Observation of Double Gyroid and Hexagonally Perforated Lamellar Phases in ABCBA Pentablock Terpolymers

Three symmetric linear pentablock terpolymers, poly(tert-butyl acrylate-b-styrene-b-ethylene oxide-b-styrene-b-tert-butyl acrylate) (TzSyOxSyTz), with similar lengths of PS (S) and PtBA (T) blocks on the two sides but various lengths of the PEO (O) block in the middle, namely, T95S62O46S62T95, T105S60O90S60T105, and T107S65O136S65T107, were synthesized from their corresponding parent triblock copolymers poly(styrene-b-ethylene oxide-b-styrene)...