Reverse‐Vesicle Formation of Organic–Inorganic Polyoxometalate‐Containing Hybrid Surfactants with Tunable Sizes

Abstract

The formation of reverse-vesicular structures of the polyoxometalate-containing hybrid surfactants [nBu(4)N](3)[MnMo(6)O(18){(OCH(2))(3)-CNHCO(CH(2))(n-2)CH(3)}(2)] (Mn-Anderson-C(n), n=6, 16) in nonpolar medium was achieved by titrating toluene into Mn-Anderson-C(n)/acetonitrile (MeCN) solution. Stepwise change of the solvent polarity induces self-association of the hydrophilic Mn-Anderson cluster on the hybrid amphiphiles. The reverse-vesicle formation was characterized by laser light scattering and further confirmed by transmission electron microscopy techniques, and the vesicle sizes increase with increasing toluene contents. The assembly process was accelerated at an elevated temperature. The length of the alkyl tails on the hybrid surfactants has a minor effect on the vesicle sizes, because the strong attraction between the polyoxometalate clusters is more dominant in the reverse-vesicle formation.

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.…”

Synthetic cellularity based on non-lipid micro-compartments and protocell models

“…Assembly is driven by a decrease in total free energy associated with placement of the particles specifically at the liquid/liquid interface [13], and produces stabilized water or oil droplets that are dispersed in an oil or water continuous phase, respectively. Since the seminal paper by Weitz et al in 2002 [14 ], a wide range of colloidosomes have been prepared using inorganic particles, such as silica [15 ,16], clays [17], CaCO 3 [18], graphene oxide [19], TiO 2 [20], Fe 3 O 4 [21], cerium oxide [22], gold particles [23], metal organic frameworks [24] and polyoxometalateorganic hybrid particles [25]. In most cases, the colloidosomes are several tens of micrometres in diameter, and consist of a monolayer of closely packed particles in the form of a continuous, enclosed membrane.…”

Amphiphilic hybrids containing inorganic constituent: More than soap

“…This makes the vesicle formation more difficult and the self assembly process takes more time compared to classical surfactants. Nevertheless, an amphiphile possessing the latter geometry is more appropriate to self assemble in apolar solvents to form reverse aggregates [49].…”