Premium
Shape transitions in confined polymer mushrooms with excluded‐volume interaction
Author(s) -
Arteca Gustavo A.
Publication year - 1999
Publication title -
macromolecular theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 56
eISSN - 1521-3919
pISSN - 1022-1344
DOI - 10.1002/(sici)1521-3919(19990301)8:2<137::aid-mats137>3.0.co;2-h
Subject(s) - polymer , excluded volume , volume (thermodynamics) , work (physics) , chemical physics , lattice (music) , statistical physics , compression (physics) , molecular dynamics , materials science , thermodynamics , chemistry , physics , computational chemistry , composite material , acoustics
This work deals with some aspects of the molecular shape deformation of a single grafted polymer (a “polymer mushroom”) compressed by a repulsive wall. Compression not only changes the size of the polymer but also modifies its entanglements , i. e., how the chain's loops are folded onto themselves. These entanglements can be permanent (if based on a topological constraint) or transient (if related to a dynamical constraint). In the particular case of a single linear polymer, the term “self‐entanglement” refers to the essential geometrical characteristics of the transient loop interpenetrations. In this work, we discuss the interrelation between these two properties (i. e., molecular size and self‐entanglements) in off‐lattice polymers with variable excluded‐volume interaction. We show that, depending on the excluded volume, there can be a “shape transition”, that is, a significant change in the behaviour of molecular shape descriptors during compression. At low excluded volume, the molecular size is correlated with the chain entanglements when a compact polymer is compressed. In contrast, this correlation disappears if a swollen polymer mushroom is compressed. This transition can be described as a bifurcation when the complexity of self‐entanglements is expressed as a function of two variables: excluded volume and mean molecular size. We show that the simultaneous use of two distinct shape descriptors can provide insight into the structural stability of polymers.