Phase and rheological behaviour of viscoelastic wormlike micellar solutions formed in mixed nonionic surfactant systems
Acharya, Durga P.; Khalid Hossain, Md.; Jin-Feng, Jin-Feng; Sakai, Takaya; Kunieda, Hironobu; Acharya Durga P.; Graduate School of Environment and Information Sciences, Yokohama National University; Khalid Hossain Md.; Graduate School of Environment and Information Sciences, Yokohama National University; Jin-Feng ; IIQAB, Consejo Superior de Investigaciones Cientificas (CSIS); Sakai Takaya; Materials Development Research Laboratories, Kao Corporation; Kunieda Hironobu; Graduate School of Environment and Information Sciences, Yokohama National University
Журнал:
Physical Chemistry Chemical Physics
Дата:
2004
Аннотация:
The phase and rheological behaviour of mixed nonionic surfactant system â polyoxyethylene cholesteryl ether (ChEO15)â alkanoyl-N-methylethanolamide (NMEA-n)â water was studied at 25â °C. With addition of NMEA to the ChEO15â water binary system, a micellar (Wm)â lamellar (Lα) phase transformation takes place at low ChEO15 concentration. Within the Wm phase region of the ChEO15â NMEA-12â water system, there exists a high-viscosity region consisting of a viscoelastic micellar solution of entangled wormlike micelles, as suggested by rheological measurements. These solutions obey the Maxwell model of a viscoelastic fluid. Substitution of NMEA-12 by its analogue with a longer hydrophobe (NMEA-16) in the mixed surfactant system increases the extent of micellar growth, however, a phase separation occurs before a highly viscoelastic micellar system is formed. This may be attributed to the increase in packing constraints in the lipophilic core of the micelle that favours unidimensional growth.
375.3Кб