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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.


Schematic (top view) of the microfluidic device, with proper length of each region.
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Figure 1: Schematic (top view) of the microfluidic device, with proper length of each region.

Mentions: Figure 1 represents the schematic of the microchannels used to study the effects of different surface properties (surface wettability and surface roughness) on flow through microfluidic channels, with amaranth dye (Sigma Aldrich, UK) used to aid visualization of the water meniscus. The microchannel dimensions following hot embossing were verified using a Dektak 8 profilometer (Vecco Instruments, Santa Barbara, CA, USA). The microchannel design [2,11] shown in Figure 1 can be described as follows Regions 1 and 6 are circular inlets and outlets with a diameter of 2 mm. Region 2 has uniform width of 1.5 mm, while the width of region 3 increases from 1.5 to 5.0 mm. Region 4 (the chamber) has the length of 6 mm and width of 5 mm, and region 5 decreases from 5 to 1.5 mm in width. Each of the regions 2, 3, and 5 has a length of 2 mm along the channel axis and the height of the microchannel across all regions is 33 μm.


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)

Schematic (top view) of the microfluidic device, with proper length of each region.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Schematic (top view) of the microfluidic device, with proper length of each region.
Mentions: Figure 1 represents the schematic of the microchannels used to study the effects of different surface properties (surface wettability and surface roughness) on flow through microfluidic channels, with amaranth dye (Sigma Aldrich, UK) used to aid visualization of the water meniscus. The microchannel dimensions following hot embossing were verified using a Dektak 8 profilometer (Vecco Instruments, Santa Barbara, CA, USA). The microchannel design [2,11] shown in Figure 1 can be described as follows Regions 1 and 6 are circular inlets and outlets with a diameter of 2 mm. Region 2 has uniform width of 1.5 mm, while the width of region 3 increases from 1.5 to 5.0 mm. Region 4 (the chamber) has the length of 6 mm and width of 5 mm, and region 5 decreases from 5 to 1.5 mm in width. Each of the regions 2, 3, and 5 has a length of 2 mm along the channel axis and the height of the microchannel across all regions is 33 μm.

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.