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In this article, a preparation method of a water‐dispersible photoinitiator, which can be used for three‐dimensional (3D) printing of the hydrogel and can be initiated under visible light is proposed. The oil‐soluble photoinitiator 2,4,6‐trimethylbenzoyl‐diphenylphosphine oxide (TPO) is nano‐wrapped with surfactant Tween 20 to obtain the oil‐in‐water (O/W) miniemulsion, and then it is successfully transformed into water‐dispersible nanospheres without the use of organic solvents or crystallization inhibitors. The morphology and optical properties were characterized by transmission electron microscopy (TEM), particle size analysis and ultraviolet–visible (UV–Vis) spectroscopy. Subsequently, the water‐dispersible nano‐photoinitiator was used to realize the photopolymerization of acrylamide/N,N′‐methylenebisacrylamide hydrogel under visible light (405 nm). Then, the micromorphology of the photocuring process of the hydrogel was observed by TEM and the photocuring activity of the initiator was evaluated. Finally, a viscosifier suitable for AM/MBA hydrogel system was screened out, and the direct ink writing (DIW) 3D printing of the hydrogel was successfully realized by using this nano‐photoinitiator. [ABSTRACT FROM AUTHOR]

Well-defined PANI rhombic plates are produced via a cetyl trimethyl ammonium bromide (CTAB) micellar soft template route in low acid environment. Lamellar micelles consisting of CTAB and ammonium persulfate (APS) molecules not only serve as both soft templates and oxidant for oxidative polymerization of aniline, but also provide intermolecular interactions to assemble two-dimensional PANI sheets to three-dimensional rhombic plates. Detailed mechanistic studies meanwhile reveal that fabricating such regular rhombic plates cannot be separated from the synergistic effect of the optimal pH value and suitable anions. The prepared PANI rhombic plates exhibit water dispersibility, processability, and flow-induced color variation, which is supposed to be attributed to the intermolecular interactions between residual CTAB molecules and PANI molecules. Using these rhombic plates as a model system, the results and strategies presented here provide insight into the general scheme of morphology and dimension control in the low acid environment for conducting polymers. [ABSTRACT FROM AUTHOR]

ABSTRACT In this contribution, we reported a facile synthesis of poly(methyl methacrylate)- block-poly( N-vinyl pyrrolidone) (PMMA- b-PVPy) diblock copolymers via sequential radical polymerizations mediated by isopropylxanthic disulfide (DIP). It was found that the radical polymerization of N-vinyl pyrrolidone (NVP) mediated by DIP was in a controlled and living manner. In contrast, the polymerization of methyl methacrylate mediated by DIP displayed the behavior of telomerization, affording xanthate-terminated PMMA with a good control of molecular weights while the conversion of monomer was not very high. The xanthate-terminated PMMA can be successfully used as the macromolecular chain transfer agent for the polymerization of NVP via RAFT/MADIX process and thus PMMA- b-PVPy diblock copolymers can be successfully synthesized via sequential radical polymerization mediated by isopropylxanthic disulfide. One of these diblock copolymers was incorporated into polybenzoxazine and the nanostructured thermosets were obtained as evidenced by transmission electron microscopy, small angle X-ray scattering, and dynamic mechanical thermal analysis. The formation of nanostructures in polybenzoxazine thermosets was ascribed to a reaction-induced microphase separation mechanism. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 952-962 [ABSTRACT FROM AUTHOR]