Self-assembled nanoparticle-coated interfaces: Capillary pressure, shell formation and buckling

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:581

Article

Liu, Q.¹  Sun, Z.²  Santamarina, J. Carlos¹ 

[1] King Abdullah Univ Sci & Technol KAUST, Earth Sci & Engn, Thuwal 239556900, Saudi Arabia

[2] Univ Texas Austin, Hildebrand Dept Petr & Geosyst Engn, Austin, TX 78712 USA

关键词: Particle-coated interface;    Buckling patterns;    Multi-phase flow;    Capillarity;    Oil displacement;   

DOI  :  10.1016/j.jcis.2020.07.110

来源: Elsevier

【 摘 要 】

Hypothesis: Particle accumulation at liquid-liquid or liquid-gas interfaces can significantly alter capillary behavior and give rise to unusual interfacial phenomena including the asymmetric macroscopic mechanical response of the interface. Experiments: This study explores the accumulation of cetyltrimethylammonium bromide-modified nanoparticles at fluid interfaces and the subsequent mechanical response of nanoparticle-coated droplets during contraction and expansion. Droplet tests involve the simultaneous recording of the droplet shape and the capillary pressure. Complementary single-pore experiments examine the response of particle-coated interfaces as they traverse a pore constriction. Findings: Interfaces promote order. The time-dependent nanoparticle accumulation at the interface is diffusion-controlled. The nanoparticle coated droplets can sustain negative capillary pressure before they buckle. Buckling patterns strongly depend on the boundary conditions: non-slip boundary conditions lead to crumples while slip boundary conditions result in just a few depressions. The particle-coated interface exhibits asymmetric behavior in response to particle-level capillary forces: an oil droplet in a nanofluid bath withstands a significantly higher capillary pressure difference than a nanofluid droplet in an oil bath. A first-order equilibrium analysis of interaction forces explains the asymmetric response. Single-constriction experiments show that the formation of particle-coated interfaces has a pronounced effect on fluid displacement in porous media. (C) 2020 The Author(s). Published by Elsevier Inc.

【 授权许可】

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