Authors Vix, A.B.E. ; Müller-Buschbaum, P. ; Stocker, W. ; Stamm, M.
Title Crossover between Dewetting and Stabilization of Ultrathin Liquid Crystalline Polymer Films
Date 21.12.2000
Number 9655
Abstract Thin spin-coated films of a smectic liquid crystalline main chain polymer with an azoxybenzene asmesogen were investigated as a function of temperature and thickness. Both lateral and vertical order ofthe polymer film in the various mesophases were determined by scanning force microscopy in tapping modeand by specular and off-specular X-ray scattering. For films thicker than 10 nm, we observed a stabilizingeffect of the smectic organization within the film. No dewetting was detected. The bulk structure of thefilm consists of smectic layers with a thickness of 3.5 nm, oriented parallel to the substrate. The excessmaterial formed smectic islands on top of the film, corresponding to a noncomplete smectic layer. For filmsthinner than 10 nm, corresponding to one or two smectic layers only, we observed dewetting with theformation of holes. The holes were dry without any remaining monolayer on the substrate. However, thewithdrawing polymer did not accumulate in rounded rims such as for amorphous polymers but in smectictowers, due to the packing of the polymer chain.
Publisher Langmuir
Citation Langmuir 16 (2000) 10456-10462
Tags diblock copolymer films main-chain polymers thin-films free-surface reflectivity slippage mobility growth phase order

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