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Light‐Governed Capillary Flow in Microfluidic Systems
Author(s) -
Jiang Li,
Erickson David
Publication year - 2013
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201201778
Subject(s) - polydimethylsiloxane , microfluidics , materials science , capillary action , flow (mathematics) , wetting , volumetric flow rate , nanotechnology , optoelectronics , mechanics , composite material , physics
Light‐based flow systems for point‐of‐care devices are of interest because, in principle, sunlight could be used to operate them, potentially allowing for high functionality with minimal device complexity and expense. A light‐operated method to drive flow using poly( N ‐isopropylacrylamide), a ‘smart’ polymer that changes wettability as a function of temperature, is introduced. It is grafted onto a carbon black‐polydimethylsiloxane surface, which converts light into a thermal pattern that valves flow at user‐defined locations. Flow rates are demonstrated ranging from 4 μL min −1 at 25 °C to 0.1 μL min −1 at 40 °C. The valving dynamics are also characterised, and a response time of less than 4 s is shown. Light‐operated flow could provide the simple architecture and advanced functionality needed in low‐resource point‐of‐care devices.