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The gel‐like structure of polymer in thin films: an explanation of the thickness dependent glass transition?
Author(s) -
Grohens Yves,
Hamon Loic,
Spěváček Jiří,
Holl Yves
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.200351314
Subject(s) - polymer , glass transition , materials science , thin film , evaporation , solvent , spin coating , chemical physics , adsorption , chemical engineering , chain (unit) , polymer chemistry , composite material , crystallography , chemistry , thermodynamics , nanotechnology , organic chemistry , physics , astronomy , engineering
Abstract The understanding of the origin of the thickness ( h ) dependent glass transition temperature, T g ( h ), reported over the last decade for supported and freely standing thin polymer films, is still unclear. Indeed, the spin‐coating process, the interfacial adsorption as well as the freezing‐in of non‐equilibrated chain conformations and orientations caused by fast solvent evaporation could result in partially disentangled chains which can be depicted as a gel‐like structure. The effect of PMMA stereoregularity on the chain conformation and orientation and its persistence length in thin films is discussed. Moreover, striking evolutions of T g ( h ) by changing the nature of the solvent support the assumption of a specific organisation of the chains in thin films which can hold over thickness far above R g.