•Tetraethoxysilane phase is compressed and restricted as a liquid core after monomers polymerize.•Hybrid microcapsules were obtained via in situ miniemulsion polymerization.•Magnetic microcapsules are obtained conveniently by adding hydrophobic Fe3O4 nanoparticles in the oil phase.Magnetic hybrid-shell microcapsules were fabricated by restricting tetraethoxysilane (TEOS) phase as a liquid core due to the phase separation via one-step miniemulsion polymerization. The inner void size of magnetic hybrid-shell microcapsules could be easily tuned by adjusting the TEOS content in the miniemulsion formulation. The magnetic hybrid-shell microcapsules were characterized by FTIR, transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The results showed that magnetic hybrid-shell microcapsules had an average size of 200–600 nm and the saturation magnetization values of the samples were 14.7 and 18.3 emu/g. The magnetic microcapsule may provide a very promising vehicle for drug delivery, catalysis, and photoelectric materials.

We describe a facile and flexible technique for fabricating Janus magnetic microcapsules via double in situ miniemulsion polymerization. Under a magnetic field, magnetic nanoparticles move to one side of the miniemulsion monomer droplets. After the monomers polymerize, an inorganic tetraethoxysilane (TEOS) phase is compressed and restricted as a liquid core due to the phase separation between TEOS and the growing polymer. After the monomers turn into a polymeric shell and the silica forms completely, the volume of the TEOS phase decreases dramatically leading to a hollow structure. Magnetic nanoparticles are chemically embedded in one side of the microcapsule shell and Janus magnetic microcapsules are fabricated efficiently and conveniently by a one-step method.

We describe a facile and flexible technique for fabricating double-shelled hybrid hollow microspheres with a controlled void size via in situ miniemulsion polymerization. After monomers polymerize the tetraethoxysilane phase is compressed and restricted as a liquid core leading to the formation of a hollow structure and silica shell. Furthermore, magnetic hollow microspheres are obtained conveniently.

Polyvinyl alcohol (PVA) micro- and nanospheres provide new options for drug delivery due to their biocompatibility, biodegradability and their tunable drug loading and release properties. PVA nanodroplets were fabricated by inverse miniemulsion process and then PVA microspheres were obtained by using glutaraldehyde (GA) as a cross-linking agent. Magnetic nanoparticles were in situ formed on the surfaces of PVA microspheres based on the classical coprecipitation procedure to fabricate magnetic PVA microspheres. The microspheres were characterized by FTIR, X-ray diffraction (XRD), transmission electron microscopy (TEM), light scattering equipment, and vibrating-sample magnetometry (VSM), respectively. The experimental results clearly show that PVA droplets were solidified after the cross-linking reactions to form PVA microspheres. The magnetic PVA microspheres are about 80–200 nm with magnetic particle of about 18 nm on the surfaces. The biocompatible and biodegradable nature of PVA indicates that this system seems to be a very promising vehicle for hydrophilic drug delivery.PVA nanodroplets are obtained by inverse miniemulsion process and then solidified using glutaraldehyde (GA) as a cross-linking agent. Magnetic nanoparticles are in situ synthesized on the surfaces of PVA microspheres based on the classical coprecipitation procedure to fabricate magnetic PVA microspheres.Highlights► PVA nanodroplets are prepared via inverse miniemulsion process. ► PVA microspheres are obtained using glutaraldehyde as a cross-linking agent. ► Magnetic nanoparticles are in situ formed to fabricate magnetic PVA microspheres.

This paper reports a rapid and facile method of preparing free-standing colloidal crystals from monodisperse charged polystyrene (PS) microspheres. Mixed solvents (ethanol/water) were used as the dispersion medium in the self-assembly process of colloidal crystals. By a simple “floating self-assembly” method, PS microspheres floated on the surface of liquid and self-assembled into large area of three-dimensional (3D) ordered colloidal crystals within 15 min. Then epichlorohydrin was added in as a cross-linking agent to strengthen the colloidal-crystal film. After cross-linking reactions between the microspheres, the obtained colloidal-crystal film was free-standing and could be easily transferred to other substrates. Using tetrabutyl titanate as a titania precursor, 3D porous TiO2 materials with rodlike skeletal structure were fabricated from the prepared free-standing colloidal crystal. This work provides a facile method to fabricate free-standing colloidal-crystal film, which can be used as an ideal template for the preparation of porous materials.Graphical abstractOptical photographs of colloidal multi-layers from PS microspheres of different size: (a) 140 nm, (b) 216 nm, and (c) 282 nm. (d and e) show the free-standing colloidal films prepared from 158 nm microspheres.Research highlights► Colloidal crystals are fabricated via “floating self-assembly” method within 15 min. ► Free-standing colloidal-crystal film is obtained using epichlorohydrin as cross-linking agent. ► Free-standing colloidal crystals could be used as ideal templates for 3DOM materials.

Amphiphilic poly (lactic acid, PLA)-polyurethane (PULA) containing carboxylic groups was synthesized via step polycondensation. Anionic PULA micelles were prepared by microphase separation process and the critical micelle concentration (CMC) was calculated by determining the solubilizing power to naphthalene in PULA aqueous solution through UV-visible spectrophotometer. By choosing gliclazide as a testing drug, the degradation properties of drug-loaded micelles were investigated by spectrofluorometer method. The results showed that the CMC value was far below that of low molecular weight surfactants. Compared with the blank micelles, the average particle size of micelles with drug entrapped increased and its distribution became narrower. The degradation of PULA micelles could be controlled by adjusting pH value in micellar system. The carboxylic groups in the micelles had great influences on the drug-releasing rate, which was much lower than that of micelles derived from PEG–PLA block copolymer.