A New Type of Deaggregators, the Bolaamphiphilic DeAgrs.Observations of the Dependence of Deaggregating Ability on Aggregator Concentration and Solvent Aggregating Power

• 来源期刊: 中国化学(英文版)
• 年，卷（期）: 2002,（11）
• 页码范围: 1279-1286
• 页数: 8页
• 语种: 英文

摘要

Four new amphiphilic molecules, i. e., the bolaamphipiles ω-trimethylamino n-hexadecanoate( deAgr 16 ), n-dodecanoate (deAgr 12), n-undecanoate(deAgr 11), and n-octanoate (deAgr 8)were synthesized. Their ability as deaggregators to break up the aggregating systems of hexadecyl β-naphthoate (A16) and dodecyl β-naphthoate (A12) in dioxanewater binary solvent systems was investigated in a mumber of solvent systems and at different A16 and A12 concentrations.The results reveal that this new type of bolaamphiphilic molecules appears to be one of the most efficient deaggregators reported, which, at very low concentrations, can effectively break up the aggregating systems of highly concentrated A16and A12. It is also found that bolaamphiphiles with longer aliphatic chains possess greater deaggregatibg ability. However, when the overall overall concentrations of A16 and A12 are very low but still above their critiical aggregating concentration,thee bolaamphiphilic molecules lose their deaggregating power and tend to coaggregate with the aggregated A16 or A12molecules. The quite efficient deaggregating ability of the longchain bolaamphiphiles (deAgr 16 and deAgr 12), as compared to the short-chain deAgr 8, has been ascribed to their dynamic switch-on/switch-off behavior involving coiled-up and uncoiled conformations of their long aliphatic chains.