title: Electrorheological fluid and its applications in microfluidics.
abstract: Microfluidics is a low-cost technique for fast-diagnosis and microsynthesis. Within a decade it might become the foundation of point-of-care and lab-on-a-chip applications. With microfluidic chips, high-throughput sample screening and information processing are made possible. The picoliter droplet runs in microfluidic chips are ideal miniaturized vessels for microdetection and microsynthesis. Meanwhile, individual manipulation of microdroplets remains a challenge: the shortcomings in automatic, reliable, and scalable methods for logic control prevent further integration of microfluidic applications. The giant electrorheological fluid (GERF), which is a kind of "smart" colloid, has tunable viscosity under the influence of external electric field. Therefore, GERF is introduced as the active controlling medium, with real-time response in on-chip fluid control. This review article introduces the working principles and fabrication methods of different types of electrorheological fluid, and extensively describes the strategies of GERF-assisted microfluidic controlling schemes.
authors.affiliation: Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Limu
authors.initials: L
authors.lastname: Wang
authors.forename: Xiuqing
authors.initials: X
authors.lastname: Gong
authors.forename: Weijia
authors.initials: W
authors.lastname: Wen
mesh_terms: D055664:Electrochemical Techniques / Q000295:instrumentation* / Q000379:methods*; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods*; D008962:Models, Theoretical