Aqueous polysaccharide associations mediated by beta-cyclodextrin polymers.
Macromolecular assemblies were elaborated by mixing in water hydrophobically modified dextrans (MDC(n)) and beta-cyclodextrin polymers (pbetaCD) interacting by inclusion complexation between the hydrophobic moieties of MDCn and the beta-cyclodextrin cavities of pbetaCD. Dextrans have been modified by grafting alkyl groups (C(n)) of varying chain lengths (n = 8-16) and grafting ratio (3-6 mol%). Different pbetaCD polymers were synthesized by polycondensation of beta-cyclodextrin and epichlorohydrin. The polymer-polymer interactions have been studied by fluorimetry, isothermal titration microcalorimetry, phase diagrams, and viscosimetry. The viscoelastic properties of the temporary networks (in the semidilute range) have been studied by rheology. The interaction mechanisms between the MDCn and pbetaCD can be understood taking into account the strength of the interaction between the alkyl group and the beta-cyclodextrin cavity (mainly controlled by the alkyl chain length), the density of junctions between the chains (depending on the alkyl grafting density and the pbetaCD molecular weight), and additional cooperative effect (arising for high alkyl grafting density).
Wintgens
Véronique
V
Systèmes Polymères Complexes, ICMPE, UMR 7182, 2 Rue Henry Dunant, 94320 Thiais, France.
Daoud-Mahammed
Samia
S
Gref
Ruxandra
R
Bouteiller
Laurent
L
Amiel
Catherine
C
D000478:Alkylation; D057927:Hydrophobic and Hydrophilic Interactions; D011134:Polysaccharides / Q000737:chemistry*; D014783:Viscosity; D014867:Water; D047392:beta-Cyclodextrins / Q000737:chemistry*
D011134:Polysaccharides; D047392:beta-Cyclodextrins; D014867:Water