Hybrid Surfactant Systems with Inorganic Constituents

Abstract

Surfactants are molecules of enormous scientific and technological importance, which are widely used as detergents, emulsifiers, and for the preparation of diverse nanostructures. Their fascinating ability to form self-organized structures, such as micelles or liquid crystals, originate from their amphiphilic architecture-a polar head group linked to a hydrophobic chain. While almost all known surfactants are organic, a new family of surfactants is now emerging, which combines amphiphilic properties with the advanced functionality of transition-metal building blocks, for example, redox or catalytic activity and magnetism. These hybrid surfactants exhibit novel self-organization features because of the unique size and electronic properties of the metal-containing entities.

Inorganic–Organic Hybrid Surfactant Crystals: Structural Aspects and Functions

“…POM-surfactant hybrids can allow fine tuning of the structure and function by changing the combination of POM anion and surfactant cation. Several properties have been investigated as amphiphilic [98][99][100], magnetic [101], catalytic [102], electrochemical [103], and photoluminescent [103][104][105][106] materials.…”

“…The layered POM-surfactant hybrids with two-dimensional anisotropy have been assembled as liquid crystals [105], thin films [101,103,106], and mesostructured solids [100,102,[107][108][109][110][111][112]. However, most of them are materials with atomically ill-ordered structure.…”

Redox-active organic–inorganic hybrid polyoxometalate micelles

“…12 In this covalent approach, the inorganic POMs are functionalised with organic groups, such as long aliphatic alkyl chains, to form organicinorganic hybrid molecules which can assemble to form micellar, vesicular and liquid crystal-like states. Polarz, Song, Cronin, Liu and their co-workers have pioneered the field of covalently functionalized polyoxometalate-surfactants, and shed light on their complex architectures and self-assembly, [13][14][15][16][17][18][19][20][21][22][23][24] _ENREF_15 however, relatively little is known about the physicochemical properties of the nanoscale hybrid assemblies, and in particular the translation of POM functionality across the scales, from molecular to supramolecular and bulk.…”

Magnetic surfactants

“…Since then many different complexing agent-metal ion combinations have been introduced [70][71][72][73][74][75]. The difference between these compounds and the ionic surfactants mentioned above is simply that they were coordinated with two or more separate sites rather by simple electrostatic interactions.…”