Spontaneous wormlike micelles formed in a single-tailed zwitterionic surface-active ionic liquid aqueous solutionElectronic supplementary information (ESI) available: Characterization and additional results including DSC, surface tension, DLS, and FF-TEM, POM, DFT and HNMR spectra. See DOI: 10.1039/c7sm00304h

Wormlike micelles were successfully fabricated by the self-assembly of a single-tailed zwitterionic surface-active ionic liquid (SAIL), 3-(1-hexadecyl-3-imidazolio) propanesulfonate β-naphthalene sulfonate (C 16 IPS-Nsa), in aqueous solutions without any additives. With increasing zwitterionic SAIL concentration, spontaneous transition from micelles to wormlike micelles and then a hexagonal phase occurs. Interestingly, the wormlike micelles are closed, stretched and directionally arranged, which was rarely found in previous research studies. This kind of wormlike micelle is useful to serve as novel soft template in the synthesis of functional materials. 1 H NMR illustrated that the introduced π-π stacking and hydrophobic interactions originated from the hydrophobic aromatic counterions are responsible for the structural transformation. Density functional theory (DFT) simulated the optimum configuration of C 16 IPS-Nsa and calculated the interaction energy of C 16 IPS-Nsa-H 2 O is 39.6 kJ mol −1 . This work paves the way for regulating the self-assembly structures of amphiphiles through changing specific weak interactions. Spontaneous transition from micelles to wormlike micelles and then a hexagonal phase was achieved by single-tailed zwitterionic SAILs without any additives.