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Updated: Jul 10, 2026
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Molecular Entanglement and Electrospinnability of Biopolymers
Published on: September 3, 2014
Combined effect of spin speed and ionic strength on polyelectrolyte spin assembly
Pritesh A Patel1, Andrey V Dobrynin, Patrick T Mather
1Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
Langmuir : the ACS Journal of Surfaces and Colloids
|November 9, 2007
Summary
Polyelectrolyte spin assembly (PSA) of multilayers shows a nonmonotonic growth rate with ionic strength due to competing electrostatic and shear flow mechanisms. Higher spin speeds lead to uniform coatings, while unique morphologies form at higher salt concentrations.
Area of Science:
- Materials Science
- Polymer Science
- Surface Chemistry
Background:
- Polyelectrolyte spin assembly (PSA) is a sequential multilayer formation technique.
- It involves adsorbing oppositely charged polyelectrolytes from dilute solutions under spin-coating flow.
Purpose of the Study:
- To investigate the impact of solution ionic strength and spin speed on PSA multilayer buildup.
- To understand the mechanisms governing layer formation and coating morphology.
Main Methods:
- Fabrication of polyelectrolyte multilayers using PSA with poly(sodium 4-styrenesulfonate) and poly(allylamine hydrochloride).
- Systematic variation of solution ionic strength and spin speed.
- Analysis of coating growth rate, polymer surface coverage, and surface topography.
Main Results:
- Multilayer buildup exhibited a nonmonotonic dependence on salt concentration, increasing then decreasing with ionic strength.
- At low ionic strength, electrostatic interactions dominated; at high ionic strength, shear flow effects were prominent.
- Radial thickness variations observed at lower spin speeds diminished with increased speed, yielding planarized coatings.
- Distinct morphological features emerged at salt concentrations > 0.1 M, influenced by spin speed and ionic strength.
Conclusions:
- The nonmonotonic behavior is explained by competing electrostatic and shear-flow-driven mechanisms.
- Spin speed controls planarization and uniformity of the multilayer coatings.
- Ionic strength and spin speed are critical parameters for tailoring film morphology and properties in PSA.
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