Self-assembly of Anacardic Acid Derived Cation-modified Montmorillonite into ′Arthropodal′ Branched Nanofibers

Functionalization-Induced Self-Assembly of Polystyrene/Kaolinite in Situ Nanocomposites into Giant Vesicles

We report a facile functionalization strategy for fabrication of giant, inorganic-polymer hybrid vesicles by controlled aminosilyl/vinylsilyl functionalization (AS/VS) of the aluminol layer in kaolinite (Kaol) by intercalation and subsequent polymerization of styrene with the in situ polystyrene clay nanocomposite (PCN), followed by self-assembly in solvents. The synergistic effect of the AS/VS ratio on functionalization-assisted intercalation of Kaol was established in 1:3AS/VS-Kaol by the greater extent of formation of higher interlayer spacing corresponding to 1.12 nm compared to 1:1AS/VS-Kaol. As the AS/VS ratio was increased, the PCN synthesized showed an increase in molecular weight attributed to higher vinyl functionalization of Kaol. The PCN, 1:3AS/VS-Kaol/PS, showed self-assembly in tetrahydrofuran at 2.5 mg mL-1 into giant vesicles of 2-6 μm diameter with a wall thickness of 300-400 nm. This result is attributed to the functionalization-induced molecular mass-directed bilayer assembly of the delaminated, Janus-type, modified Kaol in a polar aprotic solvent by end-to-end hydrogen bonding involving terminal -OH groups along the wall and -NH2 groups laterally and further stabilized by the π-π interactions of the phenyl moiety along the periphery. Rhodamine-loaded vesicles showed a controlled release in buffer solutions of pH 7.0 and 9.0, attributed to the amino group-assisted pore formation. In a buffer solution of pH 4.0, rapid release of the dye was observed because of the collapse of the vesicle directed by protonation of the amino group. This study forms the first report on a novel method for the synthesis of rigid vesicles by functionalization-induced self-assembly of Kaol-based in situ PCN for possible applications in the cost-effective controlled delivery of drugs or cosmetics for topical applications.

Self-assembly of oleylamine modified nano-fibrillated cellulose from areca husk fibers into giant vesicles

Nanotechnology involving cellulosic substrates has generated a great attention owing to their exceptional physical and chemical properties. Self-assembled nanostructures obtained from carbohydrate polymers are of interest in the biomedical field for the biocompatibility and non-toxic nature. In the present study modification of nano-fibrillated cellulose (NFC) synthesised from the husk fibers of Areca catechu nuts (AHF) was studied by controlled regio-selective amidation with oleylamine (OA) and characterized. The modified system (MNFC) with more than 66% OA content showed self-assembly into unilamellar vesicles of 2-5μm diameters with a wall thickness of 300-600nm in tetrahydrofuran (THF) at 2.5mgmL^-1. This result is attributed to the folding of MNFC into bilayers driven by long cis-unsaturated aliphatic chains in polar aprotic solvents stabilized by hydrogen bonded interactions within the fibrils. These giant vesicles formed can have applications in storage and delivery of drugs in topical applications.