Difference between revisions of "Photoreactive coating for high-contrast spatial patterning of microfluidic device wettability"

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[[Image:photofig2.png|thumb|right|400px|'''Fig. 1''' SEM images of channel cross sections; scale bars denote 5 mm. (a)
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[[Image:photofig2.png|thumb|left|400px|'''Fig. 1''' SEM images of channel cross sections; scale bars denote 5 mm. (a)
 
Uncoated PDMS channel cross-section and (b) magnified view of upper
 
Uncoated PDMS channel cross-section and (b) magnified view of upper
 
right corner. (c) Coated, PAA functionalized PDMS channel and (d)
 
right corner. (c) Coated, PAA functionalized PDMS channel and (d)
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sol–gel wets the surface and collects in regions of high curvature.]]
 
sol–gel wets the surface and collects in regions of high curvature.]]
  
[[Image:photofig1.png|thumb|left|400px|'''Fig. 2''' Contact angle measurement of water droplets in air on (a) sol–gel
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[[Image:photofig1.png|thumb|right|400px|'''Fig. 2''' Contact angle measurement of water droplets in air on (a) sol–gel
 
coated substrate with contact angle 105 deg and (b) PAA grafted substrate
 
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
 
with contact angle 22 deg. AFM images of (c) sol–gel coated and (d) PAA
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functionalized substrates, measured with XPS; fluorine (F 1s), oxygen (O
 
functionalized substrates, measured with XPS; fluorine (F 1s), oxygen (O
 
1s), carbon (C 1s), and silicon (Si 2s).]]
 
1s), carbon (C 1s), and silicon (Si 2s).]]
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 +
[[Image:photofig3.png|thumb|left|300px|'''Fig. 3''' (a) Photomicrograph of a sol–gel coated channel. PAA has been
 +
grafted to the right half of the channel using UV-initiated graft polymerization.
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The grafted polymer is dyed with toluidine blue, a dye that
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preferentially stains PAA. (b) Average grayscale intensity across the
 +
channel as a function of location along the channel.]]

Revision as of 13:59, 1 March 2009

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


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

Fig. 1 SEM images of channel cross sections; scale bars denote 5 mm. (a) Uncoated PDMS channel cross-section and (b) magnified view of upper right corner. (c) Coated, PAA functionalized PDMS channel and (d) magnified view of upper right corner; the corner is rounded because the sol–gel wets the surface and collects in regions of high curvature.
Fig. 2 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).
Fig. 3 (a) Photomicrograph of a sol–gel coated channel. PAA has been grafted to the right half of the channel using UV-initiated graft polymerization. The grafted polymer is dyed with toluidine blue, a dye that preferentially stains PAA. (b) Average grayscale intensity across the channel as a function of location along the channel.