基于酪氨酸的Bola型表面活性剂的合成及胶束化行为研究

Synthesis and Micellization of a novel bolaamphiphile derived from tyrosine

摘要:

本研究利用L-酪氨酸和l,12-二氨基十二烷合成了bola型表面活性剂l,12-二酪氨酸基十二烷基二胺盐(DADT)，用 1H NMR对其结构进行表征。通过电导率法和等温滴定量热法结合三维荧光光谱法考察了DADT在水溶液的自聚集行为。结果表明，其临界胶束浓度(cmc)为0.16 mmol/L 左右，随温度升高，cmc值逐渐增大；随离子强度增强，cmc值明显降低。同时，DADT具有荧光信号，在浓度低于0.18 mmol/L时，荧光强度随浓度的增大而增大，当浓度增大到0.18 mmol/L时，由于发生自聚集导致荧光猝灭，从而荧光强度随浓度的增大而减小。研究还发现，DADT分子自身荧光猝灭浓度与其临界胶束浓度一致，为研究其胶束化行为提供了一种简便方法。

Abstract:

l,12-tyrosine diaminododecane(DADT) was synthesized by L-Tyrosine and 1,12-dodecanediamine and the structure of DADT was characterized by 1H NMR. The self-aggregation behavior of DADT in water was determined by conductivity, isothermal titration calorimetry and fluorescence spectroscopy. The critical micelle concentration (cmc) of DADT is ca.0.16 mmol/L. The cmc value displays a weak trend of increase along with the increase of temperature and it decreases remarkably with the ionic strength increase. Meanwhile, the fluorescence intensity increases with the concentration of DADT when its concentration is lower than 0.18 mmol/L. When its concentration reaches 0.18 mmol/L , DADT monomers can self-aggregate into micelles so that the fluorescence intensity decreases accordingly. Meanwhile, it is found that the concentration of self-quenching of DADT is consistent with its critical micelle concentration which provides a convenient way for the study of the micellization behavior of bolaamphiphiles.