Unraveling driving regimes for destabilizing concentrated emulsions within microchannels

Author(s)

Porto Santos, Tatiana ^{[1, 2]} ; Cejas, Cesare M. ^[2] ; Cunha, Rosiane Lopes ^[1] ; Tabeling, Patrick ^[2]

Affiliation

^[1] Univ Estadual Campinas, Dept Food Engn, Fac Food Engn, Rua Monteiro Lobato, 80, BR-13083862 Campinas - Brazil

^[2] PSL Res Univ, Inst Pierre Gilles Gennes IPGG, Nanostruct Lab, ESPCI Paris, Microfluid, MEMS, CNRS, Chim Biol Innovat CBI UMR 82, 6 Rue Jean Calvin, F-75005 Paris - France

• Document type: Journal article
• Source: SOFT MATTER; v. 17, n. 7, p. 1821-1833, FEB 21 2021.
• Web of Science Citations: 0

Abstract

Coalescence is the most widely demonstrated mechanism for destabilizing emulsion droplets in microfluidic chambers. However, we find that depending on the channel wall surface functionalization, surface zeta potential, type of surfactant, characteristics of the oil as a dispersed phase, or even the presence of externally-induced stress, other different destabilization mechanisms can occur in subtle ways. In general, we observe four regimes leading to destabilization of concentrated emulsions: (i) coalescence, (ii) emulsion bursts, (iii) a combination of the two first mechanisms, attributed to the simultaneous occurrence of coalescence and emulsion bursts; and (iv) compaction of the droplet network that eventually destabilizes to fracture-like behavior. We correlate various physico-chemical properties (zeta potential, contact angle, interfacial tension) to understand their respective influence on the destabilization mechanisms. This work provides insights into possible ways to control or inflict emulsion droplet destabilization for different applications. (AU)

• FAPESP's process: 19/07744-1 - Use of microfluidic devices to evaluate emulsion stability
• Grantee: Rosiane Lopes da Cunha
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/18109-0 - Development of an emulsion stability analyzer from microfluidics
• Grantee: Tatiana Porto dos Santos
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/18103-4 - Systematic study of microchannels to evaluate coalescence in oil-in-water and water-in- oil emulsions
• Grantee: Tatiana Porto dos Santos
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate