| Characterization of aqueous solutions of four triblock copolymers of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(butylene oxide) containing various PPO/PBO ratios was carried out in order to examine the effects of hydrophobicity on the micellization properties and phase behaviour of the systems using a combination of surface tension measurements, rheological studies, phase diagrams and dynamic light scattering data. The EPB polymer systems undergo thermoreversible gelation and their phase behaviors show strong temperature dependence and a relatively weak dependence on concentration. Analysis of the data revealed some anomalies, most notably, the increase of cmc with temperature for the two most hydrophobic copolymer samples. The phase diagrams are complex and define prominent macroscopic turbid gel, clear gel, turbid sol, clear sol and two-phase regions. |
