Folding mechanism of a polymer chain with short-range attractions

Author(s)
Christian Leitold, Christoph Dellago
Abstract

We investigate the crystallization of a single, flexible homopolymer chain using transition path sampling. The chain consists of N identical spherical monomers evolved according to Langevin dynamics. While neighboring monomers are coupled via harmonic springs, the non-neighboring monomers interact via a hard core and a short-ranged attractive potential. For a sufficiently small interaction range λ, the system undergoes a first-order freezing transition from an expanded, disordered phase to a compact crystalline state. Using a new shooting move tailored to polymers combined with a committor analysis, we study the transition state ensemble of an N = 128 chain and search for possible reaction coordinates based on likelihood maximization. We find that typical transition states consist of a crystalline nucleus with one or more chain fragments attached to it. Furthermore, we show that the number of particles in the crystalline core is not well suited as a reaction coordinate. We then present an improved reaction coordinate, which includes information from the potential energy and the overall crystallinity of the polymer

Organisation(s)
Computational and Soft Matter Physics
Journal
Journal of Chemical Physics
Volume
141
No. of pages
11
ISSN
0021-9606
DOI
https://doi.org/10.1063/1.4896560
Publication date
10-2014
Peer reviewed
Yes
Austrian Fields of Science 2012
103023 Polymer physics, 103029 Statistical physics, 103036 Theoretical physics
ASJC Scopus subject areas
General Physics and Astronomy, Physical and Theoretical Chemistry
Portal url
https://ucrisportal.univie.ac.at/en/publications/9379847c-f2bc-4ba7-8313-add7a6da0ff1