Silva Bruno F B, Marques Eduardo F
Centro de Investigação em Química, Department of Chemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
J Colloid Interface Sci. 2005 Oct 1;290(1):267-74. doi: 10.1016/j.jcis.2005.04.012.
Catanionic surfactants formed by the pairing of two ionic amphiphilic chains of opposite charge are now recognized as an important class of amphiphiles. Many aspects of their phase behavior have yet to be explored. In this work, two homologous series of catanionic surfactants were synthesized, based on the cationic headgroups trimethylammonium and pyridinium. Within each series, the headgroup and chain length of the cationic counterpart remains constant while for the anionic counterpart the headgroup is varied, while its alkyl chain length is also kept constant. Thus, one can directly monitor the influence of headgroup chemistry on the thermal behavior of these compounds. Differential scanning calorimetry (DSC) and polarizing light microscopy show that these compounds bear a rich and often complex thermotropic behavior, with the headgroup chemistry in some instances having a rather dramatic influence on phase behavior. Several liquid crystalline phases appear between the solid crystalline phase and the isotropic liquid phase. A qualitative correlation between the observed thermotropic behavior and the chemical nature of headgroup is presented.
由两个带相反电荷的离子型两亲链配对形成的阴阳离子表面活性剂，如今被公认为一类重要的两亲物。其相行为的许多方面尚待探索。在这项工作中，基于阳离子头基三甲基铵和吡啶鎓合成了两个同系系列的阴阳离子表面活性剂。在每个系列中，阳离子对应物的头基和链长保持恒定，而对于阴离子对应物，头基有所变化，同时其烷基链长也保持恒定。因此，可以直接监测头基化学对这些化合物热行为的影响。差示扫描量热法（DSC）和偏光显微镜表明，这些化合物具有丰富且往往复杂的热致行为，在某些情况下，头基化学对相行为有相当显著的影响。在固晶相和各向同性液相之间出现了几个液晶相。给出了观察到的热致行为与头基化学性质之间的定性关联。
