Cellulosic polymers have wide applications in various fields (e.g. pharmaceutical, agriculture, food) due to the polyfunctionality achieved via the three substitution positions on each monomer unit. In this study, we adopt atomistic molecular dynamics (MD) simulation technique to model the solvation behavior of homogenous cellulosic polymer chains (e.g. cellulose, methylcellulose, and hydroxypropyl methylcellulose) and model oligomer chains that represent the commercial cellulosic polymer product � METHOCEL� in both water and organic solvent. The atomistic resolution of these simulations offers insights of specific polymer-polymer interactions of these polymers, and can be used as a cost-effective screening tool for predicting the solvation behavior of novel cellulosic polymer compositions. Both single chain simulations and multiple chains simulations are performed using GROMACS simulation package. The single chain simulations are conducted using both GROMOS and CHARMM force fields and the order of hydrophobicity is found to be independent of the choice of force field. These carbohydrate force fields are also capable of reproducing theoretical rod-like regime polymer properties. Multiple chains simulations are carried using GROMOS force field and it is shown that the substitution position on the cellulosic chains has direct effect on the solvation behavior. In addition, drastically different solvation behaviors have been observed for these multiple chains systems in different solvents. We have modeled two different METHOCEL� products with model oligomers and have demonstrated that the solvation behaviors in small scale model systems correlate well with those in real experimental systems. However, the scale of these simulations is too limited to model any macroscopic polymer solvation behavior, such as gelation.

Study of cellulosic polymer solvation behavior by atomistic molecular dynamics simulations

247th National Meeting (2014)

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