Skip to Main content Skip to Navigation
Theses

Structures of electrostatic complexes between a polyelectrolyte of variable rigidity and nanoparticles of controlled size

Abstract : Electrostatic complexation process involving polyelectrolyte and nanoparticles of opposite charge are receiving an increasing interest in view of their implications in numerous domains. In this thesis, we are particularly interested in the role of ratio Lp/R on the formation of complexes. To realize the variation of this parameter, we have chosen five model systems by the combination of four polyelectrolytes of different rigidity and three oppositely charged nanoparticles of different sizes, including the positively charged AuNPs synthesized by ourselves. For each system, we have in the first place studied the macroscopic behaviors of complexes formed at different concentration ratio of PEL and NPs, which were recorded in the phase diagrams. Then, the structures of so formed complexes were studied by a combination of cryo-TEM, small-angle neutron, X-ray, and light scattering (size, fractal dimension Df). We have in particular revealed for Lp/R ≈1 the formation of well-defined single-strand nanorods and also of randomly branched complexes (Df between 1.5 and 3) respectively in the two monophasic domains (excess of nanoparticles or of PEL chains). Besides the ratio Lp/R, the salt effect was also studied by comparing salt-free system with the one in presence of additional salt, and we proved that the addition of salt can screen the repulsive charges of complexes which results in rapid phase separation and more compact complex structure. Moreover, we have observed unexpectedly the formation of AuNPs nanoparticles- Hyaluronan chains metacrystals.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-02668618
Contributor : Francois Boue <>
Submitted on : Sunday, May 31, 2020 - 1:13:44 PM
Last modification on : Monday, October 19, 2020 - 11:06:43 AM

File

Shi_2013_LLB.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-02668618, version 1

Citation

Li Shi. Structures of electrostatic complexes between a polyelectrolyte of variable rigidity and nanoparticles of controlled size. Soft Condensed Matter [cond-mat.soft]. Université Denis Diderot-PARIS VII École Doctorale : Matière condensée et interfaces, 2013. English. ⟨tel-02668618⟩

Share

Metrics

Record views

50

Files downloads

76