Photoinduced Opposite Diffusion of Nematic and Isotropic Monomers during Patterned Photopolymerization
Photoinduced Opposite Diffusion of Nematic and Isotropic Monomers during Patterned Photopolymerization
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DOI：
10.1021/cm970305l
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发表时间：
1998
影响因子：
8.6
通讯作者：
C. F. Nostrum;R. Nolte;D. Broer;T. Fuhrman;J. Wendorff
中科院分区：
文献类型：
--
作者：
C. F. Nostrum;R. Nolte;D. Broer;T. Fuhrman;J. Wendorff
用光刻和全息技术对含有液晶双丙烯酸酯和各向同性单丙烯酸酯的光反应混合物的薄膜进行了UV曝光，得到了薄膜中的空间光强分布。在紫外线强度最大的位置，活性更强的双丙烯酸酯被优先消耗，导致这种单体优先扩散到这些区域。单丙烯酸酯相反地扩散到强度最小的位置，这取决于聚合物比例和液晶转变温度，最终导致从向列相到各向同性相的相变。用这种方法制备的全息光栅由于光学取向和各向同性材料的线条的交替而表现出高的衍射效率。用简单的聚合扩散模型成功地模拟了扩散过程，并结合荧光显微镜进行了荧光标记实验验证。
Films containing a photoreactive mixture of a liquid-crystalline diacrylate and an isotropic monoacrylate were UV exposed by means of lithographic and holographic techniques, resulting in a spatial intensity distribution in the films. The favored depletion of the more reactive diacrylate at sites with maximum UV intensity results in preferred diffusion of this monomer to these areas. The monoacrylate oppositely diffuses to the sites with minimum intensity which, depending on polymer ratios and liquid-crystalline transition temperatures, eventually leads to a phase transition from the nematic to the isotropic phase. In this way holographic gratings were prepared exhibiting high diffraction efficiencies due to the alternation of lines of optically oriented and of isotropic materials. The diffusion process was successfully simulated by a simple polymerization and diffusion model and was verified by fluorescent labeling experiments in combination with fluorescence microscopy.