Physicochemical Analysis of Mixed Micelles of a Viologen Surfactant: Extended to Water-in-Oil (w/o) Microemulsion and Cucurbit[8]uril-Assisted Vesicle Formation

Abstract

A systematic study of the self-assembly process of a viologen-containing surfactant in aqueous medium is reported. Dodecyl-ethyl-viologendibromide (DDEV) is mixed in different proportions with dodecyltrimethylammonium bromide (DTAB), and the physicochemical properties of micellization are evaluated in order to find a suitable combination which does not interfere with the micellar properties of DTAB but introduces the characteristic properties of viologen. In this process, 1% doping of DDEV with DTAB was found to be the most appropriate, as negligible changes were observed in the physicochemical behavior of this system with respect to that of pure DTAB. The 1% DDEV-doped DTAB mixed micellar system showed the characteristic two-step reduction process for the viologen units at the interface as revealed by CV experiments. 1% mixing of DDEV with DTAB also allowed us to prepare stable w/o microemulsions containing viologen units at the interface which is otherwise unattainable with pure viologen surfactants. The charge-transfer capability of the viologen unit to the electron-rich 2,6-dihydroxynaphthalene (DHN) moiety inside the macrocyclic host, cucurbit[8]uril (CB[8]) is also evaluated for this system, and surprisingly even at this very low concentration, the ternary complex of DDEV-DHN@CB[8] transformed the micellar assembly to uniform vesicles. All of these properties have been further extended to other tetraalkylammonium surfactants, and similar effects were observed.

Reversible deformation–formation of a multistimuli responsive vesicle by a supramolecular peptide amphiphile

“…The DLS distribution of the DHN treated solution showed a slight decrease in the particle size ( Figure S7 of the ESI). [37][38][39][40] The solution binding constant for DHN to MV@CB [8] complex, as reported by Scherman et al, was found to be higher than that of Azo-AA (K a = (5.9 ± 0.5) × 10 5 M -1 ). All these information lead to the conclusion that the vesicle structure remained intact even after the addition of DHN.…”

“…32 Importantly, the ternary complex, Trp-HDEV@CB [8] transformed the solutions into spherical nano-aggregates as seen from the FESEM and TEM images ( Figure 2). [37][38][39][40][41] In order to confirm the formation of vesicles, we have entrapped a water soluble dye, CF, inside these nano-aggregates and followed the release of the encapsulated dye through enhancement of fluorescence intensity. [37][38][39][40][41] In order to confirm the formation of vesicles, we have entrapped a water soluble dye, CF, inside these nano-aggregates and followed the release of the encapsulated dye through enhancement of fluorescence intensity.…”

“…Since the molecules are adhered together through multiple weak interactions, appropriate stimulus can be used to dis-assemble them easily. 38,39 Scheme 1. CB [8] is a macrocyclic synthetic host capable of accommodating two guests inside its hydrophobic cavity simultaneously and hence acts as a "supramolecular handcuff".…”

Supramolecular Chemistry of Cucurbiturils: Tuning Cooperativity with Multiple Noncovalent Interactions from Positive to Negative

“…On account of their high affinities, CB[n]-mediated host-guest interactions are of great interest in the field of supramolecular chemistry and chemical biology. [25][26][27][28][29][30][31][32] While the ability to exhibit multiple non-covalent interactions, CB [8]-mediated heteroternary and homoternary complexes have been exploited in the construction of supramolecular polymers, 33-36 supramolecular hydrogels, [37][38] supra-amphiphiles [39][40] and other supramolecular functional self-assembled systems [41][42][43][44][45][46] .…”

The mixing behaviour of anionic and nonionic surfactant blends in aqueous environment correlates in fatty acid ester medium

“…[15,16]. In spite of extensive studies of micelles and RMs using similar set of surfactant(s) [17][18][19][20], a proper understanding at a molecular level is still in demand. In the presence study, we have investigated the effect of mixing of two surfactants (anionic and nonionic) on the physicochemical characterization of the mixed micellar solutions as well as the corresponding RMs in order to optimize and design their properties.…”