Surface structure of ultrathin copolymer films of ferroelectric vinylidene fluoride (70%) with trifluoroethylene (30%) on graphite
Surface structure of ultrathin copolymer films of ferroelectric vinylidene fluoride (70%) with trifluoroethylene (30%) on graphite
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DOI：
10.1103/physrevb.70.155411
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发表时间：
2004-10
影响因子：
3.7
通讯作者：
L. Cai;H. Qu;Chenxi Lu;S. Ducharme;P. Dowben;Jiandi Zhang
中科院分区：
文献类型：
--
作者：
L. Cai;H. Qu;Chenxi Lu;S. Ducharme;P. Dowben;Jiandi Zhang
用扫描隧道显微镜（STM）研究了偏氟乙烯（70%）与三氟乙烯（30%）[P（VDF-TrFE）]共聚物在石墨上形成的铁电结晶膜的结构和局部结构畸变。通过高分辨率STM观察到在$\mathrm {C}\mathrm{C}$键中具有围绕聚合物链轴的旋转的准螺旋扭曲，表明应变共聚物膜的表面弛豫。这种弛豫行为似乎与所观察到的局部偶极旋转伴随着局部极化的反转与偏置STM尖端有关。根据观测结果提出了一个结构模型。
The structure and local structural distortions, through the polarization manipulation, of crystalline films of ferroelectric vinylidene fluoride (70%) with trifluoroethylene (30%) [P(VDF-TrFE)] copolymer on graphite were studied by scanning tunneling microscopy (STM). A quasispiral twist in $\mathrm{C}\mathrm{C}$ bonds with rotations about the polymer chain axis was observed by high-resolution STM, indicating a surface relaxation of the strained copolymer films. Such a relaxation behavior appears to be linked to the observed local dipole rotations accompanied by the reversal of the local polarization with biasing the STM tip. A structure model is proposed based upon the observations.