a 天津科技大学 材料科学与化学工程学院 天津 300457;
b 中国石油石油化工研究院 合成树脂加工应用研究室 北京 100195
Preparation and Properties of Crown Ethers Containing Amphiphilic Copolymer Nano-aggregates
Zhang Yu-Jiana,b, Xie Binb, Jiang Taoa
a Tianjin University of Science and Technology, Materials Science and Chemical Engineering Institute, Tianjin 300457, China;
b Petrochemical Research Institute of PetroChina, Synthetic Resins and Processing Applications Lab, Beijing 100195, China
In this paper, an amphiphilic copolymer poly(2,2'-(1,10-diaza-crown-6-1,10-diyl)diethyl 5-((adenin-9-yl)- methyl)isophthalate) (PDCAI) was designed and synthesized by simulating the chemical structure of DNA. We observed its self-organized morphology in the aqueous solution and in potassium solution with scanning electron microscopy (SEM), amphiphilic copolymer PDCAI spontaneously aggregated into strip aggregates in aqueous solution, and which could change into a rod, nanotube or helical rod aggregates in KNO3 solution. In addition, the molecular recognition between copolymer PDCAI and thymine substrate has been studied via FT-IR, and it is found that C2=O of thymine had recognized with PDCAI through complementary nucleobases in aqueous solution, the C2=O stretching band of thymine at 1737 cm-1 shifted to 1710 cm-1 after recognition, however, the band of the C4=O of thymine did not change at 1677 cm-1. Meanwhile we attempted to regulate the molecular recognition of copolymer PDCAI with thymine substrate with K+, we surprisingly found that hydrogen bonding occurs on C4=O of thymine when it recognized with PDCAI in KNO3 solution, the C4=O stretching band of thymine at 1677 cm-1 shifted to 1671 cm-1, however, the band of the C2=O of thymine did not change at 1737 cm-1 after recognition. It proves that the recognizing conformation of thymine re-organized during identification process due to the transition of aggregation form of PDCAI. And we further confirmed and studied the hydrogen bond formation and fracture process by variable temperature FT-IR, which formed at room temperature gradually broke while temperature rising from 25℃ up to 115℃, when temperature was above 115℃, hydrogen bonds broke completely, thymine and PDCAI return to their pre-recognition state. The formations of hydrogen bonds between adenine in the polymer and thymine substrate in nanospheres could enhance their interaction and loading capacity. The results have reference value for research of molecular characteristics of polymer which spontaneously formed spiral, preparation of helical polymer, and nucleic acid imitation drug carriers and its function regulation.