The Formation of OTDD Network Structure in PS‐ bb ‐PI‐ bb ‐PDMS Triblock Terpolymer

摘要

> Ordered tricontinuous double‐diamond (OTDD) morphology is formed in cast film of polystyrene‐ block ‐polyisoprene‐ block ‐polydimethylsiloxane triblock terpolymer from toluene solution, though OTDD structure is not an equilibrium structure in triblock terpolymer. The small‐angle X‐ray scattering study revealed the following two‐step microphase separation during solvent cast: In the early stage of the cast process, polydimethylsiloxane (PDMS) segregates from the other two components and self‐assembles into hexagonally packed PDMS cylinders in polystyrene (PS)/polyisoprene (PI) matrix with being PS and PI in disordered state. Subsequently, the second‐step microphase separation is induced between PS and PI as toluene evaporates gradually during solvent‐cast process. Since the kinetic barrier of transition from cylinder to gyroid is higher than that from cylinder to OTDD, the metastable OTDD is formed.