Morphology Transition in Brush-Linear Diblock Copolymers Derived from Asymmetric Precursor Block Copolymers
발표자
()
초록
내용
Brush-linear block copolymer is interesting class of materials exhibiting complex phase morphology with both comb-like and coil-like chain characteristics. We synthesize brush-linear block copolymers by utilizing linear diblock precursors. Compositionally asymmetric poly(pentafluorophenyl acrylate-b-styrene) (PPFPA-b-PS) linear diblock copolymer is first prepared by sequential polymerization. The PPFPA block is then reacted with amine-functionalized poly(ethylene glycol) (amine-PEG) to create PPFPA-g-PEG-b-PS brush-linear block copolymers. Domain morphologies of the brush-linear block copolymers as a function of PEG side-chain substitution are examined using small-angle X-ray scattering. As a degree of PEG side-chains increases, morphology transition is observed from spheres and cylinders with PPFPA as the minority block to an inverted cylinder now with PS as the minority block. Furthermore, the two asymmetric phases are connected by a lamellar phase with a large composition window.