Altering associations in aqueous solutions of a hydrophobically modified alginate in the presence of beta-cyclodextrin monomers.
The formation of associative networks in semidilute aqueous solutions of hydrophobically modified alginate (HM-alginate) is dependent on intermolecular hydrophobic interactions. Addition of beta-cyclodextrin (beta-CD) monomers to the system provides decoupling of these associations via inclusion complex formation with the polymer hydrophobic tails. This results in a dramatic decrease in the viscoelastic response of the system and a more extended local structure of the polymer chains, as shown by small-angle neutron scattering (SANS) measurements. The zero-shear viscosity decreases about an order of magnitude when the beta-CD concentration is increased from 0 to 12 mm. The lifetime of the associative network decreases strongly with increasing levels of beta-CD addition. These findings clearly demonstrate that the hydrophobic association effect is efficiently reduced as the amount of beta-CD is increased. In the framework of drug delivery, this effect may be useful to improve the release of therapeutic molecules that can be entrapped in the polymer matrix.
Department of Physics, Institute for Energy Technology, Post Office Box 40, N-2027 Kjeller, Norway.
Céline
C
Galant
Anna-Lena
AL
Kjøniksen
Giao T M
GT
Nguyen
Kenneth D
KD
Knudsen
Bo
B
Nyström
D000464:Alginates / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D009391:Nephelometry and Turbidimetry; D033363:Neutron Diffraction / Q000379:methods; D012212:Rheology; D012996:Solutions / Q000737:chemistry; D014867:Water / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000737:chemistry*
D000464:Alginates; D012996:Solutions; D047392:beta-Cyclodextrins; D014867:Water