کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
610088 880639 2009 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
On the pinning of interfaces on micropillar edges
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
On the pinning of interfaces on micropillar edges
چکیده انگلیسی

Microsystems for biotechnology often make use of pillars to perform the targeted microfluidic functions. In many cases the role of the pillars is to block or maintain fixed an interface between two immiscible fluids. This phenomenon is usually called pinning. The pining principle is used for capillary valves, liquid–liquid extraction devices, etc. It is common to estimate the pinning efficiency by considering mathematically perfect edges. In reality, microfabricated edges always show some smoothness that can be modeled by a small curvature radius. In this work, we investigate the pinning on square, circular, triangular, and diamond-shaped pillars, and analyze the anchoring on the upstream edges (first pinning conditions) and possibly on the downstream edges (second pinning conditions). It is shown that pinning efficiency decreases very quickly with the curvature radius of the pillar edge. It is concluded that the quality of the microfabrication is essential. Especially oxidation of the silicon reduces considerably the pinning efficiency. Moreover, it is shown that square pillars pin better an interface than triangular pillars. For triangular pillars, a pillar angle—angle between two facets—optimal for pinning has been determined that depends on the quality of microfabrication.

Modeling of the pinning of an interface on rounded edged micropillars. The pinning is less effective and depends on the curvature radius of the edges.Figure optionsDownload high-quality image (53 K)Download as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Colloid and Interface Science - Volume 338, Issue 1, 1 October 2009, Pages 296–303
نویسندگان
, , , , , , ,