456293 Microfluidic Mass Transfer Process Intensification for Micron Droplet Generation with Dilute Surfactant Concentration

Wednesday, November 16, 2016: 2:30 PM
Union Square 23 & 24 (Hilton San Francisco Union Square)
Yankai Li1, Kai Wang2, Jianhong Xu3 and Guangsheng Luo1, (1)Department of Chemical Engineering, The State Key Laboratory of Chemical Engineering, Tsinghua University, Beijing, China, (2)Department of Chemical Engineering, Tsinghua University, Beijing, China, (3)Chemical Engneering, The State Key Laboratory of Chemical Engineering, Beijing, China

Microfluidic emulsification always involves fresh interface formation during droplet generation, which induces surfactant mass transfer and thus dynamic interfacial tensions (IFTs). As surfactant transfer onto freshly created interface often limits decrease of IFTs and droplet sizes, excessive amounts of surfactant would usually be added to speed up surfactant transfer and eliminate dynamic effects. Here we have systematically investigated the dynamic effects of surfactants in our newly designed capillary embedded T-junction microfluidic device. Within the asymmetric devices, hydrodynamic forces would intensify surfactant molecules concentrating to the point of droplet break-up, leading to extremely low dynamic IFTs temporarily (~0mN/m). Micron droplets could thus be generated with dilute surfactant concentrations (dynamic effects would be eliminated with surfactant concentrations of SDS 0.05wt% 1/6 CMC, Tween20 0.20wt% 4/7 CMC, F68 0.20wt% 2/3 CMC). The presented results provide us with more in-depth understanding of dynamic effects of surfactants as well as a novel method for surfactant mass transfer intensification and thus micron droplet generation with dilute surfactant concentrations.

Extended Abstract: File Not Uploaded
See more of this Session: Dynamic Processes at Interfaces
See more of this Group/Topical: Engineering Sciences and Fundamentals