Phase Diagram of Poly(ethylene oxide) and Poly(propylene oxide) Triblock Copolymers in Aqueous Solutions

The phase behavior of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) triblock copolymers in aqueous solutions is studied by using a self-consistent-field theory. The spectral method is extended to polymer models with internal degrees of freedom. Phase diagrams of PEO−PPO−PEO and PPO−PEO−PPO triblock copolymers in water are constructed in the concentration−temperature space. A variety of lyotropic liquid crystalline phases is found. The effects of temperature, copolymer concentration, the block (EO/PO) ratio and the chain architecture are investigated. Good agreements were found between experimental results and theory.