Theoretical study on the phase behavior of amphiphilic triblock copolymers PEO-PPO-PEO in aqueous solutions

The effects of the molecular weight on the phase behavior of amphiphilic triblock copolymers PEO-PPO-PEO in aqueous solutions were studied by using the self-consistent mean-field theory formulated in reciprocal space. The theoretical study predicted the stability ranges of various lyotropic liquid crystalline phases. By systematically varying the molecular weight, phase diagrams of several PEO-PPO-PEO triblock copolymers in water were constructed. Moreover, the effects of the block copolymer molecular weight on the volume fraction profiles for the components in the self-assembled structures were investigated. It was found that an increased molecular weight increased the segregation among the components at the given temperature. Good agreements were found between experimental results and theory.