title: Role of ion-dipole interactions in nucleation of gamma poly(vinylidene fluoride) in the presence of graphene oxide during melt crystallization.
abstract: The crystallization behavior and crystalline structure of poly(vinylidene fluororide) (PVDF) in the presence of graphene oxide (GO) platelets were investigated using time-resolved Fourier transformation infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), as well as differential scanning calorimetry (DSC). It is shown that GO platelets induce the formation of γ phase when crystallizing from solution, but only α phase forms from melt crystallization. The crystallization kinetics of α phase is promoted due to heterogeneous nucleation ability of GO, which is probably originated from a weak π-dipole interaction between GO and PVDF. Intriguingly, after introduction of strong ion-dipole interactions between GO and PVDF by addition of an ionic surfactant (cetyltrimethylammonium bromide, CTAB), a significant amount of γ crystals are obtained during isothermal melt crystallization. Time-resolved FTIR results further provide a detailed evolution of the γ phase formation, and there are two distinct stages during the melt crystallization in the PVDF/GO composites in the presence of CTAB, i.e., a simultaneous growth of γ and α phases in the first stage, and a solid α to γ transition in the second stage. These results may provide a facile routine to manipulate the crystalline structure in PVDF/GO composites, and thus to gain desirable properties.
authors.affiliation: College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, Sichuan, People's Republic of China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.forename: Jia-Zhuang
authors.initials: JZ
authors.lastname: Xu
authors.forename: Lei
authors.initials: L
authors.lastname: Zhu
authors.forename: Gan-Ji
authors.initials: GJ
authors.lastname: Zhong
authors.forename: Zhong-Ming
authors.initials: ZM
authors.lastname: Li