A Novel Azo-Linked Polymer Bearing Trifluoromethyl Groups for I2 Capture.

In this work, a novel three nitro-group-bearing monomer 3,6-dinitro-9-(2-trifluoromethyl-4-nitrophenyl)-carbazole (Car-3NO2 -CF3 ) via a CN coupling reaction between 3,6-dinitro-9H-carbazole (Car-2NO2 ) and 2-chloro-5-nitrobenzotrifluoride is synthesized, and obtained single crystal and single crystal analysis data for this compound. The crystal system of Car-3NO2 -CF3 is monoclinic and it has a P 21/c space group. This new monomer (Car-3NO2 -CF3 ) is also utilized to synthesize a novel azo-linked polymer (Azo-Car-CF3 ). The trifluoromethyl group has polar CF bonds, and thus it is an effective functional group for the capture of iodine. Azo-Car-CF3 has great thermal stability with a mass loss of only 10% at 414 °C, as well as good chemical stability as is demonstrated by its low solubility in common organic solvents such as tetrahydrofuran (THF), acetone, methanol, ethanol, and N,N-dimethylformamide (DMF). The specific surface area of Azo-Car-CF3 can reach as high as 335 m2  g-1 . Azo-Car-CF3 exhibits an excellent capacity for iodine adsorption and can reach up to 1198 mg g-1 in cyclohexane solution, and its adsorption capacity for iodine vapor can get to 2100 mg g-1 . In addition, ethanol can be used to trigger the release of the captured iodine to be easily released from Azo-Car-CF3 .

Facile method for the fabrication of robust polyelectrolyte multilayers by post-photo-cross-linking of azido groups.

In this letter, we have developed a facile method to enhance the stability of polyelectrolyte multilayers. We fabricate conventional polyelectrolyte multilayers of PAH/PAA through electrostatic layer-by-layer (LbL) assembly and then postinfiltrate photosensitive cross-linking agent 4,4'-diazostilbene-2,2'-disulfonic acid disodium salt into the LbL films. After cross-linking by UV irradiation, the stability of the photo-cross-linked multilayer is highly improved as evidenced by the lack of dissolution under ultrasonication in saturated SDS aqueous solutions for 10 min. Moreover, by taking advantage of the different stability of the LbL film before and after UV irradiation, a patterned surface can be achieved.

Self-assembly and chiroptical property of poly(N-acryloyl-L-amino acid) grafted celluloses synthesized by RAFT polymerization.

Three amphiphilic poly(N-acryloyl-L-amino acid) grafted celluloses were prepared by RAFT polymerization of N-acryloyl-L-amino acid, where amino acid is alanine, proline or glutamic acid, onto cellulose backbones. The chemical structure and solution properties of the brush copolymers were characterized with FTIR, NMR and wide angle X-ray diffraction (WAXD). The thermal stability of the brush copolymers was estimated by thermal gravimetric analysis (TGA). Circular dichroism (CD) and specific rotation measurements confirmed that these grafted celluloses had characteristic chiroptical properties. The amphiphilic brush copolymers self-assembled into micelles in the aqueous solution as confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses. The micellar aggregates showed a tunable pH-responsive property and disaggregated to form unimolecular micelles at higher pH in diluted solutions. The brush copolymers have potential applications in controlled drug release and high-performance liquid chromatography, and so forth.