Dewetting kinetics of thin polymer bilayers: Role of under layer

Title
Dewetting kinetics of thin polymer bilayers: Role of under layer
Author(s)
아슈샬마린수Dipankar Bandyopadhy[Dipankar Bandyopadhy]Tongfei Shi[Tongfei Shi]Lijia An[Lijia An]주상우
Keywords
2-LAYERED LIQUID-FILM; NONLINEAR STABILITY ANALYSIS; SOFT ELASTOMERIC LAYERS; INTERFACE; INSTABILITY; SURFACTANT; DYNAMICS; MORPHOLOGY; THICKNESS; PATHWAYS
Issue Date
201109
Publisher
ELSEVIER SCI LTD
Citation
POLYMER, v.52, no.19, pp.4345 - 4354
Abstract
A combined experimental and computational study is presented to uncover the dewetting kinetics of the PS/PMMA system by changing the film thickness of the PMMA under layer. On the low M(w), PMMA (M(w) = 15 kg/mol) layer, the dewetting velocity of PS film firstly rapidly decreases (regime I), and then becomes almost invariant (regime II) with the increase of the film thickness of the liquid lower layer. Experiments suggest that the transition from regime I to regime II is correlative with the property of the solid substrates. The linear stability analysis of thin bilayers uncovers a bimodal behaviour of the instability under the experimental conditions and changeover of dominant mode of instability from one interface to the other is the major reason behind the switching of regimes. The nonlinear simulations closely mimic the experimental interfacial morphologies and suggest two different pathways of hole growth for regimes I and II under experimental condition. The simulations also indicate that the rapid reduction in the dewetting velocity is because of the increased excursion or penetration of the upper layer into the lower layer near the three phase contact line as the viscous resistance at the more viscous PMMA layer reduces with its increasing thickness. A qualitative match is thus found between the experimental and theoretical trends of the dewetting velocities. In addition, the experiments show that on a high M(w) PMMA (M(w) = 365 kg/mol) layer, the kinetics of hole growth of the PS layer is not affected by the PMMA layer thickness. (C) 2011 Elsevier Ltd. All rights reserved.
URI
http://hdl.handle.net/YU.REPOSITORY/24637http://dx.doi.org/10.1016/j.polymer.2011.06.060
ISSN
0032-3861
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공과대학 > 기계공학부 > Articles
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