Preparation of wormlike PNIPAM microcontainers with magnetic nanoparticle inclusions

Wormlike poly(N-isopropylacrylamide) (PNIPAM) microcontainers with magnetic nanoparticle inclusions were prepared. First, wormlike iron oxide/SiO2 nanostructures were prepared based on one-dimensional chainlike self-assembly of magnetic nanoparticles followed by a sol-gel process of tetraethyl orthosilicate on the surface of the assemblies. Then, the wormlike iron oxide/SiO2 nanostructures were grafted with linear copolymer of N-isopropylacrylamide (NIPAM) and γ-methacryloxypropyltrimethoxysilane (MPS). PNIPAM shell was fabricated on the P(NIPAM-co-MPS)-modified wormlike iron oxide/SiO2 nanostructures by precipitation polymerization of NIPAM and N,N′-methylenebisacrylamide (MBA). At last, wormlike PNIPAM microcontainers with magnetic nanoparticle inclusions were obtained by removing the middle silica layer with NaOH. The microcontainers have potential applications in drug delivery system, protective shield for bioactive materials, etc.

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► The microcontainers were prepared based on one-dimensional self-assembly of magnetic nanoparticles.
► The microcontainers possess wormlike shape, thermosensitive shell and magnetic nanoparticle inclusions.
► For fabricating PNIPAM shell on silica surface, the silica surface was modified with linear P(NIPAM-co-MPS) chains.