Selectively Initiated Ship-In-A-Bottle Assembly of Yolk–Shell Nanostructures

Abstract

Yolk–shell nanostructures, or nanorattles, are created by growing metal nanoparticles exclusively inside hollow porous polymer nanocapsules. Metal ions enter the nanocapsules through size-selective nanopores. Synthesis of metal nanoparticles is initiated by an agent entrapped in nanocapsules. Tannic acid, β-cyclodextrin, and polyether dendrimer were used as sacrificial molecules for initiation and growth of gold nanoparticles. If needed, initiator molecules can be fragmented by acid hydrolysis and removed from nanocapsules. Variations in reaction conditions yield encapsulated nanoparticles with different size and shape. Further functionalization of nanorattles forms encapsulated core–shell nanoparticles.

Efficient preparation of size tunable PEGylated gold nanoparticles

“…Self-assembly of the block copolymer accelerates the coalescence of the reduced metal atoms which then grow into nanoparticles over several hours 12 . Nanocapsules with containing tannic acid synthesized by directed assembly have also been used to simultaneously synthesize and encapsulate gold nanoparticles 13 . At 60°C, the procedure took ~20 minutes 13 .…”

“…Nanocapsules with containing tannic acid synthesized by directed assembly have also been used to simultaneously synthesize and encapsulate gold nanoparticles 13 . At 60°C, the procedure took ~20 minutes 13 . Building on these results, we selfassemble polymer nanoreactors in the presence of gold chloride to simultaneously synthesize PEGstabilized gold nanoparticles.…”

One-step synthesis of “rattle-like” polymer particles via suspension polymerization

“…The number of shells is determined by the number of coating layers. 31,32 However, almost all of the above preparation methods for capsules with multiple particles involve multistep processes. 27,28 In addition, double polymersomes containing several inner polymersomes were prepared using a microfluidic conjunction approach in which the inner material was not solid particles but vesicles.…”

Size‐Selective Yolk‐Shell Nanoreactors with Nanometer‐Thin Porous Polymer Shells

“…The size of entrapped NPs can be controlled by the concentration of metal ion in the aqueous core of the vesicles and the amount of initiator in the bilayer. In another method, NPs are grown exclusively inside pre‐fabricated hollow polymer nanocapsules 8b. In the latter approach, growth of gold NPs is seeded by entrapped sacrificial initiator molecules.…”

“…In the latter approach, growth of gold NPs is seeded by entrapped sacrificial initiator molecules. The type of initiator, concentration of metal ions, and the length of the synthesis control the size of NPs 8b. Preliminary data showed high activity of such yolk‐shell Au NRs in catalyzing the reduction of 4‐nitrophenol 8b…”