Self-assembly of supra-amphiphiles building block fabricated by beta-cyclodextrin and adamantane-based ionic liquid

A new adamantane-based ionic liquid, (11-(((-adamantane-1-carbonyl)oxy)undecyl)-1-methylimidazol-3-ium bromide (AD-C(11)im), was synthesized from 1-adamantanecarboxylic acid and observed that it can aggregate into micelles in aqueous solution. A number of experiments were conducted to understand the self-assembly of supra-amphiphiles building block fabricated by beta-cyclodextrin (beta-CD) and adamantane-based ionic liquid at diverse molar ratios. Studies revealed that host-guest interaction between the adamantane group and beta-CD occurred and AD-C(11)im@1 beta-CD building block formed when same amount beta-CD was added. Then the micelles aggregates formed by AD-C(11)im only turned into spherical vesicles, which was confirmed by AFM, DLS and TEM. Besides, according to the results of AFM, it can be confirmed that the vesicles were monolayer structure. When double amount beta-CD was added, both the adamantane group and the hydrophobic chain were encapsulated by beta-CD and AD-C(11)im@2 beta-CD building block formed. Thus the aggregations changed from vesicles to net-like nanofiber, which was observed by TEM. When the beta-CD concentration increased to 40 mM, the formation of light blue hydrogel was observed during the self-assembling process of AD-C(11)im@2 beta-CD building block.