Synthesis And Interfacial Properties Of Quaternary Ammonium Cationic Surface Monomer Bearing Piperazine Group

Novel monovalent quaternary ammonium surface monomer 1-undecylmethacrylate-1-bromide-1,4-dimethylpiperazine (PQⅠ) and Divalent quaternary ammonium surface monomer 1-undecylmethacrylatedibromide-1,4-dimethylpiperazine(PQⅡ) successfully synthesized using methacryloyl chloride, 11-bromoundecan-1-ol, 1,4-dimethylpiperazine and methy bromide as raw materials under the suitable conditions.The products (PQⅠand PQⅡ) were characterized by FTIR, 1H-NMR spectroscopy, 13C-NMR spectroscopy and elemental microanalysis, respectively.The results show that PQⅠand PQⅡcould be easily synthesized through three steps reaction; including one acryloyl chloridation and two alkanylations under the suitable conditions. Additionally, the critical micelle concentration (CMC) and surface tension were also measured. In pure water at 25℃, CMC of PQⅠand PQⅡare 44.6mmol/L and 67.3mmol/L, respectively, and the corresponding surface tensionγcmc are 40.95mN/m and 37.9mN/m.The solubility of PQⅠand PQⅡare determined by UV spectroscopy. Aggregation numbers of mcelle (Nagg) of PQⅠand PQⅡare determined by steady state fluorescene probe method, in which prene is used as fluorescene probe and benzophenone as quencher. Meanwhile the effects of PQⅠand PQⅡconcentration and additional salt concenttation on aggregation numbers are also investigated. The experiment results show that the solubility of PQⅠand PQⅡare large in pure water, while its ability of reducting water surface tension is weak, which suggests that PQⅠand PQⅡhave poor surface activity. Compared with the common surfactants possessily the similar structure, PQⅠand PQⅡhave low CMC value and Krafft Points. Aggregation numbers of PQⅠand PQⅡmicelle increas with the increasing PQⅠand PQⅡconcentration. In the presence of additional salt, at constant temperature, Nagg firstly shows slowly-increasing with sodium salt concentration until the concentration of additional salt is equal to the critical concentration C*, Nagg increases sharply.