluated. These values showed the conformation and relaxations depend strongly on the attractiveness of both the polymer chains and the wall. There is also a suggestion that when the wall is highly attractive, the polymer fits within the parameters of a two dimensional model. For the two interacting chains, the evaluation of static and dynamic information was done with respect to the distance between chains. The decreasing distance between chains gave insight into issues involving entanglement and its inhibiting affect on the movement toward a relaxed, low energy conformation for the polymers. In short, bead-bead contacts play a major role in a variety of polymer systems. These contacts affect both the static and dynamic properties. The impact of such contacts is even more evident when analysis is done for the higher modes.

Recommended Citation

Sorensen, Charlene Carpenter, "A Monte Carlo investigation of the statistical thermodynamics for polymers in various solvent types : simulations of the free chain, the grafted chain, and two chains grafted to a common wall. " PhD diss., University of Tennessee, 1998.
https://trace.tennessee.edu/utk_graddiss/9367