Control of Nanoscale Structures of Amphiphilic Self-Assembly by Physical Factors

(1)通过改变pH可逆的胶束-囊泡转变。在油基二甲胺氧化物质子化到0.5的程度（半质子化状态）时，囊泡从长纤维胶束自发形成，并且这种变化通过改变介质的pH可逆地发生。粘弹行为从麦克斯韦型特征、长纤维状胶束缠结网络到凝胶状行为。转换是相当快的，它似乎发生在2小时内。然而，囊泡悬浮液的粘弹性恢复到大致相同的水平需要长得多的时间（约14天）。这种转变很可能不是以一种过渡的方式进行，而是以一种连续的方式进行。(2)十四烷基二甲胺氧化物（C14 DMAO）在固/液界面处的膜的结构变化。云母/溶液界面、半胶束或圆柱体在非离子状态下形成，而双层在半质子化和全质子化状态下形成。石墨/溶液界面。无论质子化程度如何，都会形成半胶束。(3)萘磺酸盐（NphS）反离子对C14 DMAO的片层和囊泡形成的影响。这一结果并非微不足道，因为大多数具有C16尾部的表面活性剂阳离子形成长纤维胶束（堆积参数p接近0.5）。在本研究中，具有C14尾部的表面活性剂阳离子形成薄片（p接近于1）。在添加NphS时，ftIII质子化物质形成片层相，并且该分离的片层相可以在高温下分散为片层滴或洋葱状。半质子化的物种形成囊泡上添加NphS和他们的电荷被逆转的NphS的结合增加。

(1) Reversible micelle - vesicle transition by changing pH.On protonation of oleyldimethylamine oxides to the degree of 0.5 (the half protonated state), vesicles are formed spontaneously from long fibrous micelles and this change occurs reversibly by changing the pH of the medium. The viscoelastic behavior changes from the Maxwell type characteristic to entangled network of long fibrous micelles to the gel like behavior. The conversion is rather fast and it seems to take place within 2 hours. It takes much longer time (about 14 days), however, for the viscoelastic properties of the vesicle suspension to recover to approximately the same level. The conversion most likely proceeds not in a transition like but in a continuous way.(2) Change of the structures of the films of tetradecyldimethylamine oxides (C14DMAO) at solid/solution interface.2-1. Mica/solution interfaces, hemimicelles or cylinders are formed at nonionic state while bilayers are formed at half- and full-protonated states.2-2. Graphite/solution interfaces. Hemimicelles are formed irrespective of the degrees of protonation.(3) Lamella and vesicle formation of C14DMAO by naphthalene sulfonate (NphS) counterions. This result is not trivial because most surfactant cations with a C16 tail form long fibrous micelles (the packing parameter p close to 0.5). In this study the surfactant cations with a C14 tail form lamella (p close to unity).3-1. The fttll-protonated species form lamella phase on addition of NphS and this separated lamella phase can be dispersed as lamella drops or onions at high temperatures.3-2. The half-protonated species form vesicles on addition of NphS and their charges are reversed as the binding of NphS increases.