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Molecular arrangements and conformations of chain molecules near impenetrable surfaces
Author(s) -
Vacatello Michele,
Yoon Do Y.
Publication year - 1991
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19910480125
Subject(s) - chain (unit) , surface (topology) , monte carlo method , molecule , gaussian , ideal (ethics) , molecular physics , chemical physics , physics , geometry , chemistry , crystallography , materials science , computational chemistry , mathematics , quantum mechanics , philosophy , statistics , epistemology
The Monte Carlo method has been used to model liquids of chain molecules confined between two impenetrable surfaces (walls). Two kinds of chains have been simulated in two separate calculations: short n‐alkane (n‐tridecane) chains represented at the atomic level in the first case and long polymer chains represented as necklaces of beads in the second case. Molecules located far from the walls are in remarkable agreement with ideal unperturbed chains in both calculations. The shapes and orientations of chain segments located near the walls are substancially different from those in the bulk. Starting from the walls, n‐tridecane exhibit progressively less dense and less ordered segmental layers of ca. 0.4 nm thickness, with most of the units in the first segmental layer belonging to nearly two‐dimensional chains. Long chains with center of mass close to the walls assume open, practically two‐dimensional conformations comprised mainly of surface trains and loops. The interface corresponds then to a region where the conformations of the chains evolve from these nearly two‐dimensional structures near the walls to the unperturbed, three‐dimensional Gaussian conformations in the bulk.