A Look Beyond Polymers

The interaction of lipids with small molecules was treated in a similar manner. Alcohols (butanols) were modeled simply as a dimer of a polar and an apolar site the polar site has the same interaction potential as does water, whereas the apolar site is the same as the alkanes in the lipids. This model makes the alcohol a symmetric amphiphile (which is not fully realistic). The alcohol concentrations had to be renormaHzed by Dickey et al. because one coarse-grained water represents four actual water molecules, whereas one coarse-grained butanol represents one real butanol. Accordingly, a concentration of 1 100 (butanohwater) in the coarse-grained model actually is 1 400 in the real system. 

This chapter focused on describing structural properties of polymers and related soft-matter systems using coarse-grained models. We need to point out two major caveats that are important and should be considered especially by novice modelers. 

Second, changing concentrations in polymer mixtures requires reevaluating the mapping. One must optimize all interaction potentials together at least in the final steps. 

The author thanks Alison Dickey and Qi Sun for assistance with the figures. Some of the work described here was financially supported by the U.S. Department of Energy, Office of Advanced Scientific Computing through an Early Career Grant (DE-FG02-03ER25568). 

Tschop, K. Kremer, J. Batoulis, T. Burger, and O. Hahn, Acta Polymerica, 49,61 (1998). 

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