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Nanoscale surface modifications to control capillary flow characteristics in PMMA microfluidic devices.

Mukhopadhyay S, Roy SS, D'Sa RA, Mathur A, Holmes RJ, McLaughlin JA - Nanoscale Res Lett (2011)

Bottom Line: Experimental results presented in detail the surface modifications in the form of distinct changes in the static water contact angle across a range from 44.3 to 81.2 when compared to pristine PMMA surfaces.Additionally, capillary flow of water (dyed to aid visualization) through the microfluidic devices was recorded and analyzed to provide comparison data between filling time of a microfluidic chamber and surface modification characteristics, including the effects of surface energy and surface roughness on the microfluidic flow.We have experimentally demonstrated that fluid flow and thus filling time for the microfluidic device was significantly faster for the device with surface modifications that resulted in a lower static contact angle, and also that the incorporation of micro-pillars into a fluidic device increases the filling time when compared to comparative devices.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanotechnology and Integrated Bio-Engineering Center, School of Engineering, University of Ulster, Jordanstown, Co Antrim, BT37 0QB, Northern Ireland, UK. s.sinha-roy@ulster.ac.uk.

ABSTRACT
Polymethylmethacrylate (PMMA) microfluidic devices have been fabricated using a hot embossing technique to incorporate micro-pillar features on the bottom wall of the device which when combined with either a plasma treatment or the coating of a diamond-like carbon (DLC) film presents a range of surface modification profiles. Experimental results presented in detail the surface modifications in the form of distinct changes in the static water contact angle across a range from 44.3 to 81.2 when compared to pristine PMMA surfaces. Additionally, capillary flow of water (dyed to aid visualization) through the microfluidic devices was recorded and analyzed to provide comparison data between filling time of a microfluidic chamber and surface modification characteristics, including the effects of surface energy and surface roughness on the microfluidic flow. We have experimentally demonstrated that fluid flow and thus filling time for the microfluidic device was significantly faster for the device with surface modifications that resulted in a lower static contact angle, and also that the incorporation of micro-pillars into a fluidic device increases the filling time when compared to comparative devices.

No MeSH data available.


SEM images of a microfluidic channel with 300 μm pillars. (a) Closure image of 300 μm pillars; (b) arrays of 300 μm pillars; (c) 300 μm pillars in the regions just after the inlet; and (d) 300 μm pillars in the region just before the outlet.
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Figure 2: SEM images of a microfluidic channel with 300 μm pillars. (a) Closure image of 300 μm pillars; (b) arrays of 300 μm pillars; (c) 300 μm pillars in the regions just after the inlet; and (d) 300 μm pillars in the region just before the outlet.

Mentions: The PMMA microchannels described above were fabricated in two categories: (i) planar faces with no micro-pillar structures present on any of the walls of the device, (ii) planar faces on all but the lower wall, where micro-pillar features were hot-embossed. The micro-pillars were used as surface roughness elements [2,22] with a height of 15 μm, and were fabricated from the beginning of region 3 and to the end of region 5, as arrays of 100 m (1.6% increase per mm2), 200 m (1.9% increase per mm2), or 300 m pillars (1.8% increase per mm2), with an inter-pillar separation (horizontal distance between any two subsequent micropillars) of 200 μm. Figure 2 shows example of SEM images of microchannel containing pillars of 300 μm in width.


Nanoscale surface modifications to control capillary flow characteristics in PMMA microfluidic devices.

Mukhopadhyay S, Roy SS, D'Sa RA, Mathur A, Holmes RJ, McLaughlin JA - Nanoscale Res Lett (2011)

SEM images of a microfluidic channel with 300 μm pillars. (a) Closure image of 300 μm pillars; (b) arrays of 300 μm pillars; (c) 300 μm pillars in the regions just after the inlet; and (d) 300 μm pillars in the region just before the outlet.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211507&req=5

Figure 2: SEM images of a microfluidic channel with 300 μm pillars. (a) Closure image of 300 μm pillars; (b) arrays of 300 μm pillars; (c) 300 μm pillars in the regions just after the inlet; and (d) 300 μm pillars in the region just before the outlet.
Mentions: The PMMA microchannels described above were fabricated in two categories: (i) planar faces with no micro-pillar structures present on any of the walls of the device, (ii) planar faces on all but the lower wall, where micro-pillar features were hot-embossed. The micro-pillars were used as surface roughness elements [2,22] with a height of 15 μm, and were fabricated from the beginning of region 3 and to the end of region 5, as arrays of 100 m (1.6% increase per mm2), 200 m (1.9% increase per mm2), or 300 m pillars (1.8% increase per mm2), with an inter-pillar separation (horizontal distance between any two subsequent micropillars) of 200 μm. Figure 2 shows example of SEM images of microchannel containing pillars of 300 μm in width.

Bottom Line: Experimental results presented in detail the surface modifications in the form of distinct changes in the static water contact angle across a range from 44.3 to 81.2 when compared to pristine PMMA surfaces.Additionally, capillary flow of water (dyed to aid visualization) through the microfluidic devices was recorded and analyzed to provide comparison data between filling time of a microfluidic chamber and surface modification characteristics, including the effects of surface energy and surface roughness on the microfluidic flow.We have experimentally demonstrated that fluid flow and thus filling time for the microfluidic device was significantly faster for the device with surface modifications that resulted in a lower static contact angle, and also that the incorporation of micro-pillars into a fluidic device increases the filling time when compared to comparative devices.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanotechnology and Integrated Bio-Engineering Center, School of Engineering, University of Ulster, Jordanstown, Co Antrim, BT37 0QB, Northern Ireland, UK. s.sinha-roy@ulster.ac.uk.

ABSTRACT
Polymethylmethacrylate (PMMA) microfluidic devices have been fabricated using a hot embossing technique to incorporate micro-pillar features on the bottom wall of the device which when combined with either a plasma treatment or the coating of a diamond-like carbon (DLC) film presents a range of surface modification profiles. Experimental results presented in detail the surface modifications in the form of distinct changes in the static water contact angle across a range from 44.3 to 81.2 when compared to pristine PMMA surfaces. Additionally, capillary flow of water (dyed to aid visualization) through the microfluidic devices was recorded and analyzed to provide comparison data between filling time of a microfluidic chamber and surface modification characteristics, including the effects of surface energy and surface roughness on the microfluidic flow. We have experimentally demonstrated that fluid flow and thus filling time for the microfluidic device was significantly faster for the device with surface modifications that resulted in a lower static contact angle, and also that the incorporation of micro-pillars into a fluidic device increases the filling time when compared to comparative devices.

No MeSH data available.