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As a kind of smart material, thermoresponsive hydrogels are widely investigated and applied in many fields. Due to the limitation of the freezing temperature of the water, it is a challenge to further broaden their sol–gel transition temperature (Tgel) range, especially below 0 °C. Herein, the lower critical solution temperature type of amphiphilic ABA triblock copolymers, synthesized via two‐step reversible addition‐fragmentation chain transfer (RAFT) polymerization is demonstrated. The hydrophilic A‐block and the hydrophobic B‐block are composed of poly(N,N‐dimethylacrylamide) (PDMAA) and poly(diacetone acrylamide) (PDAAM), respectively. The degree of polymerization (DP) of both A‐block and B‐block shows a significant influence on the Tgel of triblock copolymer dispersion. By changing the length of these two blocks or physically blending these copolymers dispersions, the Tgel can be well adjusted in a temperature range from 45 to −10 °C. Moreover, When the Tgel is higher than 4 °C, the triblock copolymer coatings show a good anti‐fogging property. And when the Tgel is around or lower than the freezing temperature of the water, aqueous dispersions of the triblock copolymer have an ice recrystallization inhibition activity, resulting in the decrease of average maximum grain size (MLGS) of ice crystal. [ABSTRACT FROM AUTHOR]

Graphical abstract Schematic illustration for the synthesis of SHH-MIP particles by miniemulsion polymerization Highlights • Miniemulsion polymerization is performed to synthesize MIP particles. • The obtained MIP particles exhibit single hole hollow structure. • MIP show fast adsorption kinetics with the t 1/2 of 4.35 min. • MIP display excellent binding capacities and accurate recognition specificity. Abstract The structural design on the molecularly imprinted polymers (MIP) has been increasingly concerned because of advanced recognition efficiency. We here demonstrate a facile miniemulsion based polymerization to synthesize single hole hollow MIP particles for the recognition of bisphenol A (BPA). Uniform submicron products can be achieved through one-step polymerization in the aqueous dispersion, where the polymer seed has been swelled in the miniemulsion of the cross-linker and functional monomers together with the template molecules of BPA. After the removal of the seed and the template molecules by extraction, the electron microscopy characterization reveals bowl-like particles with a single hole on the concave surface. The unique single hole hollow structure is determined by the polymerization induced phase separation in the miniemulsion droplets and can be altered by monomer components. The characteristic of MIP is illustrated by the molecular recognition in the rebinding tests, where the particles prepared under the optimal formulation exhibit remarkable kinetics and desirable selectivity towards BPA in the mixed solution of methanol and water (20:80, v/v). The MIP particles with single hole hollow structure would be attractive in environmental and analytic fields for BPA decontamination. [ABSTRACT FROM AUTHOR]

The design and fabrication of polymer microspheres with structural complexity in Pickering emulsion systems is a pioneering topic in recent years. Herein we report a synthesis of structured and molecularly imprinted multicore rattle-type microspheres through a facile method based on the Pickering emulsion polymerization using silica nanoparticles as the only stabilizer. The void inside the sphere was induced by the polymerization-driven phase separation approach tailoring by the interface interaction. However, the imprinting template of bisphenol A (BPA) is found to serve also as the heterogeneous nuclei, whose superimposition on the polymerization induced phase separation creates the opportunities for the formation of the multicores encapsulated in the shell. A simple adjustment on the composition of the oil phase enabled the evolution of sphere internal structures from single void to multicores. Specifically, the reversibly incorporated BPA on the polymer spheres can be removed by extraction with the molecular information left and immobilized by crosslinking as the imprinted sites. The imprinted spheres can be used to selectively rebind BPA, which was comprehensively evaluated by a batch of rebinding experiments. The rattle-like microspheres recognized BPA molecules from their analogues and effectively removed them from the matrix with accelerated adsorption kinetics, which shows potential applications in the environmental or analytic fields where the removal or separation of BPA as an endocrine-disrupting chemical is in high demand. [ABSTRACT FROM AUTHOR]

Abstract: Herein polypyrrole-polystyrene (PPy-PS) hybrid hollow spheres have been prepared by a facile method. In the synthesis, pyrrole was oxidatively polymerized by FeCl3·6H2O in an emulsion of PS latex. The produced PPy deposited onto the surface of the PS particles, which were “dissolved” during the polymerization for the in-situ formation of hollow PPy spheres. The morphology of the hollow spheres was characterized by transmission electron microscope (TEM) and scanning electron microscopy (SEM). The size and size distribution of the hollow spheres were totally depended on that of the PS latex particles which can be adjusted conveniently. The PPy-PS hybrid structure of the shell of the hollow spheres was characterized by selective extraction using tetrahydrofuran (THF) and Fourier transform infrared (FTIR) spectroscopy. The formation process of the hollow spheres was traced by TEM. The probable mechanism for the formation of hollow spheres was also proposed in this work. The influences of the reaction conditions on the formation of the hollow structures have been studied in detail. [Copyright &y& Elsevier]

Abstract: Multilayer core–shell poly (styrene-butyl acrylate) latex particles were synthesized via semi-continuous emulsion polymerization, and the process was monitored by a dynamic laser scattering (DLS). The layers of the latex particles were designed to have progressively decreasing glass transition temperatures (T g) from the core (layer 1) to the outmost shell (layer 4), which was achieved by varying the mass ratio of butyl acrylate (BA) to styrene (St) in the synthesis of each layer. Divinylbenzene (DVB) was added as the crosslinking agent in each layer except for the outmost layer in order to ensure that a continuous film can be formed at room temperature. The damping properties of the formed films as well as the influences of synthesis variables, including the content of DVB added in the internal layers (i.e., layers 1, 2, and 3), the total mass ratio and sequence between layers 3 and 4, and the T g of each layer were studied by dynamic mechanical analysis (DMA). The results showed that four-layer core–shell latex particles with proper DVB content in each layer exhibited the best damping properties, with a broad effective damping range (tan δ >0.3) ranging from −12.0°C to 97.2°C. The widening of the damping peak can be explained by the formation of a gradient IPN structure in latex particles. Furthermore, the morphology of the formed films was studied by AFM in tapping mode. [Copyright &y& Elsevier]

Abstract: Core–shell polysilsesquioxane-poly(styrene-butyl acrylate-fluorinated acrylate) [PSQ–P(St-BA-FA)] hybrid latex particles were successfully prepared by seeded emulsion polymerization with polymethacryloxypropylsilsesquioxane (PSQ) synthesized by the hydrolysis and polycondensation of (3-methacryloxypropyl)trimethoxysilane (MAPTS) in the presence of emulsifiers as seeds. The chemical composition and core–shell morphology of the resultant hybrid particles were investigated by Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM), respectively. TEM and dynamic light scattering (DLS) analysis indicated that the core–shell hybrid particles were uniform and possessed narrow size distributions. The surface properties of the latex films produced from the core–shell hybrid particles were also investigated by contact angle (CA) analysis and X-ray photoelectron spectroscopy (XPS) analysis. The results proved the enrichment of fluorine on the film surface, and the latex films had high contact angles and low surface free energies. Optical measurements indicated that the incorporation of fluorinated acrylate onto PSQ particles can effectively reduce light reflectivity of the obtained transparent hybrid latex film. Atom force microscopy (AFM) characterization showed that the obtained hybrid latex film had a smooth surface. Additionally, thermogravimetric analysis (TGA) indicated that the PSQ–P(St-BA-FA) hybrid latex film had better thermal stability than the poly(styrene-butyl acrylate) [P(St-BA)] latex film. [Copyright &y& Elsevier]