title: Enhancement of electrokinetically driven microfluidic T-mixer using frequency modulated electric field and channel geometry effects.
abstract: This study reports improved electrokinetically driven microfluidic T-mixers to enhance their mixing efficiency. Enhancement of electrokinetic microfluidic T-mixers is achieved using (i) an active approach of utilizing a pulsating EOF, and (ii) a passive approach of using the channel geometry effect with patterned blocks. PDMS-based electrokinetic T-mixers of different designs were fabricated. Experimental measurements were carried out using Rhodamine B to examine the mixing performance and the micro-particle image velocimetry technique to characterize the electrokinetic flow velocity field. Scaling analysis provides an effective frequency range of applied AC electric field. Results show that for a T-mixer of 10 mm mixing length, utilizing frequency modulated electric field and channel geometry effects can increase the mixing efficiency from 50 to 90%. In addition, numerical simulations were performed to analyze the mixing process in the electrokinetic T-mixers with various designs. The simulation results were compared with the experimental data, and reasonable agreement was found.
authors.affiliation: School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore.
authors.forename: Deguang
authors.initials: D
authors.lastname: Yan
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
authors.forename: Jianmin
authors.initials: J
authors.lastname: Miao
authors.forename: Yeecheong
authors.initials: Y
authors.lastname: Lam
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Huang
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004574:Electromagnetic Fields; D053841:Electroosmosis / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D008962:Models, Theoretical