Highly cross-linked narrow or monodisperse poly(divinylbenzene) (PDVB) microspheres were prepared by distillation-precipitation polymerization as a novel polymerization technique in acetonitrile with 2,2′-azobis(2-methylpropionitrile) (AIBN) as initiator. The polymeric microspheres were formed simultaneously through a precipitation polymerization manner during the distillation of acetonitrile off the reaction system. Narrow or monodisperse particles with spherical shape and smooth surface were prepared with diameters between 1.10 and 3.41 µm without any stabilizers. The particle size and size distribution depended on the reaction conditions. The maximum particle size of 2.14 µm with size distribution index of 1.058 was attained at cross-linking degree of 64%, and the size distribution became narrower with increasing cross-linking degree. The particle sizes increased with increasing monomer and initiator concentration. A series of polymer particles with diameter between 1.99 and 3.41 µm were obtained by multi-semibatch mode with successive introduction of a mixture of the designed amount of AIBN and divinylbenzene containing 80% divinylbenzene (DVB80) in acetonitrile into the distillationprecipitation polymerization, and the size distribution index was kept around 1.02. Furthermore, the conversion increased from 31% for the first aliquot to 76% for the sixth aliquot. All of the resulting microspheres were characterized with SEM.

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Water retention is a pervasive issue in agriculture and industry. Inspired by the water‐storage mechanisms in plant cells, three kinds of polymeric microcapsules (PMCs) with carboxylic acid, sulfonic acid, and pyridyl groups are prepared using distillation–precipitation polymerization. The size of the lumen of the PMCs may govern the static water uptake by holding water molecules in a free‐water state, and the functional groups in the shell of PMCs may manipulate dynamic water release by holding water molecules in a bound‐water state, thus yielding PMCs with high and tunable water‐retention properties. Incorporation of PMCs into composite membranes gives rise to dramatically enhanced water‐retention properties and proton‐transfer pathway, and consequently increased proton conductivity by up to one order of magnitude over the control polymer membrane, under low relative humidity of 20%. This study may offer a facile and generic strategy to design and prepare a variety of materials with superior water‐retention properties.

Design and fabrication of hierarchically structured membranes with high proton conductivity is crucial to many energy-relevant applications including proton exchange membrane fuel cell (PEMFC). Here, a series of imidazole microcapsules (IMCs) with tunable imidazole group loading, shell thickness, and lumen size are synthesized and incorporated into a sulfonated poly(ether ether ketone) (SPEEK) matrix to prepare composite membranes. The IMCs play two roles: i) Improving water retention properties of the membrane. The IMCs, similar to the vacuoles in plant cells, can render membrane a stable water environment. The lumen of the IMCs acts as a water reservoir and the shell of IMCs can manipulate water release. ii) They form anhydrous proton transfer pathways and low energy barrier pathways for proton hopping, imparting an enhanced proton transfer via either a vehicle mechanism or Grotthuss mechanism. In particular, at the relative humidity (RH) as low as 20%, the composite membrane exhibits an ultralow proton conductivity decline and the proton conductivity is one to two orders of magnitude higher than that of SPEEK control membrane. The enhanced proton conductivity affords the composite membrane an elevated peak power density from 69.5 to 104.5 mW cm − 2 in a single cell. Moreover, the application potential of the composite membrane for CO 2 capture is explored.

Alternating silica/polymer tetra- and penta-layer hybrid microspheres were first prepared via combined inorganic sol−gel reaction and distillation-precipitation polymerization. pH-responsive poly(methacrylic acid) (PMAA) hollow microspheres with asymmetric double-shells were produced after HF etching of the silica layers in the SiO2/PMAA tetra-layer microspheres with different degrees of cross-linking in the two PMAA layers. On the other hand, silica “core−double shell” hollow microspheres were obtained by calcination of the alternating silica/PMAA penta-layer microspheres. The resulting hollow polymer and silica microspheres with hierarchical structures were characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) analysis, dynamic laser scattering (DLS), and confocal laser scanning microscopy (CLSM) measurements.

Narrowly-dispersed silver@silica@poly(methacrylic acid) (Ag@SiO 2 @PMAA) core-double shell hybrid nanoparticles (NPs) were first synthesized by distillation-precipitation polymerization, using silver@silica core-shell NPs from the sol-gel reaction as templates. Selective removal of the inorganic silica inner-shell from the Ag@SiO 2 @PMAA core-double shell hybrid NPs by HF etching produces the Ag@air@PMAA hybrid nanorattles with a Ag nanocore, PMAA shell and free space in between. The Ag nanocores, Ag@SiO 2 core-shell NPs, Ag@SiO 2 @PMAA core-double shell NPs and Ag@air@PMAA hybrid nanorattles were characterized by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy and energy-dispersive X-ray (EDX) analysis. The as-synthesized Ag@air@PMAA hybrid nanorattles were explored as a nanoreactor system for confined catalytic reaction. The rate of catalytic reaction can be further regulated by controlling molecule diffusion in and out of the stimuli-responsive PMAA shell through the simple variation of environmental stimuli, such as salt (NaCl) concentration of the medium.

Nearly monodispersed silica-poly(methacrylic acid) (SiO 2-PMAA) core-shell microspheres were synthesized by distillation-precipitation polymerization from 3-(trimethoxysilyl)propylmethacrylate-silica (SiO 2-MPS) particle templates. SiO 2-PMAA-SiO 2 trilayer hybrid microspheres were subsequently prepared by coating of an outer layer of SiO 2 on the SiO 2-PMAA core-shell microspheres in a sol-gel process. pH-Responsive PMAA hollow microspheres with flexible (deformable) shells were obtained after selective removal of the inorganic SiO 2 core from the SiO 2-PMAA core-shell microspheres by HF etching. The pH-responsive properties of the PMAA hollow microspheres were investigated by dynamic laser scattering (DLS). On the other hand, concentric and rigid hollow silica microspheres were prepared by selective removal of the PMAA interlayer from the SiO 2-PMAA-SiO 2 trilayer hybrid microspheres during calcination. The hybrid composite microspheres, pH-sensitive hollow microspheres, and concentric hollow silica microspheres were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray (EDX) analysis.

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