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When tethered chains meet free ones; the stability of polymer wetting films on polymer brushes
Author(s) -
Maas Joost H.,
Leermakers Frans A.M.,
Fleer Gerard J.,
Stuart Martinus A. Cohen
Publication year - 2003
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200390015
Subject(s) - wetting , polystyrene , disjoining pressure , materials science , degree of polymerization , polymer , polymer chemistry , contact angle , polymerization , metastability , grafting , polymer brush , chemical physics , thermodynamics , composite material , chemistry , organic chemistry , physics
We present a combined experimental and theoretical self‐consistent field (SCF) investigation of the wetting behavior of a polystyrene melt (composed of chains with degree of polymerization P ) on top of a polystyrene brush (composed of chains with length N ) grafted onto a silica surface. The control variables are the grafting density σ of the brush chains and the length of mobile chains P . Experiments show in agreement with the theory that there is a window of complete wetting. Both at very low and at high grafting densities the system remains partial wet. At large degree of polymerization P , there is a difference between the experimental and theoretical results. Theory predicts partial wetting only, whereas the window of complete wetting persists in the experiments even when P >> N . This difference is attributed to the double‐well structure of the disjoining pressure as revealed by the SCF theory. With this type of disjoining pressure it is conceivable that a metastable zero contact angle remains present for very long times.