Speaker
Description
Spontaneous nanoparticle adsorption from suspension has emerged as a promising approach for tuning wettability, particularly in natural systems where direct manipulation of surface textures is challenging. However, whether and how such spontaneous adsorption on solid surfaces enables robust modification of wettability remains debated. Here, we report a series of studies on nanoparticle-induced wettability alteration across scales through microscopic characterizations, microfluidic experiments, and modeling.
At the interfacial scale, we present a comprehensive description of particle size effects on changing wettability under varying electrolyte concentrations and surface charge conditions, revealing a nonmonotonic dependence of apparent wettability on particle size in the presence of particle–wall and interparticle repulsive barriers. Through coupling macroscopic geometric effects of adsorbed particles on apparent wettability and microscopic adsorption–desorption kinetics, our modeling results fit well with experimental observations. We construct a phase diagram that incorporates two key factors governing the competition between adsorption and desorption kinetics, and formulate a comprehensive dimensionless number to quantitatively predict the optimal conditions for wettability alteration.
Motivated by striking contrasts in static wettability under different phase configurations, we further identify the criterion for nanoparticle-induced wettability alteration during displacement. We find that nanoparticle adsorption affects displacement interfaces only when spreading of wetting films is pre-established, corresponding to corner-flow conditions. Microfluidic displacement experiments under varying intrinsic wettability show that film development and nonaqueous droplet detachment are strengthened exclusively on moderately water-wet surfaces satisfying the corner-flow criterion. Investigations across designed porous structures with varying degrees of structural hierarchy validate the generality of the wettability criterion, while improvement in displacement efficiency diminishes with reduced hierarchy. The coupled impacts of intrinsic wettability and structural conditions are summarized in an illustrative phase diagram delineating nanoparticle-tuned multiphase displacement.
These findings offer optimized treatment strategies for surface property modification and multiphase flow control by nanoparticle suspensions, applicable to broad scenarios including geological and living systems.
| Country | China |
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| Student Awards | I would like to submit this presentation into the Earth Energy Science (EES) and Capillarity Student Poster Awards. |
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