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

Abstract

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.

arXiv comment5 pages, 4 figures

References in corpus (1)

• Long-Wavelength Instability in Surface-Tension-Driven Benard Convection

Cited by in corpus (6)

• Mechanism for Spontaneous Growth of Nanopillar Arrays in Ultrathin Films Subject to a Thermal Gradient
• Symmetry Plays a Key Role in the Erasing of Patterned Surface Features
• Oscillatory thermocapillary instability of a film heated by a thick substrate
• Differential Colorimetry Measurements of Fluctuation Growth in Nanofilms Exposed to Large Surface Thermal Gradients
• Self-Similar Cusp Formation in Thin Liquid Films By Runaway Thermocapillary Forces
• The effect of gravity on the stability of an evaporating dichloromethane liquid film