摘要
以六氯环三磷腈和4,4'-二羟基二苯砜为单体,通过一步沉淀聚合制备了环交联型聚磷腈荧光纳米纤维(PZS-NF),对其化学结构、形貌、热稳定性及荧光特性进行了表征;进一步以PZS-NF为荧光化学传感器,研究了其检测液相中苦味酸(PA)的性能,并探讨了检测机理.结果表明:PZS-NF的平均直径为80 nm,高度交联的有机-无机杂化结构赋予了其优异的热稳定性;纳米纤维在369 nm紫外光的激发下,在433 nm具有显著的荧光特性,对液相中的PA表现出了高灵敏、高效和高选择性的荧光猝灭响应;优异的检测性能缘于PZS-NF结构中具有大量富电子的氮原子,通过酸碱相互作用将PA分子富集到纳米纤维表面,从而有效促进了PZSNF与PA之间形成非荧光基态配合物,同时有利于PZS-NF向PA发生激发态能量转移.
The cyclomatrix-type polyphosphazene fluorescent nanofibers（PZS-NFs）were prepared by one-step precipitation polymerization of hexachlorocyclotriphosphazene and 4,4＇-sulfonyldiphenol with trimethylamine as acid-accepter and a mixture of toluene and acetone （8 ： 1 by volume） as solvent. The chemical structure, morphology,thermal stability, and fluorescent property of PZS-NFs, were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, thermal gravity analysis, and fluorescence spectroscopy, respectively. Then PZS-NFs were served as a fluorescent chemical sensor for the detection of PA in solution phase by a spectrofluorometric titration method using a spectrofluorometer. The selective detection performance was investigated, and the corresponding detection mechanism was also discussed. The results showed that the mean diameter of the nanofibers was 80 nm. The highly cross-linked and organic-inorganic hybrid structure endowed the nanofibers with excellent thermal stability. The initial thermal decomposition temperature was as high as 520 ℃ in nitrogen atmosphere. The nanofibers exhibited an intrinsically fluorescent emission at 433 nm when excited at 369 nm,and showed the fluorescence quenching response towards PA with high sensitivity,efficiency, and selectivity over a number of other analytes including 2, 4, 6-trinitrotoluene, 2, 4-dinitrotoluene, 1, 3-dinitrobenzene, 4-nitrophenol, nitrobenzene, 4-benzoquinone, chlorobenzene, and nitromethane in methanol. The quenching constant and detection limit for PA were 1.81 × 10^4 M -1 and 80 μg/L,respectively. The specific recognition of PA by PZS- NFs might be attributed to the effective enrichment of PA from solution to the surface of PZS-NFs realized by the acid-base interaction between the acidic phenolic hydroxyl groups of PA molecules and the electron-rich nitrogen atoms of the cyclotriphosphazene units in PZS-NFs, facilitating the formation of a ground-state non- fluorescent complex of the nanofibers and PA as well as the excited-state energy transfer from the nanofibers to PA. Considering the simple preparation and high selectivity, PZS-NFs have a great potential to serve as a fluorescence chemical sensor for the detection of PA in practice.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2015年第12期1477-1485,共9页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号21404049)
中央高校基本科研业务费专项资金(项目号JUSRP11420)资助项目
关键词
聚磷腈
纳米纤维
荧光
苦味酸
选择性检测
Polyphosphazene, Nanofibers, Fluorescence, Picric acid, Selective detection
