Electrospray induced ferroelectricity in poly(vinylidene fluoride) thin films
Electrospray induced ferroelectricity in poly(vinylidene fluoride) thin films
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DOI：
10.1039/c0jm01265c
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发表时间：
2010-09
影响因子：
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通讯作者：
I. Rietveld;K. Kobayashi;Takuya Honjo;K. Ishida;Hirofumi Yamada;K. Matsushige
中科院分区：
文献类型：
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作者：
I. Rietveld;K. Kobayashi;Takuya Honjo;K. Ishida;Hirofumi Yamada;K. Matsushige
铁电聚合物薄膜在柔性和轻量化电子设备中的应用非常有趣。在铁电聚合物中，聚偏氟乙烯（PVDF）具有最高的理论铁电矩。然而，开发含有显著铁电矩的PVDF薄膜的单步生产方法是困难的，因为需要同时满足大量的加工要求：薄膜沉积，铁电β相形成和偶极子排列。尽管如此，电喷雾沉积似乎是一种很有前途的方法。用红外吸收法研究了电喷涂膜的结构，用原子力显微镜法和宏观I-V测量法测定了膜的铁电性。用0.05 wt% PVDF溶液在DMF中制备的薄膜仅由嵌入在非晶相中的小铁电β相晶体组成。由于电喷雾中存在离子电流，在电喷雾沉积过程中β相偶极子的形成和排列是逐步发生的。此外，如果非铁电α-相最初存在于薄膜中，则随着喷涂时间的延长逐渐消失。因此，电喷雾可以根据喷射电流和喷射时间提供具有铁电性水平的PVDF薄膜。
Ferroelectric polymer thin films are interesting for applications in flexible and lightweight electronic equipment. Among the ferroelectric polymers, poly(vinylidene fluoride) (PVDF) possesses the highest theoretical ferroelectric moment. However, development of single-step production methods of PVDF thin films containing a significant ferroelectric moment is difficult, due to the large number of processing requirements that need to be fulfilled simultaneously: film deposition, ferroelectric β-phase formation, and dipole alignment. Nonetheless, electrospray deposition appears to be a promising method. The structure of electrospray-deposited films has been studied by infrared absorption and the ferroelectricity of the films has been determined by AFM methods and by macroscopic I–V measurements. Films prepared with solutions of 0.05 wt% PVDF in DMF consist solely of small ferroelectric β-phase crystallites embedded in amorphous phase. The formation and alignment of β-phase dipoles occur progressively during electrospray deposition because of the ion current present in electrospray. Moreover, if the non-ferroelectric α-phase is initially present in the film, it disappears progressively as a function of spray time. Thus, electrospray can provide PVDF thin films with a level of ferroelectricity depending on the spray current and on the spray time.