(180r) Effect of Charge and Fluctuation of Vesicle Membranes on the Oligomerization of Aniline

Polyaniline is a material applied to sensor elements and secondary batteries, and conductivity is required. In the enzyme polymerization reaction, it is a problem that not only the conductive emeraldine salt but also the insulating pernigranilin salt is formed.

In recent years, the soft template effect of soft interfaces such as vesicles has been studied as a method for selectively polymerizing emeraldine salts. Vesicles are closed system composed of lipid bilayer membranes. In the soft template effect, it is said that micelles and vesicles provide a local environment with different pH and charge in bulk. However, how this effect induces emeraldine salt has not been elucidated.

Therefore, in this study, kinetic analysis and fluctuation analysis of vesicle membrane in the enzyme polymerization reaction of aniline were performed using giant vesicles (GVs; particle diameter of 1 μm or more) which can be observed microscopically. Next, the interaction between the enzyme (protein) and the membrane was examined, and the soft template effect by the soft interface in the enzyme polymerization reaction was evaluated.

As a result of the experiment, an emeraldine salt of an aniline oligomer was formed using negatively charged surfactant vesicles. In this case, the enzyme was oriented inside the vesicle membrane, and the membrane was found to be large fluctuation.Since the conductive emeraldine salt is positively charged, it is considered that the intermediate emeraldine salt is captured at the strongly negative vesicle interface.