支化侧链偶氮聚电解质的光致二向色性和表面起伏光栅

PHOTO-INDUCED DICHROISM AND SURFACE RELIEF GRATINGS OF TWO NOVEL BRANCHED SIDE-CHAIN AZO POLYELECTROLYTES

通过后重氮偶合的方法合成了两种含支化侧链偶氮苯生色团的聚电解质PBANT AC和PBACT AC .用红外光谱、氢核磁共振谱、紫外 可见光光谱、热分析和元素分析等手段对聚合物的结构和性能进行了表征 .在 4 88nm的偏振Ar+ 激光的照射下 ,聚合物薄膜中的偶氮苯生色团可发生光致取向 ,取向有序度分别为 0 12和 0 0 9.在干涉偏振激光束的照射下 ,两种聚合物旋涂膜表面均形成了规则的正弦表面起伏光栅 ,其起伏深度分别为 4 0nm和 80nm左右 .用氦氖激光实时检测 ,测定了两种旋涂膜表面起伏光栅的一级衍射效率随光照时间的变化关系 .

Novel polyelectrolytes (PBANT-AC and PBACT-AC) functionalized with branched side-chains containing electron donor-acceptor type azo chromophores have been synthesized through a post- polymerization azo-coupling reaction route and characterized by H-1-NMR, FTIR and UV-Vis spectroscopy. The degree of functionalization ( DF) of PBANT-AC and PBACT-AC were 17% measured by elemental analysis. The degree of polymerization and its distribution were determined by GPC to be X-n = 588 with a polydispersion index 1.3. Glass transition temperatures of PBANT-AC and PBACT-AC were estimated from DSC thermogram to be 139degreesC and 159degreesC, respectively. Dichroism was optically induced in the spin-coated films of the two polymers under the irradiation of a polarized Ar+ laser beam, at 488 nm. The resulting dichroism was detected from UV-Vis spectra, which exhibited a long-term stability at room temperature. The orientational order parameters obtained were 0. 12 and 0.09 for the PBANT-AC and the PBACT-AC films. Surface relief gratings were optically inscribed upon exposure to an interference pattern of Ar+ laser beams at modest intensities. The surface modulations were about 45 nm and 80 mn for PBANT-AC and PBACT-AC films estimated from their AFM data.