title: Sequence control of phase separation and dewetting in PS/PVME blend thin films by changing molecular weight of PS.
abstract: The morphology evolution mechanism of polystyrene (PS)/poly (vinyl methyl ether) (PVME) blend thin films with different PS molecular weights (Mw) was studied. It was found that the morphology evolution was closely related to the molecular weight asymmetry between PS and PVME. In the film where Mw(PS) ≈ Mw(PVME), dewetting happened at the interface between the bottom layer and substrate after SD phase separation. While in the film where Mw(PS) >> Mw(PVME), dewetting happened at the interface between the middle PS/PVME blend layer and bottom PVME layer near the substrate prior to phase separation. The different sequences of phase separation and dewetting and different interface for dewetting occurrence were studied by regarding the competitive effects of viscoelasticity contrast between polymer components and preferential wetting between PVME and the substrate. The viscoelastic nature of the PS component played a crucial role in the sequence of phase separation and dewetting.
authors.affiliation: College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400050, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Xia
authors.affiliation: College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400050, China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Qin
authors.affiliation: College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Yajiang
authors.initials: Y
authors.lastname: Huang
authors.affiliation: College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400050, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Huang
authors.affiliation: College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, China.
authors.forename: Jianhui
authors.initials: J
authors.lastname: Xu
authors.affiliation: College of Material Science and Engineering, Chongqing University of Technology, Chongqing 400050, China.
authors.forename: Youbing
authors.initials: Y
authors.lastname: Li