计算机辅助设计三聚氰胺分子印迹聚合物

Studies on Melamine Molecularly Imprinted Polymers by Computers Aided Design

借助密度泛函理论(DFT)长程校正方法,以三聚氰胺(MAM)为印迹分子,甲基丙烯酸(MAA)为功能单体,分别以二甲基丙烯酸乙二醇酯(EGDMA)、三羟甲基丙烷三甲基丙烯酸酯(TRIM)及二乙烯苯(DVB)为交联剂,以乙腈(ACN)、甲醇(MT)、乙醇(EA)、甲苯(TL)、四氢呋喃(THF)及二甲基亚砜(DMSO)为溶剂,模拟了MAM与MAA单体分子印迹聚合物(MIPs)自组装体系的构型,讨论了MAM与MAA的成键作用位点,及其稳定复合物的印迹反应比例及印迹作用机理,依据结合能(ΔE)优化了交联剂和溶剂,并借助分子中原子理论(AIM)揭示了MAM与MAA印迹作用的本质.计算结果表明,MAM印迹分子三嗪环上的N与胺基上H均通过氢键与MAA单体进行印迹聚合反应,且在印迹反应比例为1∶6,以TL为溶剂时形成的MAMMAA有序复合物结合能最低,构型最稳定;与TRIM及EGDMA交联剂相比,DVB与MAM结合能最低,更适宜作为MAM-MAA印迹聚合物的交联剂.本研究为MAM-MIPs合成时印迹比例、交联剂及溶剂的选择提供了理论依据.

The density functional theory（ DFT） and long range corrections method are applied to simulate the self-assembly system of the molecularly imprinted polymers（ MAM-MIPs）. Melamine（ MAM） was taken as the template molecule and methacrylic acid（ MAA） was taken as the monomer,the ethylene glycol dimethacrylate（ EGDMA）,trimethacrylate（ TRIM） and divinylbenzene（ DVB） were taken as the cross-linking agents. And the acetonitrile（ ACN）,methanol（ MT）,ethanol（ EA）,toluene（ TL）,tetrahydrofuran（ THF） and dimethylsulfoxide（ DMSO） were taken as the solvents. The geometry optimization,the bonding situation of MAM and MAA,the imprinted ratio of the stable complex and the reaction mechanism were discussed. The optimizations of the cross-linking agents and solvents were according to the bond energy（ ΔE）. The nature of the imprinting effect was also studied by the atoms in molecules（ AIM） theory. The results indicate that the N atom on the three triazine rings as well as the H atom on the amine of MAM and MAA monomer have interaction to form imprinted polymers via the hydrogen bonds. The molar ratio of 1 ∶ 6 had the strongest stability. DVB was the best cross-linking agent of MAM-MIPs in comparison with TRIM and EGDMA. The study can provide a theoretical reference for the optimization of the imprinting ratio and the choice of crosslinking agent and solvent on MAM-MIPs.