Aging Effects on Oxidized and Amine-Modified Poly(dimethylsiloxane) Surfaces Studied with Chemical Force Titrations:  Effects on Electroosmotic Flow Rate in Microfluidic Channels

Langmuir ◽  
2003 ◽  
Vol 19 (23) ◽  
pp. 9792-9798 ◽  
Author(s):  
Bin Wang ◽  
Lu Chen ◽  
Zamin Abdulali-Kanji ◽  
J. Hugh Horton ◽  
Richard D. Oleschuk
Keyword(s):  
Flow Rate ◽  
Electroosmotic Flow ◽  
Microfluidic Channels ◽  
Aging Effects ◽  
Chemical Force

Sulfonated-polydimethylsiloxane (PDMS) microdevices with enhanced electroosmotic pumping and stability

2006 ◽  
Vol 84 (4) ◽  
pp. 720-729 ◽  
Author(s):  
Bin Wang ◽  
J Hugh Horton ◽  
Richard D Oleschuk
Keyword(s):  
Electroosmotic Flow ◽  
Aging Effect ◽  
Polymer Materials ◽  
Air Plasma ◽  
Aging Effects ◽  
Pdms Surface ◽  
Electroosmotic Pumping ◽  
Modified Surface ◽  
Pdms Chip ◽  
Chemical Force

Polydimethylsiloxane (PDMS) microfluidic devices offer several advantages in terms of cost and ease of fabrication compared with those fabricated from both glass and silicon materials. PDMS, however, has some potential disadvantages compared with other materials including high hydrophobicity, which makes filling the micron-sized channels difficult, and minimal surface charge resulting in reduced electroosmotic flow (EOF). Here, we describe the oxidation of the PDMS surface to form silanol groups using both air plasma and a discharge from a Tesla coil, and subsequent modification to form sulfonated-PDMS surfaces. The flow performance of freshly prepared and aged sulfonated-PDMS chips was determined at pH 5 and compared with those of unmodified and oxidized PDMS chips. The electroosmotic mobility (µeo) for a sulfonated-PDMS microdevice was determined at various pH values (pH 3~8) and compared with that for an oxidized PDMS chip. The lower pKa of a sulfonic acid modified surface compared with a silanol modified surface generated a stronger EOF over the entire pH range studied. Chemical force titrations were used to characterize the changes in functional groups present on the surface of freshly prepared and aged sulfonated-PDMS surfaces. These experiments show that the sulfonated-PDMS is a superior material for use in microfluidic applications because (i) it supports EOF over a much wider range of pH than similar polymer materials and (ii) is less susceptible to degradation of its EOF rate owing to air aging effects and surface reorganization.Key words: polydimethylsiloxane (PDMS), sulfonated surface modification, electroosmotic flow (EOF), aging effect, chemical force titrations.

Electroosmotic Flow in Hydrophobic Microchannels of General Cross Section

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Morteza Sadeghi ◽  
Arman Sadeghi ◽  
Mohammad Hassan Saidi
Keyword(s):  
Cross Section ◽  
Flow Rate ◽  
Electroosmotic Flow ◽  
Slip Length ◽  
Debye Length ◽  
Surface Hydrophobicity ◽  
Double Layers ◽  
Slip Conditions ◽  
Wall Boundary Conditions ◽  
Electroosmotic Velocity

Adopting the Navier slip conditions, we analyze the fully developed electroosmotic flow in hydrophobic microducts of general cross section under the Debye–Hückel approximation. The method of analysis includes series solutions which their coefficients are obtained by applying the wall boundary conditions using the least-squares matching method. Although the procedure is general enough to be applied to almost any arbitrary cross section, eight microgeometries including trapezoidal, double-trapezoidal, isosceles triangular, rhombic, elliptical, semi-elliptical, rectangular, and isotropically etched profiles are selected for presentation. We find that the flow rate is a linear increasing function of the slip length with thinner electric double layers (EDLs) providing higher slip effects. We also discover that, unlike the no-slip conditions, there is not a limit for the electroosmotic velocity when EDL extent is reduced. In fact, utilizing an analysis valid for very thin EDLs, it is shown that the maximum electroosmotic velocity in the presence of surface hydrophobicity is by a factor of slip length to Debye length higher than the Helmholtz–Smoluchowski velocity. This approximate procedure also provides an expression for the flow rate which is almost exact when the ratio of the channel hydraulic diameter to the Debye length is equal to or higher than 50.

Solute Dispersion by Electroosmotic flow in Nonuniform Microfluidic Channels

2001 ◽  
pp. 615-616 ◽  
Author(s):  
M. T. Blom ◽  
E. F. Hasselbrink ◽  
H. Wensink ◽  
A. van den Berg
Keyword(s):  
Electroosmotic Flow ◽  
Microfluidic Channels ◽  
Solute Dispersion

scholarly journals Analytical Solution for Heat Transfer in Electroosmotic Flow of a Carreau Fluid in a Wavy Microchannel

2019 ◽  
Vol 9 (20) ◽  
pp. 4359 ◽  
Author(s):  
Saima Noreen ◽  
Sadia Waheed ◽  
Abid Hussanan ◽  
Dianchen Lu
Keyword(s):  
Fluid Flow ◽  
Flow Pattern ◽  
Flow Rate ◽  
Electroosmotic Flow ◽  
Linear Problem ◽  
Perturbation Technique ◽  
Volumetric Flow Rate ◽  
Carreau Fluid ◽  
Long Wavelength ◽  
Wide Range

This article explores the heat and transport characteristics of electroosmotic flow augmented with peristaltic transport of incompressible Carreau fluid in a wavy microchannel. In order to determine the energy distribution, viscous dissipation is reckoned. Debye Hückel linearization and long wavelength assumptions are adopted. Resulting non-linear problem is analytically solved to examine the distribution and variation in velocity, temperature and volumetric flow rate within the Carreau fluid flow pattern through perturbation technique. This model is also suitable for a wide range of biological microfluidic applications and variation in velocity, temperature and volumetric flow rate within the Carreau fluid flow pattern.

Electroosmotic Flow Rate: A Semiempirical Approach

2000 ◽  
pp. 247-266 ◽  
Author(s):  
J. H. Chang ◽  
Z. Qiang ◽  
C. P. Huang ◽  
D. Cha
Keyword(s):  
Flow Rate ◽  
Electroosmotic Flow ◽  
Semiempirical Approach

Fundamentals of elasto-inertial particle focusing in curved microfluidic channels

Lab on a Chip ◽  
2016 ◽  
Vol 16 (14) ◽  
pp. 2626-2635 ◽  
Author(s):  
Nan Xiang ◽  
Xinjie Zhang ◽  
Qing Dai ◽  
Jie Cheng ◽  
Ke Chen ◽  
...  
Keyword(s):  
Flow Rate ◽  
Process Model ◽  
Microfluidic Channels ◽  
Inertial Particle ◽  
Particle Focusing ◽  
Stage Process

We experimentally explore the elasto-inertial particle focusing in curved microfluidic channels and propose a six-stage process model illustrating the particle focusing with increasing flow rate.

scholarly journals Precision control of flow rate in microfluidic channels using photoresponsive soft polymer actuators

Lab on a Chip ◽  
2017 ◽  
Vol 17 (11) ◽  
pp. 2013-2021 ◽  
Author(s):  
Colm Delaney ◽  
Peter McCluskey ◽  
Simon Coleman ◽  
Jeffrey Whyte ◽  
Nigel Kent ◽  
...  
Keyword(s):  
Flow Rate ◽  
Microfluidic Channels ◽  
Precision Control ◽  
Polymer Actuators ◽  
Pid Algorithm ◽  
Control Of Flow ◽  
Soft Polymer

Precision control of flow using photoresponsive hydrogels within fluidic channels was demonstrated by applying a PID algorithm.

scholarly journals Doppler-Based Flow Rate Sensing in Microfluidic Channels

Sensors ◽  
2014 ◽  
Vol 14 (9) ◽  
pp. 16799-16807 ◽  
Author(s):  
Liron Stern ◽  
Avraham Bakal ◽  
Mor Tzur ◽  
Maya Veinguer ◽  
Noa Mazurski ◽  
...  
Keyword(s):  
Flow Rate ◽  
Microfluidic Channels
Sign in / Sign up

Export Citation Format

Share Document