Effect of rheology and interfacial tension on spreading of emulsion drops impacting a solid surface

Abstract

This paper presents an experimental and theoretical study of Newtonian and non-Newtonian (Bingham plastic) emulsion drop impact on a solid non-heated surface. The utilization of different emulsifiers at a constant concentration of continuous and dispersed phases in emulsions allows the considerable variation of the surface tension at the liquid–liquid interface. Our data for the maximum spreading diameter of water, n-decane, and emulsion drops impacting on a surface are compared with that predicted from the existing models for single-phase liquid drops. All selected models underpredict the experimental data. As a result, the importance of considering the capillary effects at the internal interfaces of the emulsion drops and the careful examination of all rheological properties in the case of Bingham plastic fluids is confirmed experimentally and is taken into account theoretically. The models of Pasandideh-Fard et al. [“Capillary effects during droplet impact on a solid surface,” Phys. Fluids 8, 650 (1996)] and Ukiwe and Kwok [“On the maximum spreading diameter of impacting droplets on well-prepared solid surfaces,” Langmuir 21, 666–673 (2005)] are modified and adapted to the emulsion drop by means of including the additional surface energy term at the liquid–liquid interface of the emulsion drop in the energy conservation equation and the non-Newtonian Reynolds number. The predictions of the maximum spreading diameter give good agreement with the measured one. Several constraints and future lines of research that relate to a specific behavior of the compound liquid drops at the impact on a solid surface are highlighted.

Hep3Gel: A Shape-Shifting Extracellular Matrix-Based, Three-Dimensional Liver Model Adaptable to Different Culture Systems

“…The spreading of drops deposited on a flat surface is a direct way to characterize the ability of a fluid to uniformly wet a surface, thus adapting to the shape of a specific container . However, this is an extremely tricky phenomenon to study since both the spreading dynamics and the equilibrium conformations depend on a multitude of parameters related to the nature of both the substrate and the drop material, and mathematical models describing these phenomena in general conditions usually lead to complex numerical solutions. − Since the described hydrogels have been specifically designed for tridimensional cell culture applications, this work is limited to the characterization of the self-spreading ability of the pregel solutions on polystyrene, which is the most common material to produce cell culture devices.…”

Physics of droplet impact on flexible materials: A review

“…The governing physical forces are interfacial tensions, gravity and viscosity. 17,55–57,124,148,204,211,221,250–276 Figure 6 illustrates the stationary condition of a droplet on a soft (flexible) substrate with interfacial tensions acting along the interfaces due to deformation of the soft substrate via impact of the droplet.…”

“…1–19 Physics of droplet-substrate interaction has been an attractive field of science in various technologies including healthcare, aerospace, electronics, coatings, printings and materials science. 20…”

“…This happens when the contact line advances on the substrate as a result of the competition between adhesion and cohesion forces at the three-phase contact line. 19,50–53,55,56,70–72,100,108,132,134–160 The adhesion force leads to the advancement the droplet on the substrate while the cohesion force resists the droplet advancement on the substrate.…”

Особенности Разрушения Микроструи Разбавленного Полимерного Раствора На Основные И Спутниковые Микрокапли Под Действием Внешнего Вибрационного Воздействия

“…Для многих этих технологий характерное для жидкостей с низкой вязкостью формирование спутниковых капель [7], т. е. значительно меньших по размеру фрагментов жидкости, образующихся между основными каплями разрушенной струи, является весьма нежелательным явлением и требует внимания с точки зрения управления. Особенно это явление актуально ввиду активного задействования сложных по внутренней структуре и компонентному составу жидкостей в производственных циклах и научно-исследовательских лабораториях, для которых, как показали эксперименты с каплями и струями [5,[7][8][9][10][11], существуют значительные отличия и характерные морфологические особенности в динамике жидкости по сравнению с однородными составами.…”