Imaging of Two-Dimensional Distribution of Molecular Orientation in Poly(ethylene oxide) Spherulite Using IR Spectrum and Birefringence
Imaging of Two-Dimensional Distribution of Molecular Orientation in Poly(ethylene oxide) Spherulite Using IR Spectrum and Birefringence
复制标题
DOI：
10.1021/ma3010372
复制
发表时间：
2012-10-23
期刊：
影响因子：
5.5
通讯作者：
Hashimoto, Toshimasa
中科院分区：
文献类型：
--
作者：
Hikima, Yuta;Morikawa, Junko;Hashimoto, Toshimasa
与光学双折射成像相比，分子链取向的二维定量成像与化学FT-IR成像一起提出。用傅里叶变换红外四偏振成像法研究了聚氧化乙烯（PEO）球晶的分子链取向。利用线性偏振器在四个不同角度下测量的FT-IR吸光度计算取向函数的大小和取向轴的方位角。利用电控变椭圆检偏器和圆偏振器测量的透射光强，计算了折射率椭球中的延迟和慢轴。尽管空间分辨率相差6倍，但FT-IR成像确定的方位角图像检测到了分子链取向的变化，给出了与球晶界面双折射确定的慢轴相似的方位角线轮廓。从矢量表示的比较中可以直观地确认分子链的取向轴方向与折射率椭球的慢轴方向在每个点处的良好对应。采用四偏振红外成像方法，可以直观地显示聚合物共混物球晶中各组分分子链取向的差异。
The two-dimensional quantitative imaging of molecular chain orientation is presented together with a chemical FT-IR imaging, in comparison with the optical birefringence imaging. The molecular chain orientation of the spherulite of poly(ethylene oxide) (PEO) is visualized using the four polarizations method of FT-IR imaging. The magnitude of orientation function and the azimuth angle of orientation axis are calculated with the FT-IR absorbance measured with a linear polarizer settled at four different angles. Retardation and the slow axis in a refractive index ellipsoid are calculated using transmission intensity measured with an electrical-controlled variable elliptical analyzer and a circular polarizer. In spite of the 6 times difference of the spatial resolution, the azimuth angle image determined from FT-IR imaging detects the change of molecular chain orientation, giving the similar line profiles of azimuth angle to that of slow axis determined from birefringence on the spherulite interface. A good correspondence in the direction of orientation axis of the molecular chain with the slow axis of a refractive index ellipsoid at each point is confirmed visually from the comparison of vector representation. The FT-IR imaging with four polarizations method enables to visualize the difference of molecular chain orientation of each component of the polymer blend spherulite.