Reducing Computational Complexity in Polymer Modeling

Mark P. Taylor, Hiram College, DMR 0804370

Computer modeling of polymer systems is important for both developing new materials and understanding how biological macromolecules function.

This type of modeling is made difficult by the large system sizes required to study a polymer molecule in a solvent. Through this research we seek to reduce the complexity of such simulations by mapping the chain-in-solvent system to a much simpler single-chain system with a set of interaction potentials that exactly reproduce the effects of solvent.

Using rigorous methods of liquid-state physics we compute exact solvation potentials for short chains [1,2]. We have developed techniques to extend these results to long chains which will allow us to study conformational transitions of macromolecules (such as proteins) [3,4] in a dense solvent environment.

[1] Taylor &Petersen*, Solvation potentials for flexible chain molecules in solution, J. Chem. Phys. 127, 184901 (2007).

[2] Taylor & Adhikari*, Conformation of a flexible chain in explicit solvent, J. Chem. Phys. 135, 044903 (2011).

[3] Taylor, Paul, & Binder, All-or-none protein-like folding of a flexible polymer chain, Phys. Rev E 79, 050801(R) (2009).

[4] Taylor, Paul, & Binder, Phase transitions of a single polymer chain, J. Chem. Phys. 131,114907 (2009).

* denotes Hiram undergraduate coauthor

In each case we are able to quantitatively map the many particle chain-in-solvent system to a much simpler single

chain system (with effective interactions).

In each case we are able to quantitatively map the many particle chain-in-solvent system to a much simpler single

chain system (with effective interactions).

Phase diagram for a Lennard-Jones (LJ) solvent andrepresentative conformations of a 20-bead LJ chain in

this solvent at liquid, vapor, and super-critical conditions.

Phase diagram for a Lennard-Jones (LJ) solvent andrepresentative conformations of a 20-bead LJ chain in

this solvent at liquid, vapor, and super-critical conditions.

liquid:ρ=0.8T=1.0

vapor: ρ=0.05T=1.0

super-critical:ρ=0.4, T=1.2

Reducing Computational Complexity in Polymer Modeling

Mark P. Taylor, Hiram College, DMR 0804370

One of the important goals of this NSF funded research program is to engage undergraduate students in a meaningful way in scientific research.

Our research students benefit from the the strong ties between their classroom learning and this research program and they see that science is a realistic professional option to be pursued.

Thus far, three students who worked on this project have graduated and all have gone on to pursue graduate study in physics (at Virginia Commonwealth, Case Western, and Kent State Universities).

At Hiram we emphasize that science is a community of scholars. Throughout the summer, our science faculty and student researchers exchange ideas and learn about each other's research at our weekly cookouts and journal club meetings.Student & faculty researchers at weekly summer picnics and journal club.Student & faculty researchers at weekly summer picnics and journal club.

Hiram students presenting on this project at the 2011 APS March Meeting, the Ohio Section APS 2011 Spring meeting, and the Fall 2010 Hiram College Research Symposium.

Hiram students presenting on this project at the 2011 APS March Meeting, the Ohio Section APS 2011 Spring meeting, and the Fall 2010 Hiram College Research Symposium.