The Soft-Confined Method for Creating Molecular Models of Amorphous Polymer Surfaces

Hongyi Liu, Yan Li, Wendy E. Krause, Orlando J. Rojas*, Melissa A. Pasquinelli

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

23 Citations (Scopus)

Abstract

The goal of this work was to use molecular dynamics (MD) simulations to build amorphous surface layers of polypropylene (PP) and cellulose and to inspect their physical and interfacial properties. A new method to produce molecular models for these surfaces was developed, which involved the use of a "soft" confining layer comprised of a xenon crystal. This method compacts the polymers into a density distribution and a degree of molecular surface roughness that corresponds well to experimental values. In addition, calculated properties such as density, cohesive energy density, coefficient of thermal expansion, and the surface energy agree with experimental values and thus validate the use of soft confining layers. The method can be applied to polymers with a linear backbone such as PP as well as those whose backbones contain rings, such as cellulose. The developed PP and cellulose surfaces were characterized by their interactions with water. It was found that a water nanodroplet spreads on the amorphous cellulose surfaces, but there was no significant change in the dimension of the droplet on the PP surface; the resulting MD water contact angles on PP and amorphous cellulose surfaces were determined to be 106 and 33 degrees, respectively.

Original languageEnglish
Pages (from-to)1570-1578
Number of pages9
JournalJournal of Physical Chemistry B
Volume116
Issue number5
DOIs
Publication statusPublished - 9 Feb 2012
MoE publication typeA1 Journal article-refereed

Keywords

  • GLASS-TRANSITION TEMPERATURE
  • INVERSE GAS-CHROMATOGRAPHY
  • THIN-FILMS
  • DYNAMICS SIMULATIONS
  • COMPUTER-SIMULATION
  • TRIBLOCK COPOLYMER
  • CONTACT ANGLES
  • POLAR LIQUIDS
  • CELLULOSE
  • POLYPROPYLENE

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