Regensburg 2010 – scientific programme
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DS: Fachverband Dünne Schichten
DS 46: Organic Thin Films III
DS 46.7: Talk
Friday, March 26, 2010, 15:30–15:45, H8
Coverage and Morphology Dependence of Dip Coated Organic Films on Withdrawal Velocity — •Tomás Corrales1,2, Pía Homm2, Piero Ferrari2, María J. Retamal2, Edgardo A. Cisternas3,2, Valeria del Campo4,2, and Ulrich G. Volkmann2 — 1Max-Planck-Institut für Polymerforschung, Mainz, Germany — 2Dept. of Physics, P. Universidad Católica de Chile, Santiago de Chile — 3Dept. of Research and Development, Tecnología Integral S.A., Santiago de Chile — 4Dept. of Hydraulic and Environmental Engineering, P. Universidad Católica de Chile, Santiago de Chile
In this work we dip-coat n-dotriacontane onto silicon substrates, coated with their native oxide film (≈15 Å), from an n-heptane solution varying systematically the withdrawal velocity from 0.04 cm/min to 9.25 cm/min. After coating, we study the resulting films with AFM and SEM. We observe the formation of self-assembled monolayer structures with different coverage and morphologies, depending on the withdrawal velocity: For a pulling velocity of 1 cm/min we observe a minimum coverage of ≈11% while a maximum coverage of ≈54% is reached for the slowest velocity (0.04 cm/min). For velocities higher than 5 cm/min we observe a stabilization at a coverage of ≈35%. We relate this behavior to the transition from a gravity driven film growth to an entrained film regime, proposed by M. Ghosh et al. [1]. We also find that the morphology of these structures depends strongly on the withdrawal velocity.
[1] M. Ghosh, F. Fan, K.J. Stebe, Langmuir 23 (4), 2007.
This work is supported by FONDECYT 1060628.