Authors: Tuncer Çaykara Melike Demiray Olgun Güven
Publish Date: 2005/09/15
Volume: 284, Issue: 3, Pages: 258-265
Abstract
A series of thermosensitive hydrogels were prepared from N3dimethylaminopropylmethacrylamide DMAPMA monomer by using 116–178 m/m NNmethylenebisacrylamide MBAAm as the crosslinker and comonomer in water A kinetic study of the absorption determined the transport mechanism The diffusion coefficients of these hydrogels were calculated for the Fickian mechanism It was shown that the swelling behavior of the PDMAPMAcoMBAAm hydrogels can be controlled by changing the amount of MBAAm The swelling equilibrium of the PDMAPMAcoMBAAm hydrogels was also investigated as a function of temperature in aqueous solutions of the anionic surfactant sodium dodecyl sulfate SDS and the cationic surfactant dodecyltrimethylammonium bromide DTAB In pure water irrespective of the amount of MBAAm the PDMAPMAcoMBAAm hydrogels showed a discontinuous phase transition between 30 and 40 °C However the transition changed from discontinuous to continuous with the addition of surfactants this is ascribed to the conversion of nonionic PDMAPMAcoMBAAm hydrogel into polyelectrolyte hydrogels due to binding of surfactants through the hydrophobic interaction Additionally the amount of free SDS and DTAB ions was measured at different temperatures by a conductometric method it was found that the electric conductivity of the PDMAPMAcoMBAAm – surfactant systems depended strongly on both the type and concentration of surfactant solutions
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