Photo-induced dynamic association of coumarin pendants within amphiphilic random copolymer micelles
Photo-induced dynamic association of coumarin pendants within amphiphilic random copolymer micelles
复制标题
两亲性无规共聚物胶束内香豆素悬垂物的光诱导动态缔合
DOI：
10.1007/s00396-014-3474-7
复制
发表时间：
2015-03-01
影响因子：
2.4
通讯作者：
Jiang, Jinqiang
中科院分区：
文献类型：
--
作者：
Chang, Huan;Liu, Yan;Jiang, Jinqiang
设计了一种水溶性两亲性香豆素侧基无规共聚物P（DMA-co-VBC），研究了香豆素侧基在聚合物胶束中的光诱导动态缔合.采用吸收光谱、发射光谱、溶液透过率、动态光散射（DLS）和原子力显微镜（AFM）等方法进行研究。结果表明，P（DMA-co-VBC）在水溶液中能形成聚合物胶束。聚合物胶束在不同强度的320 nm光照射下的光二聚度（PD）随时间的变化呈现饱和现象，最大光二聚度值与光强无关，而香豆素二聚体的最大光裂解度随254 nm光照射强度的增加而下降。此外，在光二聚过程中，在445 nm（I-2）处明显出现了一个显著的发射带，而在385 nm（I-1）处发射带消失，并且聚合物水溶液在320和254 nm光的交替照射下的时间依赖性I-2/I-1比率显示出作为照射周期的函数的波浪式增加，表明在可逆的光二聚循环过程中香豆素侧基在聚合物胶束内的波浪形紧密性。
The water-soluble amphiphilic random copolymer of P(DMA-co-VBC) with coumarin pendants has been designed to investigate the photo-induced dynamic association of coumarin pendants within polymer micelles in aqueous solution. Methods of absorption and emission spectra, solution transmittance, dynamic light scattering (DLS), and atomic force microscope (AFM) were applied. It was found that P(DMA-co-VBC) can form polymer micelles in aqueous solution. The time-dependent photo-dimerization degree (PD) of polymer micelles upon different intensity irradiations of 320 nm light showed saturating behaviors with an intensity-independent value of the maximum photo-dimerization extent, while the maximum photo-cleavage extent of coumarin dimers declined with the increasing intensity of 254 nm irradiation at used conditions. Furthermore, a significant emission band at 445 nm (I-2) evidently emerged as against the disappearance of emission band at 385 nm (I-1) during the photo-dimerization, and the time-dependent I-2/I-1 ratios of polymer aqueous solution upon alternative irradiations of 320 and 254 nm light showed a wave-like increase as a function of irradiation cycles, indicating a wavy closeness of coumarin pendants within polymer micelles during the reversible photo-dimerization cycles.