【摘 要】
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Poly(vinylidene fluoride)(PVDF),a versatile crystalline polymer,has drawn increasing attention in recent years owing to its extraordinary properties,particularly excellent electrical properties such a
【机 构】
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TMSR Research Center and CAS Key Lab of Nuclear Radiation and Nuclear Energy Technology,Shanghai Ins
【出 处】
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The 11th International Symposium on Polymer Physics(PP2014)(
论文部分内容阅读
Poly(vinylidene fluoride)(PVDF),a versatile crystalline polymer,has drawn increasing attention in recent years owing to its extraordinary properties,particularly excellent electrical properties such as pizeo-,pyro-,and ferro-electricity.PVDF is also notable for its polymorphism and is often observed in at least three regular conformations; namely,the all-trans(tttt)planar zigzag β-phase,the tg+tg-(trans gauche+ trans gauche-)α and δ phases,and the tttg+tttg- Γ and ε phases.Among these phases,the polar β and γ ones are the desirable crystal forms,especially the former which has the largest spontaneous polarization(p)per unit cell and thus exhibits the highest pizeo-,pyro-,and ferroelectric activities.In this work,we systematically investigated the impact of a room temperature ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6],and the IL modified carbon nanotubes(IL-CNTs)on the crystalline structure of PVDF.It was found that such an IL has significant influence on the crystal forms of PVDF in both PVDF/IL and PVDF/IL-CNTs systems.For the melt-blended PVDF/IL and PVDF/IL-CNTs composites,IL has led to main γ crystals of PVDF 1 while IL-modified CNTs consisting of large aspect ratio enable PVDF to generate dominant β-PVDF without any nonpolar α crystals 2.It has been further found that the PVDF in the electrospun PVDF/IL composite nanofiber exhibits an extremely high content(almost 100%)of β crystals 3,in contrast to the dominance of PVDF γ crystals in bulk melt-blended PVDF/IL blends.The mechanism of the crystal form transitions of PVDF by IL and IL-CNTs has been investigated.Therefore,IL plays an intriguing role in the crystalline structure of PVDF and shows a large potential application for the modification of PVDF.
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