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Published August 14, 2009 | public
Journal Article

Formation of Nanopillar Arrays in Ultrathin Viscous Films: The Critical Role of Thermocapillary Stresses


Experiments by several groups during the past decade have shown that a molten polymer nanofilm subject to a large transverse thermal gradient undergoes spontaneous formation of periodic nanopillar arrays. The prevailing explanation is that coherent reflections of acoustic phonons within the film cause a periodic modulation of the radiation pressure which enhances pillar growth. By exploring a deformational instability of particular relevance to nanofilms, we demonstrate that thermocapillary forces play a crucial role in the formation process. Analytic and numerical predictions show good agreement with the pillar spacings obtained in experiment. Simulations of the interface equation further determine the rate of pillar growth of importance to technological applications.

Additional Information

©2009 The American Physical Society. Received 19 March 2009; published 13 August 2009. We gratefully acknowledge support from the NSF-ECCS Division and early discussions with Dr. A. Darhuber at Princeton University. # 47.85.md Polymer processing flows # 47.20.Dr Surface-tension-driven flow instability # 47.61.-k Micro- and nano-scale flow phenomena # 63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials

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August 21, 2023
October 19, 2023