Highly Asymmetric Phase Diagram of a Poly(1,2‐octylene oxide)–Poly(ethylene oxide) Diblock Copolymer System Comprising a Brush‐Like Poly(1,2‐octylene oxide) Block

Abstract

The phase diagram of a series of poly(1,2-octylene oxide)-poly(ethylene oxide) (POO-PEO) diblock copolymers is determined by small-angle X-ray scattering. The Flory-Huggins interaction parameter was measured by small-angle neutron scattering. The phase diagram is highly asymmetric due to large conformational asymmetry that results from the hexyl side chains in the POO block. Non-lamellar phases (hexagonal and gyroid) are observed near f(PEO) = 0.5, and the lamellar phase is observed for f(PEO) ≥ 0.5.