화학공학소재연구정보센터
Macromolecular Rapid Communications, Vol.29, No.11, 876-884, 2008
Strain-induced phase morphology in melt drawn ultrathin highly oriented block copolymer films
A strain-induced microphase morphology has been established by the melt drawing process in a high molecular weight asymmetric polystyrene-block-poly(vinyl-2-pyridine) (PS-b-P2VP) diblock copolymer. For the first time to the best knowledge of the authors, the melt drawing process has been applied to block copolymers to produce free-standing, ultrathin block copolymer films with a thickness of approximate to 100 nm. Intriguingly, during the melt drawing of the polymer a global strain-induced unidirectional order of the microphase separated needle-like domains of the block copolymer was generated. This morphology consists of a PS matrix with embedded highly oriented P2VP needle-like domains oriented parallel to the drawing direction. The needle-like morphology is explained by a simplified extended chain model of the diblock copolymer chains. Annealing of the films leads to a transition from the strain-induced needle-like morphology toward the quasi-equilibrium sphere-like morphology.