Publication Type
Journal
Journal Name
Macromolecules
Publication Date
Page Numbers
4207 to 4219
Volume
48
Issue
12
Abstract
We present a detailed analysis of coarse-grained molecular dynamics simulations of semiflexible
polymer melts in contact with a strongly adsorbing substrate. We have characterized
the segments in the interfacial layer by counting the number of trains, loops, tails and unadsorbed
segments. For more rigid chains, a tail and an adsorbed segment (a train) dominate
while loops are more prevalent in more flexible chains. The tails exhibit a non-uniformly
stretched conformation akin to the “polydispersed pseudobrush” envisioned by Guiselin. To
probe the dynamics of the segments we computed the layer z-resolved intermediate coherent
collective dynamics structure factor, S(q; t; z), mean-square displacement of segments, and the
2nd Legendre polynomial of the time-autocorrelation of unit bond vectors, hP2[~ni(t; z) ~ni(0; z)]i.
Our results show that segmental dynamics is slower for stiffer chains and there is a strong correlation
between the structure and dynamics in the interfacial layer. There is no “glassy layer”,
and the slowing down in dynamics of stiffer chains in the adsorbed region can be attributed to
the densification and the more persistent layering of segments.
