Sequential droplet manipulation via vibrating ratcheted microchannels

This work reports on a simple scheme for transport and sequential manipulation of droplets using ratchet-shaped microchannels. Once subjected to lateral vibration through a sinusoidal shaker with a controllable frequency and amplitude, droplets move along the direction of least resistance with velocities depending on vibration parameters (amplitude and frequency), channel geometry and material properties, and the angle between the channel and vibration direction (lateral offset angle). Using channels having different lateral offset angles, we achieved a controllable time delay between the transports of various droplets. Based on the same principal, we also designed a multi-functional droplet manipulation platform with the capability to transport, collect, mix, and discharge several droplets.

[1]  Robin H. Liu,et al.  Microfluidic tectonics: a comprehensive construction platform for microfluidic systems. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[2]  Yutaka Sumino,et al.  Self-running droplet: emergence of regular motion from nonequilibrium noise. , 2004, Physical review letters.

[3]  Reinhard Lipowsky,et al.  Wetting morphologies at microstructured surfaces. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[4]  Ichimura,et al.  Light-driven motion of liquids on a photoresponsive surface , 2000, Science.

[5]  John Ralston,et al.  Reversible Wettability of Photoresponsive Pyrimidine-Coated Surfaces , 1999 .

[6]  Jean Berthier,et al.  Microdrops and digital microfluidics , 2008 .

[7]  George M. Whitesides,et al.  How to Make Water Run Uphill , 1992, Science.

[8]  Françoise Brochard-Wyart,et al.  Motions of droplets on hydrophobic model surfaces induced by thermal gradients , 1993 .

[9]  F. Heslot,et al.  Fingering instability of thin spreading films driven by temperature gradients , 1990, Nature.

[10]  Aa Anton Darhuber,et al.  PRINCIPLES OF MICROFLUIDIC ACTUATION BY MODULATION OF SURFACE STRESSES , 2005 .

[11]  B. Ziaie,et al.  High-resolution technique for fabricating environmentally sensitive hydrogel microstructures. , 2004, Langmuir : the ACS journal of surfaces and colloids.

[12]  Peter R C Gascoyne,et al.  Dielectrophoresis-based programmable fluidic processors. , 2004, Lab on a chip.

[13]  O. Velev,et al.  On-chip manipulation of free droplets , 2003, Nature.

[14]  P. Tarazona.  Capillarity and Wetting , 1987 .

[15]  P. Gennes,et al.  Capillarity and Wetting Phenomena , 2004 .

[16]  S. Cho,et al.  Creating, transporting, cutting, and merging liquid droplets by electrowetting-based actuation for digital microfluidic circuits , 2003 .

[17]  Shah,et al.  Electrochemical principles for active control of liquids on submillimeter scales , 1999, Science.