荧光双重敏感响应型水溶聚合物的合成及其发光性能研究

SYNTHESIS AND LUMINESCENCE PROPERTIE OF BIFUNCTIONAL WATER-SOLUBLE LUMINESCENCE POLYMER MATERIALS

将丙烯酰氯与荧光素反应,合成出丙烯酸酯单体3-丙烯酰氧基荧光素(Ac-Flu),然后采用自由基溶液聚合法将Ac-Flu与丙烯酰胺(AM)共聚,制备得到含有荧光素生色团的水溶性荧光共聚物poly(Ac-Flu-co-AM).合成单体Ac-Flu和共聚物poly(Ac-Flu-co-AM)采用核磁(NMR),质谱(HR-MS),红外光谱(FTIR),示差扫描量热法(DSC),可见紫外分光光度仪(UV-Vis)等方法进行了结构表征,同时采用荧光光谱对共聚物poly(Ac-Flu-co-AM)的荧光极其荧光对温度和pH敏感响应性进行了测定研究.结果表明,poly(Ac-Flu-co-AM)的水溶液和薄膜在520 nm附近均具有较强的荧光发射.其中,水溶液荧光强度在0～60℃范围内随着温度的升高呈线性下降,表现出较好的温度敏感响应性质.同时,水溶液荧光强度在pH=4～10范围内随着碱性的增强而升高,表现出较好的pH敏感响应性质.

An unsaturated monomer bearing luminescence group,acryloyloxyfluorescein（Ac-Flu） was synthesized from fluorescein and acryloyl chloride in the presence of triethylamine in dry dichloromethane（CH2Cl2） at room temperature.The synthesized Ac-Flu was identified by IR,MS and 1H-NMR spectra.Copolymer of Ac-Flu and acrylamide was synthesized with thermal initiator,and poly（Ac-Flu-co-AM） was characterized by the method of IR,UV-Vis and DSC.The photophysical behaviors of the copolymer were explored by recording the fluorescence spectra in solution and film.In addition,the pH and temperature dependence of fluorescence of the water-soluble poly（Ac-Flu-co-AM） was investigated in detail.The results showed that the relative fluorescence intensity of poly（Ac-Flu-co-AM） at near 520 nm had an excellent linear response to temperature in the range of 0~60℃,the linear regression equation of the calibration graph was FI=740.06-3.0683T,（FI was relative fluorescence intensity,T was temperature）,with a correlation coefficient of linear regression of 0.9974.Moreover,the fluorescence intensity increased continuously from low pH to high pH from 4.0 to 10.0 after the addition of HCl or NaOH,which resulted from the fact that the predominance of tautomeric forms of Ac-Flu changed at different medium.This investigation may provide a convenient way to prepare multifunctional macromolecule biomaterial bearing fluorescein to probe pH and temperature in biological system.