title: Enhanced Dissolution of Liquid Microdroplets in the Extensional Creeping Flow of a Hydrodynamic Trap.
abstract: A novel noncontact technique based on hydrodynamic trapping is presented to study the dissolution of freely suspended liquid microdroplets into a second immiscible phase in a simple extensional creeping flow. Benzyl benzoate (BB) and n-decanol microdroplets are individually trapped at the stagnation point of a planar extensional flow, and dissolution of single microdroplets into an aqueous solution containing surfactant is characterized at different flow rates. The experimental dissolution curves are compared to two models: (i) the Epstein-Plesset (EP) model which considers only diffusive mass transfer, and (ii) the Zhang-Yang-Mao (ZYM) model which considers both diffusive and convective mass transfer in the presence of extensional creeping flow. The EP model significantly underpredicts the experimentally determined dissolution rates for all experiments. In contrast, very good agreement is observed between the experimental dissolution curves and the ZYM model when the saturation concentration of the microdroplet liquid (cs) is used as the only fitting parameter. Experiments with BB microdroplets at low surfactant concentration (10 μM) reveal cs values very similar to that reported in the literature. In contrast, experiments with BB and n-decanol microdroplets at 10 mM surfactant concentration, higher than the critical micelle concentration (CMC) of 5 mM, show further enhancements in microdroplet dissolution rates due to micellar solubilization. The presented method accurately tests the dissolution of single microdroplets into a second immiscible phase in extensional creeping flow and has potential for applications such as separation processes, food dispersion, and drug development/design.
authors: Adil
authors: A
authors: Mustafa
authors: Ahmet
authors: A
authors: Erten
authors: Rana M Armaghan
authors: RM
authors: Ayaz
authors: Oğuz
authors: O
authors: Kayıllıoğlu
authors: Aysenur
authors: A
authors: Eser
authors: Mustafa
authors: M
authors: Eryürek
authors: Muhammad
authors: M
authors: Irfan
authors: Metin
authors: M
authors: Muradoglu
authors: Department of Electrical and Electronics Engineering, Istanbul Sehir University , 34662 Uskudar, Istanbul Turkey.
authors: Melikhan
authors: M
authors: Tanyeri
authors: Alper
authors: A
authors: Kiraz