Effects of vertical confinement on the flow of polymer solutions in planar constriction microchannels

Raihan, Mahmud Kamal; Wu, Sen; Dort, Heston; Baghdady, Micah; Song, Yongxin; Xuan, Xiangchun

doi:10.1039/d2sm01024k

Cited by 10 publications

(7 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As viewed from the timelapses on top of the images, the electrokinetic motion of particles slows down in the PEO solution (Figure 1b) compared to that in the Newtonian solution (Figure 1a). This observation is consistent with our previous studies, 45,47,50 which can be attributed to the polymer contribution to viscosity and polymer-induced elasticity. 52 The electrokinetic velocity remains nearly independent of the particle size in the Newtonian solution because the lines tracking the positions of different particles exhibit a parallel alignment in Figure 1a.…”

Section: Resultssupporting

confidence: 94%

“…In comparison to 1000 ppm PEO in Figure 2b, we see a decrease in both V eo and V ek with the increase of PEO concentration. This trend is consistent with our recent observation, 50 which, as noted above, should arise from the increased fluid viscosity and elasticity effect (see Table 1). 52 Moreover, we observe an intensified dependence of V ek on the particle size as the PEO concentration increases from 500 ppm (Figure 3a) to 1000 ppm (Figure 2b) and 2000 ppm (Figure 3b).…”

Section: Effect Of the Polymer Concentrationsupporting

confidence: 93%

“…To put together the results for the effects of polymer concentration and length into one plot for a unified understanding, we employ the so-called elasticity number, El, to characterize the fluid elasticity effect. This dimensionless number is defined as the ratio of the Weissenberg number to the Reynolds number and is independent of the fluid kinematics, as given by 50,58,61…”

Section: Summary Of the Effect Of Fluid Elasticitymentioning

confidence: 99%

See 2 more Smart Citations

Particle Size-Dependent Electrophoresis in Polymer Solutions

Bentor,

Xuan

2024

Anal. Chem.

View full text Add to dashboard Cite

It has long been known that the electrophoretic velocity of a charged particle is independent of its size under the thin-Debye-layer limit. This so-called Smoluchowski velocity is, however, valid only for Newtonian fluids. A couple of recent theoretical studies predict the rheology-induced particle size dependence of electrophoresis in non-Newtonian fluids. This work presents the first experimental demonstration of such dependence in viscoelastic poly(ethylene oxide) (PEO) solutions. Three different-sized particles are observed to travel at the same electrophoretic velocity in a Newtonian buffer through a rectangular microchannel. In contrast, their measured electrophoretic velocities in the PEO solution exhibit an increasing trend for larger particles, which is consistent with theoretical prediction. This particle size dependence is found to grow with an increasing concentration or length of the PEO polymer. Both trends are attributed to enhanced fluid elasticity, as characterized by the increasing elasticity number.

show abstract

Section: Resultssupporting

confidence: 94%

Section: Effect Of the Polymer Concentrationsupporting

confidence: 93%

Section: Summary Of the Effect Of Fluid Elasticitymentioning

confidence: 99%

See 1 more Smart Citation

Particle Size-Dependent Electrophoresis in Polymer Solutions

Bentor,

Xuan

2024

Anal. Chem.

View full text Add to dashboard Cite

show abstract

“…Microfluidic focusing techniques, which provide a precise control of fluid behavior at the microscale, have recently become highly sought-after for high-throughput focusing of particles/cells. − Derived from the source of the operational forces, these remarkable techniques can be categorized into active and passive types. Active focusing techniques, such as magnetophoresis, dielectrophoresis, and acoustophoresis, require external energy sources for a more accurate manipulation of the target samples. − In contrast, passive focusing techniques are based on internal hydrodynamics or channel geometry, such as lateral displacement, geometrical effects, and inertial effects, which make them simpler to fabricate, maintain, and operate at higher flow rates. , …”

Section: Introductionmentioning

confidence: 99%

Spiral Large-Dimension Microfluidic Channel for Flow-Rate- and Particle-Size-Insensitive Focusing by the Stabilization and Acceleration of Secondary Flow

Shen,

Zhao,

Bai

et al. 2024

Anal. Chem.

View full text Add to dashboard Cite

Inertial microfluidics has demonstrated its ability to focus particles in a passive and straightforward manner. However, achieving flow-rate-and particle-size-insensitive focusing in largedimension channels with a simple design remains challenging. In this study, we developed a spiral microfluidic with a large-dimension channel to achieve inertial focusing. By designing a unique "big buffering area" and a "small buffering area" in the spiral microchannel, we observed the stabilization and acceleration of secondary flow. Our optimized design allowed for efficient (>99.9%) focusing of 15 μm particles within a wide range of flow rates (0.5− 4.5 mL/min) during a long operation duration (0−60 min). Additionally, we achieved effective (>95%) focusing of differentsized particles (7, 10, 15, and 30 μm) and three types of tumor cells (K562, HeLa, and MCF-7) near the inner wall of the 1 mm wide outlet when applying different flow rates (1−3 mL/min). Finally, successful 3D cell focusing was achieved within an optimized device, with the cells positioned at a distance of 50 μm from the wall. Our strategy of stabilizing and accelerating Dean-like secondary flow through the unique configuration of a "big buffering area" and a "small buffering area" proved to be highly effective in achieving inertial focusing that is insensitive to the flow rate and particle size, particularly in large-dimension channels. Consequently, it shows great potential for use in hand-operated microfluidic tools for flow cytometry.

show abstract

“…Flow-focusing channels have previously been used for various fractionation techniques that rely on particle-wall repulsion, including inertial focusing, 13 viscoelastic lift, 14,15 pinched-flow fractionation, 16,17 or combinations of phenomena. [18][19][20] CPEO flow induced separation is a new dimension that can be exploited for tunable wall repulsion by controlling the external AC electric field requiring no extra complexity in device fabrication.…”

Section: Introductionmentioning

confidence: 99%