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Polystyrene-core-silica-shell hybrid particles were synthesized by combining the self-assembly of nanoparticles and the polymer with a silica coating strategy. The core-shell hybrid particles are composed of gold-nanoparticle-decorated polystyrene (PS-AuNP) colloids as the core and silica particles as the shell. PS-AuNP colloids were generated by the self-assembly of the PS-grafted AuNPs. The silica coating improved the thermal stability and dispersibility of the AuNPs. By removing the 'free' PS of the core, hollow particles with a hydrophobic cage having a AuNP corona and an inert silica shell were obtained. Also, Fe3O4 nanoparticles were encapsulated in the core, which resulted in magnetic core-shell hybrid particles by the same strategy. These particles have potential applications in biomolecular separation and high-temperature catalysis and as nanoreactors. [ABSTRACT FROM AUTHOR]

Aromatic stacking has played a significant role in the design of discrete supramolecular systems. However, for many years, the stacking of conjugated radical cations has been considered only as a novelty due to its weakness. In recent years, it has been demonstrated that the stacking of conjugated radical cations, particularly those formed by bipyridinium or tetrathiafulvalene, can be enhanced remarkably when they are incorporated into rationally designed, preorganized frameworks or entrapped into a confined space. This Focus Review highlights the recent advance in its application as an emerging non-covalent force for the construction of various supramolecular structures. [ABSTRACT FROM AUTHOR]

Materials with Janus structures are attractive for wide applications in materials science. Although extensive efforts in the synthesis of Janus particles have been reported, the synthesis of sub-10 nm Janus nanoparticles is still challenging. Herein, the synthesis of Janus gold nanoparticles (AuNPs) based on interface-directed self-assembly is reported. Polystyrene (PS) colloidal particles with AuNPs on the surface were prepared by interface-directed self-assembly, and the colloidal particles were used as templates for the synthesis of Janus AuNPs. To prepare colloidal particles, thiol-terminated polystyrene (PS-SH) was dissolved in toluene and citrate-stabilized AuNPs were dispersed in aqueous solution. Upon mixing the two solutions, PS-SH chains were grafted to the surface of AuNPs and amphiphilic AuNPs were formed at the liquid-liquid interface. PS colloidal particles decorated with AuNPs on the surfaces were prepared by adding the emulsion to excess methanol. On the surface, AuNPs were partially embedded in the colloidal particles. The outer regions of the AuNPs were exposed to the solution and were functionalized through the grafting of atom-transfer radical polymerization (ATRP) initiator. Poly[2-(dimethamino) ethyl methacrylate] (PDMAEMA) on AuNPs were prepared by surface-initiated ATRP. After centrifugation and dissolving the colloidal particles in tetrahydrofuran (THF), Janus AuNPs with PS and PDMAEMA on two hemispheres were obtained. In acidic pH, Janus AuNPs are amphiphilic and are able to emulsify oil droplets in water; in basic pH, the Janus AuNPs are hydrophobic. In mixtures of THF/methanol at a volume ratio of 1:5, the Janus AuNPs self-assemble into bilayer structures with collapsed PS in the interiors and solvated PDMAEMA at the exteriors of the structures. [ABSTRACT FROM AUTHOR]