Permeability of Soft Particles at Electrical Fields
Journal of Nanoscience and Nanotechnology
|October 28, 2015
Summary
The charge on microgel particles controls their permeability, with ionized networks acting as permeable spheres. Local viscosity changes, influenced by salt and hydrated ions, explain these permeability shifts.
Area of Science:
- Soft matter physics
- Polymer science
- Physical chemistry
Background:
- Microgel particles are widely used in various applications.
- Understanding their behavior under external stimuli is crucial.
- The influence of charge on microgel permeability is not fully understood.
Purpose of the Study:
- To investigate the effect of particle charge on microgel permeability.
- To elucidate the mechanisms behind charge-induced permeability changes.
- To explore the role of local viscosity and ion-network interactions.
Main Methods:
- Electrophoresis experiments on pH-ionizable poly(N-isopropylacrylamide-co-acrylic acid) (pNIPAM-AA) microgels.
- Nuclear Magnetic Resonance (NMR) spectroscopy for independent confirmation.
- Analysis of salt-dependent viscosity variations.
Main Results:
- Ionized microgel networks exhibit permeable sphere behavior.
- Non-ionized microgel networks behave as non-permeable.
- A salt-dependent local viscosity, attributed to hydrated counterions, explains the observed permeability changes.
Conclusions:
- The ionic nature of the microgel network is a key determinant of its permeability.
- Hydrated counterions significantly influence local viscosity and particle permeability.
- NMR spectroscopy validates the findings from electrophoresis experiments.
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