A series of hyperbranched poly(ester-amide-ether)s (H-PEAEs) were synthesized via the A2+CB3 approach by the self-transesterification of ethyl ester-amide-ethers end-capped with three hydroxyl groups and ethyl ester group at two terminals. The molecular structures were characterized with 1H NMR and FT-IR spectroscopy. The number average molecular weights were estimated by GPC analysis to possess bimodal wide distribution from 1.57 to 2.09. The strong inherent blue fluorescence was observed at 330 nm for excitation and 390 nm for emission. Moreover, the emission intensity and fluorescence quantum yield increased along with the incorporated ether chain length, as well as almost linearly with the H-PEAE concentration in an aqueous solution. For comparing the fluorescence performance, the linear poly(ester-amide-ether) (L-PEAE) and hyperbranched poly(ester-amide) (H-PEA) were synthesized. The results showed that the coexistence of ether bond and carboxyl group in the molecular chain was essential for generating the strong fluorescence. However, the compact backbone of H-PEAE would be propitious to the enhancement of fluorescence properties.
一系列超支化聚酯酰胺醚(H-
PEAE)通过A2+CB3途径,即末端带有三个羟基和两个
乙酯基团的
乙酯酰胺醚的自转酯化反应合成。分子结构通过1H NMR和FT-IR光谱进行表征。数均分子量通过
GPC分析估计,具有从1.57到2.09的双峰宽分布。在激发波长为330 nm、发射波长为390 nm时,观察到强烈的固有蓝光荧光。此外,随着引入醚链长度的增加,发射强度和荧光量子产率也增加,且在
水溶液中几乎与H-
PEAE浓度呈线性关系。为了比较荧光性能,合成了线性聚酯酰胺醚(L-
PEAE)和超支化聚酯酰胺(H-
PEA)。结果表明,分子链中醚键和羧基的共存对产生强烈荧光至关重要。然而,H-
PEAE的紧凑骨架有利于增强荧光特性。