Particle Shape-Dependent Electrophoresis in Viscoelastic Fluids.
Joseph Bentor1, Seyed Mojtaba Tabarhoseini1, Yongxin Song2
1Department of Mechanical Engineering, Clemson University, Clemson, South Carolina 29634-0921, United States.
Analytical Chemistry
|May 18, 2026
Summary
Fluid elasticity, not particle size, dictates electrophoretic velocity in viscoelastic solutions. Particle shape significantly impacts velocity in non-Newtonian fluids, unlike in Newtonian fluids.
Area of Science:
- Physics
- Chemistry
- Biotechnology
Background:
- Electrophoretic velocity is typically independent of particle size and shape in Newtonian fluids.
- Previous work identified particle size-dependent electrophoresis in viscoelastic poly(ethylene oxide) solutions.
- Fluid elasticity's role in particle shape-dependent electrophoresis requires further investigation.
Purpose of the Study:
- To investigate the influence of fluid elasticity on particle shape-dependent electrophoresis.
- To determine if particle shape affects electrophoretic velocity in viscoelastic fluids.
- To explore potential applications in microfluidic separation technologies.
Main Methods:
- Experimental measurements of electrophoretic velocity for particles of varying shapes (sphere, pear, peanut) in poly(ethylene oxide) solutions.
- Comparison of results in viscoelastic fluids versus Newtonian fluids.
- Systematic variation of polymer concentration to assess the effect of fluid elasticity.
Main Results:
- Electrophoretic velocity is dependent on particle shape in viscoelastic fluids, unlike in Newtonian fluids.
- Slenderer particle shapes (pear, peanut) exhibit enhanced electrophoretic velocity compared to spherical shapes.
- This shape dependence intensifies with increasing poly(ethylene oxide) concentration due to heightened fluid elasticity.
Conclusions:
- Fluid elasticity, rather than particle size alone, induces particle shape dependence in electrophoresis.
- The observed phenomenon offers a mechanism for label-free electrophoretic separation of particles and cells.
- Non-Newtonian microfluidic devices can leverage this effect for advanced separation applications.
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