pH-triggered aggregation behavior of hybrid chitosan assemblies with controlled density distribution of gold nanoparticles

The structure and stability of colloidal gold-chitosan assemblies is assessed as a function of charge density and conformation of chitosan chains in a wide range of the polycation concentration and on a broad time-scale. The preservation of the initial optical properties of gold nanoparticles is ach...

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Bibliographic Details
Published in:Colloid and polymer science 2019-03, Vol.297 (3), p.339-350
Main Authors: Lopatina, L. I., Tsarkova, L. A.
Format: Article
Language:English
Subjects:
Assemblies
Characterization and Evaluation of Materials
Charge density
Charge reversal
Chemistry
Chemistry and Materials Science
Chitosan
Complex Fluids and Microfluidics
Control stability
Density distribution
Food Science
Gold
Invited Article
Molecular conformation
Nanoparticles
Nanotechnology and Microengineering
Optical properties
Phase separation
Physical Chemistry
Polyelectrolytes
Polymer Sciences
Polymers
Sedimentation
Soft and Granular Matter
Stability analysis
Structural stability
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Summary:The structure and stability of colloidal gold-chitosan assemblies is assessed as a function of charge density and conformation of chitosan chains in a wide range of the polycation concentration and on a broad time-scale. The preservation of the initial optical properties of gold nanoparticles is achieved at a high chitosan concentration as a result of the charge reversal by adsorbed highly charged polymer or as a result of the formation of bulky layers of weakly charge polymer, preventing the coagulation of the particles. In the latter case, slow sedimentation of macroscopically large red flocs was attributed to the increased segment-segment attraction between segregated chitosan chains, confirmed by TEM analysis. At the regime of low chitosan concentration, the best long-term stability was observed in the case of an intermediate charge density on the polymer. The surface-enhanced phase separation of the weak polyelectrolyte was confirmed by liquid-cell SFM measurements. Graphical abstract
ISSN:0303-402X
1435-1536
DOI:10.1007/s00396-018-4413-9