Recent Advances in Catanionic Mixtures

Abstract

Most surfactant mixtures display synergistic physicochemical properties, which have led to their extensive application in various technologies. Aqueous mixtures of two oppositely charged surfactants, so-called catanionic surfactant mixtures, exhibit the strongest synergistic effect, which is manifested as high surface activity, enhanced adsorption and a low critical aggregation concentration. In addition, catanionic systems display rich phase behavior and a range of nano and microstructures, including small spherical micelles, rod-like micelles as well as open and closed bilayers (vesicles). The spontaneous formation of catanionic vesicles is of special interest due to their various applications in nanotechnology and pharmaceutical formulations. In this chapter, the properties of catanionic mixtures of amphiphilic molecules with advantageous properties are discussed. Since numerous papers dealing with catanionic mixtures of monomeric surfactants already exist, the aim of this chapter is to summarize recent progress in mixtures of structurally different surfactants. At the end of the chapter, special emphasis is placed on applications of catanionic mixtures.

Biocompatible Catanionic Vesicles from Arginine-Based Surfactants: A New Strategy to Tune the Antimicrobial Activity and Cytotoxicity of Vesicular Systems

“…For the catanionic mixtures prepared with single-chain surfactants (LM), the cac decreased from 4.7 and 1.6 mM for the pure compounds to 0.3 and 0.4 mM for 8.2LM and 2.8LM, respectively. The 5.5LM mixture precipitated at an equimolar concentration, a frequent occurrence in equimolecular mixtures of oppositely charged surfactants due to the complete neutralization of ionic charges [ 15 ]. The decrease in cac was higher for the C3L mixtures, dropping from 3 and 9 mM for the pure compounds to 0.08–0.3 for the catanionic mixtures, and even more so for the C3S mixtures.…”

“…In most studies on catanionic mixtures, alkyl ammonium bromide surfactants are chosen as the positively charged components [ 15 ]. Recently, due to their enhanced properties, catanionic mixtures containing gemini surfactants such as bis-quaternary ammonium salts have also been used.…”

Soft Nanoonions: A Dynamic Overview onto Catanionic Vesicles Temperature-Driven Transition

“…Indeed, a double-tailed zwitterionic behavior is responsible for the pairing of the anionic-cationic surfactants. Therefore, the above-mentioned zwitterionic double-chained structure self-generates by the association of oppositely charged single-tailed surfactants [1][2][3]. Nowadays, these vesicular systems are of increasing interest as they are widely employed in the pharmaceutical/biotechnological field (e.g., targeted gene therapy, medicated syrups, eye drop products, etc.)…”

Pseudo-zwitterionic microvesicles for sustained urea release

“…14 Cationic or anionic amphiphiles form micelles in aqueous solution above critical micelle concentration (CMC), however, their equimolar catanionic mixture predominently exists in vesicles. 15 These (pseudo-zwitterionic) vesicles are composed of bilayers formed by ion-pairs of oppositely charged surfactants. They are more stable than micelles or lipid aggregates due to the absence of head-group repulsions.…”

“…18,19 Recently, the potential of catanionic system has been evaluated for drug-delivery and related applications. 8,15,20 However, their candidature for sustained release of fertilizers has never been explored. Keeping in view the benefits associated with the use of catanionic mixture as a delivery system, the present work intends to investigate the potential of pseudo-zwitterionic system based on equimolar sodium dodecyl sulfate and hexadecyltrimethylammonium bromide (HTAB) for sustained-urea release.…”