화학공학소재연구정보센터
Journal of Colloid and Interface Science, Vol.180, No.2, 421-427, 1996
Interaction of Nonionic Block Copolymeric (Poloxamer) Surfactants with Poly (Acrylic-Acid), Studied by Photon-Correlation Spectroscopy
The interaction between certain hydrophilic pluronic (poloxamer) surfactants and a poly (acrylic acid) has been investigated, Both the PPO and the PEO groups of the surfactants, and the -COOH groups and aliphatic side chains of the PAA molecule, were found to be crucial in this interaction to form complexes. At pH 2 and with a low poloxamer:PPLA molar ratio, maximum interaction was observed, giving rise to large-sized complexes that were unstable but possessing bioadhesive properties. At the same pH but with higher poloxamer:PAA molar ratio, the complexes became smaller in size and more stable and were used to prepare stable w/o/w emulsions. A further increase in the poloxamer:PAA molar ratio or increase in the pH causes a further decrease in particle size with eventual nonformation of complexes. Interaction and stability studies of the complexes were done using photon correlation spectroscopy, The overall interaction appears to be a combination of hydrophobic interaction and hydrogen bonding. This has given rise to a unique ratio which we have called the [oxyphobic]/[oxyphilic] ratio or OOR. The interaction was found to depend on the molar ratio between poloxamer surfactants and PPA; the [O](total)/[-COOH] ratio; the size of the PPO hydrophobe, and the pH of the reaction mixture, pH measurement studies of these mixtures also gave similar results.