Objective
The aim of the present project is a systematic theoretical and experimental investigation of the role of hydrophobic and electrostatic interactions in the behaviour of hydrophobically modified (HM) associating polyelectrolytes in aqueous solutions: self-assembly, gelation, phase separation etc. The existing theoretical approaches for the description of equilibrium and rheological properties of associating uncharged polymers will be generalized for the case of hydrophobically associating polyelectrolytes.
The experimental research will concentrate on a series of newly synthesized HM polyelectrolytes with well controlled degree of hydrophobicity prepared from natural polysaccharide chitin or its deacetylated form chitosan. The pliarity of such chitin derivatives is the possibility to influence their hydrophilic/hydrophobic balance both by varying the fraction and the chain length of hydrophobic stituents and by ionization of repeat units. The effect of polymer concentration, degree of hydrophobicity (which can be varied by changing the fraction and the chain length of hydrophobic n-alkyl groups), degree of ionization, ionic strength, temperature and shear rate on the physico-chemical properties of HM polysaccharides in aqueous solution (aggregation, gelation and phase separation) will be considered. Along with traditional rheological investigation of associating polymers, a particular attention will be paid to the development of the relationships between mollar mechanism of aggregation and macroscopic associative behaviour, utilizing techniques including light scattering, nuclear magnetic resonance, fluorescent probe method, small-angle X-ray scattering, calorimetry, tensiometry etc. This will permit to better understand physico-chemical mechanisms of aggregation and gelation playing an important role in the unfolding of numerous technological processes.
Topic(s)
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38042 Grenoble
France