View source for Photoreactive coating for high-contrast spatial patterning of microfluidic device wettability

[[Photoreactive coating for high-contrast spatial patterning of microfluidic device wettability]] 

Authors: Adam R. Abate, Amber T. Krummel, Daeyeon Lee, Manuel Marquez, Christian Holtzed and
David A. Weitz

Lab Chip, 2008, 8, 2157–2160

====Soft matter keywords====



By Alex Epstein
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===Abstract from the original paper===

For many applications in microfluidics, the wettability of the devices
must be spatially controlled. We introduce a photoreactive sol–gel
coating that enables high-contrast spatial patterning of microfluidic
device wettability.

==Soft matters==



[[Image:photofig1.png|thumb|left|400px|'''Fig. 1''' Contact angle measurement of water droplets in air on (a) sol–gel
coated substrate with contact angle 105 deg and (b) PAA grafted substrate
with contact angle 22 deg. AFM images of (c) sol–gel coated and (d) PAA
grafted microchannels. The images show a 10 deg 20 mm area at high
resolution; the dark to light color scale maps to feature heights of -150 to
150 nm. (e) Surface concentrations of atoms on sol–gel coated and PAA
functionalized substrates, measured with XPS; fluorine (F 1s), oxygen (O
1s), carbon (C 1s), and silicon (Si 2s).]]