Creating self-organized submicrometer contact instability patterns in soft elastic bilayers with a topographically patterned stamp

Mukherjee, Rabibrata ; Sharma, Ashutosh (2012) Creating self-organized submicrometer contact instability patterns in soft elastic bilayers with a topographically patterned stamp ACS Applied Materials & Interfaces, 4 (1). pp. 355-362. ISSN 1944-8244

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Official URL: http://pubs.acs.org/doi/abs/10.1021/am201422h

Related URL: http://dx.doi.org/10.1021/am201422h

Abstract

The surface of a thin elastic bilayer becomes spontaneously unstable when it is brought in proximity to another rigid contactor. The instability patterns, which are random and isotropic, exhibit a dominant lateral length scale of instability λ, which linearly scales with the bilayer thickness (h) as: λ = RFh. It is known that for an elastic bilayer, RF exhibits a nonlinear dependence on the ratios of individual film thicknesses (H) and shear moduli (M) of the two constituent layers, and can have values as low as 0.5 under specific conditions. This is in contrast to a near constant value of RF ≈ 3 for a single layer elastic film.(1) These isotropic contact instability patterns in a bilayer can be ordered, aligned and modulated using a topographically patterned stamp. The precise morphology of the aligned structures depends on commensuration between λ and the stamp periodicity (λP), and on the intersurface separation distance. A variety of patterns, like an array of circular holes, double periodic channels, etc., in addition to a positive and a negative replica of the stamp pattern, can be engineered with a simple stamp having 1D grating structure. A lower value of RF in a bilayer allows generating patterns with sub 500 nm lateral resolution, which is impossible to create by elastic contact lithography (ECL) of a single layer film due to strong surface tension effects in ultrathin films. Thus, control of elastic instability in a bilayer with a patterned stamp represents a flexible soft lithography tool allowing modulation of length scales, morphology, and order.

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
Keywords:Self Organization; Bilayer; Patterns; Elastic Film,;Soft Lithography; Thin Film Instability
ID Code:96551
Deposited On:02 Jan 2013 08:54
Last Modified:02 Jan 2013 08:56

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