Narrowly distributed spherical core-shell nanogels were prepared by a two-step aqueous dispersion polymerization. Core particles composed of cross-linked temperature-responsive poly(Nisopropylacrylamide) (PNIPAM) were synthesized via aqueous dispersion polymerization and then used as nuclei for subsequent shell addition of pH-responsive poly(4-vinylpyridine) (P4VP). The morphology and structure of the core-shell particles were confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the size distribution was determined by dynamic laser light scattering (DLLS). Temperature-and pH-induced volume phase transitions of the latex particles were also investigated by DLLS. The results show that the P4VP shell does not significantly perturb the temperature-induced volume phase transition of the parent core whether P4VP is ionized or not, and the deswelling behavior differs significantly from that of other polyelectrolyte gels within which the ionic groups are randomly distributed.

A fluorescent Zn(2+) sensor 2-(hydroxymethyl)-4-methyl-6-((quinolinyl-8-imino)methyl)phenol (HMQP) based on the 8-aminoquinoline platform has been synthesized. This sensor displays high selectivity, sensitive fluorescence enhancement, strong binding ability, and ratiometric response to Zn(2+) in Tris-HCl (50 mM, pH 7.54), THF-H(2)O (9:1, v/v). And an obvious color change between HMQP and Zn(2+)-MQP(-) can be visually observed by the naked eye. The composition of the complex Zn(2+)-MQP(-) has been found to be 1:2 based on the fluorescence/absorption titration and further confirmed by X-ray crystallography.

In this article, the relationship between the mechanical properties of wood-plastic composite (WPC) parts fabricated by selective laser sintering (SLS) and the laser intensity is determined. Green parts were formed from WPC by SLS process, the SLS green parts had sufficient strengths for features to be built with relatively high dimensional accuracy. In order to improve the mechanical properties of the parts to better level, the post-processing -infiltration with wax -is used. Experiments for studying mechanical properties of WPC parts with laser intensity growing are carried on, the result is as following: because interfacial adhesion of copolyester and densification are improved with laser intensity growing, impact strength increased gradually either in green part style or in wax-infiltrated part style, tensile strength and bending strength of wax-infiltrated parts increased gradually. The tensile strength improved 191% and the bending strength improved 17%, with the increase in laser intensity from 226 Watt/mm 2 to 311 Watt/mm 2 ; the impact strength of green parts improved 543% and the impact strength of wax-infiltrated parts improved 147%, respectively, by increasing the laser intensity from 226 Watt/mm 2 to 340 Watt/mm 2 . But when the laser intensity is greater than 311 Watt/mm 2 , the tensile strength and bending strength decreased for further increasing of the laser intensity, leading to higher temperature, making the melt viscosity of the copolyester drop.

A new Zn(2+) fluorescent chemosensor N'-(3,5-di-tert-butylsalicylidene)-2-hydroxybenzoylhydrazine (H(3)L(1)) and its complexes [Zn(HL(1))C(2)H(5)OH](∞) (1) and [Cu(HL(1))(H(2)O)]CH(3)OH (2) have been synthesized and characterized in terms of their crystal structures, absorption and emission spectra. H(3)L(1) displays high selectivity for Zn(2+) over Na(+), K(+), Mg(2+), Ca(2+) and other transition metal ions in Tris-HCl buffer solution (pH = 7.13, EtOH-H(2)O = 8 : 2 v/v). To obtain insight into the relation between the structure and selectivity, a similar ligand 3,5-di-tert-butylsalicylidene benzoylhydrazine (H(2)L(2)), which lacks the hydroxyl group substituent in salicyloyl hydrazide compared with H(3)L(1), and its complex [Zn(2)(HL(2))(2)(CH(3)COO)(2)(C(2)H(5)OH)] (3), [Co(L(2))(2)][Co(DMF)(4)(C(2)H(5)OH)(H(2)O)] (4), [Fe(HL(2))(2)]Cl·2CH(3)OH (5), have also been investigated as a reference. H(3)L(1) exhibits improved selectivity for Zn(2+) compared to H(2)L(2). The findings indicate that the hydroxyl group substituent exerts an effect on the spectroscopic properties, complex structures and selectivity of the fluorescent sensor.