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The fast development of Pickering emulsion systems inspires burgeoning demand on the universal synthesis platform for the surface modification of solid particle emulsifiers. In this work, a mild and convenient "visible light–mediated surface grafting through (VSGT)" strategy is proposed. Through the two-step strategy, silica nanoparticles (SNPs) were firstly modified by vinyl alkoxysilane and then used as the substrate for grafting homopolymer brushes via reversible addition-fragmentation chain transfer polymerization under the irradiation of a compact fluorescent lamp (CFL) light source. The whole process was proceeded at room temperature without tedious conditions and complex operations. Importantly, simply by changing the monomer types, hydrophilic acrylic polymer chains can all be grafted on SNP with controlled chain length and relatively uniform high surface densities including poly(acrylic acid) (PAA), poly(N,N-dimethylacrylamide) (PDMA), poly(N-isopropylacrylamide) (PNIPAM), and poly(diacetone acrylamide) (PDAAM). Through the synthesis platform, the interfacial performance of the surface-grafted nanoparticles exhibited as amendable working as Pickering emulsifiers in oil–water system, illustrated by the evolution of interfacial tensions and the inner structures of the corresponding Pickering emulsions. Moreover, the emulsion stabilized by SNP-g-PAA and SNP-g-PNIPAM showed pH and temperature triggered emulsification-demulsification behaviors, respectively, convincing the contribution of the surface grafted polymers and provide a feasible clue for the subtle design on the interfacial texture in advanced Pickering emulsions. [ABSTRACT FROM AUTHOR]

Proper building of polymer/polysilsequioxane composite is determined by deep-rooted structural variables. This work focuses on the fabrication of silane-grafted waterborne polyurethane (DWPU)/polyphenylsilsequioxanes (PPSQ) composites by blending and in-situ methods, respectively. By using blending method, PPSQ nanoparticle latexes were dispersed in DWPU. By using in-situ method, as the precursor of PPSQ, phenyltrimethoxysilane was mixed in DWPU, and PPSQ was expected to be generated via in-situ sol-gel reaction during film formation. We systematically investigated the influences of PPSQ and its incorporation method on the phase separation of films. The competition between a heterophase-triggered phase separation and a silane-based crosslinking was found during film formation. The intrinsically local ordering permutation of PU segments was interrupted more or less with PPSQ. Both surface composition and morphology were altered in correspondence to the different addition amount of PPSQ. Furthermore, optical, mechanical, and thermal resistances of composite films were also investigated for potential applications as coatings. [ABSTRACT FROM AUTHOR]

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]