title: Linking Findings in Microfluidics to Membrane Emulsification Process Design: The Importance of Wettability and Component Interactions with Interfaces.
abstract: In microfluidics and other microstructured devices, wettability changes, as a result of component interactions with the solid wall, can have dramatic effects. In emulsion separation and emulsification applications, the desired behavior can even be completely lost. Wettability changes also occur in one phase systems, but the effect is much more far-reaching when using two-phase systems. For microfluidic emulsification devices, this can be elegantly demonstrated and quantified for EDGE (Edge-base Droplet GEneration) devices that have a specific behavior that allows us to distinguish between surfactant and liquid interactions with the solid surface. Based on these findings, design rules can be defined for emulsification with any micro-structured emulsification device, such as direct and premix membrane emulsification. In general, it can be concluded that mostly surface interactions increase the contact angle toward 90°, either through the surfactant, or the oil that is used. This leads to poor process stability, and very limited pressure ranges at which small droplets can be made in microfluidic systems, and cross-flow membrane emulsification. In a limited number of cases, surface interactions can also lead to lower contact angles, thereby increasing the operational stability. This paper concludes with a guideline that can be used to come to the appropriate combination of membrane construction material (or any micro-structured device), surfactants and liquids, in combination with process conditions.
authors.affiliation: Food Process Engineering Group, Department of Agrotechnology &amp; Food Science, Wageningen University, Bornse Weilanden 9, Wageningen 6708 WG, The Netherlands. karin.schroen@wur.nl.
authors.forename: Karin
authors.initials: K
authors.lastname: Schroën
authors.affiliation: Departament d'Enginyeria Química, Escola Tècnica Superior d'Enginyeria Química, Universitat Rovira i Virgili, Avda. Països Catalans 26, Tarragona 43007, Spain. montse.ferrando@urv.cat.
authors.forename: Montse
authors.initials: M
authors.lastname: Ferrando
authors.affiliation: Departament d'Enginyeria Química, Escola Tècnica Superior d'Enginyeria Química, Universitat Rovira i Virgili, Avda. Països Catalans 26, Tarragona 43007, Spain. silvia.delamo@urv.cat.
authors.forename: Silvia
authors.initials: S
authors.lastname: de Lamo-Castellví
authors.affiliation: Food Process Engineering Group, Department of Agrotechnology &amp; Food Science, Wageningen University, Bornse Weilanden 9, Wageningen 6708 WG, The Netherlands. sami.sahin@wur.nl.
authors.forename: Sami
authors.initials: S
authors.lastname: Sahin
authors.affiliation: Departament d'Enginyeria Química, Escola Tècnica Superior d'Enginyeria Química, Universitat Rovira i Virgili, Avda. Països Catalans 26, Tarragona 43007, Spain. carme.guell@urv.cat.
authors.forename: Carme
authors.initials: C
authors.lastname: Güell
keywords: contact angle; emulsification; microfluidics; process stability; wettability changes