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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.


Surface energy versus static water contact angle.
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Figure 3: Surface energy versus static water contact angle.

Mentions: where θ is the contact angle of the liquid on the solid surface; γsd and γsp are the dispersion and polar components of surface free energy of the solid surface, respectively; γlis the surface free energy of the liquid; γld and γlp are the dispersion and polar components of surface free energy of the liquid surface, respectively. The calculated surface energies as a function of static water contact angle are shown in Figure 3, where in general, the static water contact angle decreases as the polar component of surface free energy (solid surface) increases [37-40]. Figure 3 also illustrates that the surface energy for both PMMA and DLC-coated PMMA were similar; however, Si-doped DLC demonstrated an increased surface energy when compared to pristine PMMA.


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)

Surface energy versus static water contact angle.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Surface energy versus static water contact angle.
Mentions: where θ is the contact angle of the liquid on the solid surface; γsd and γsp are the dispersion and polar components of surface free energy of the solid surface, respectively; γlis the surface free energy of the liquid; γld and γlp are the dispersion and polar components of surface free energy of the liquid surface, respectively. The calculated surface energies as a function of static water contact angle are shown in Figure 3, where in general, the static water contact angle decreases as the polar component of surface free energy (solid surface) increases [37-40]. Figure 3 also illustrates that the surface energy for both PMMA and DLC-coated PMMA were similar; however, Si-doped DLC demonstrated an increased surface energy when compared to pristine PMMA.

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.