کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
590839 1453565 2013 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Dynamic wetting of dilute polymer solutions: The case of impacting droplets
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Dynamic wetting of dilute polymer solutions: The case of impacting droplets
چکیده انگلیسی


• This paper reviews the literature about the impact of dilute polymer solution drops on hydrophobic surfaces.
• Early approaches are analyzed critically to highlight their flaws.
• Recent results demonstrating the true physical mechanism of the phenomenon are discussed.

The moving contact line of a dilute polymer solution that advances over, or recedes from a solid substrate, is a fundamental problem of fluid dynamics with important practical applications. In particular, the case of droplets impacting on hydrophobic surfaces received much attention in the recent past. Experiments show that while the advancing motion proceeds as with Newtonian liquids, recession is severely inhibited. This phenomenon was initially understood as an effect of elongational viscosity, which was believed to cause large energy dissipation in the fluid. Later on, a hydrodynamic mechanism was proposed to suggest that the slowing down of the contact line is due to non-Newtonian normal stresses generated near the moving droplet edge. Recent experiments however ruled out the role of elongational viscosity, showing that the fluid velocity measured inside the droplet during retraction is the same in water drops and polymer solution drops. Direct visualization of fluorescently stained λ-DNA molecules showed that polymer molecules are stretched perpendicularly to the contact line as the drop edge sweeps the substrate, which suggests an effective friction arises locally at the drop edge, causing the contact line to slow down.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Advances in Colloid and Interface Science - Volumes 193–194, June 2013, Pages 1–11
نویسندگان
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