Karrooite green pigments doped with Co and Zn: Synthesis,color properties and stability in ceramic glazes

The solid-state synthesis and stabilization of Co doped (Mg_1−xCo_xTi₂O₅), Zn doped (Mg_1−xZn_xTi₂O₅) and Co- and Zn-codoped karrooite solid solutions (Mg_0.8−xZn_0.2Co_xTi₂O₅ and (Mg_0.5Zn_0.5)_1−xCo_xTi₂O₅) were investigated. In addition, the optical spectra, color properties and technological performance of (Co,Zn)-karrooite compositions as new green ceramic pigments were also analyzed. XRD characterization revealed for the first time the high solid solubility of Zn²⁺ in MgTi₂O₅ karrooite at 1200 ºC (between 60 and 80 mol% per Mg or karrooite formula unit). In contrast, the reactivity and stabilization of karrooite phase decreased in the case of Co²⁺ doping. Interestingly, codoping with Zn²⁺ ions at high molar ratios (Zn:Mg ratio equal to 1:1) enhanced the reactivity and enabled the stabilization of (Co,Zn)-MgTi₂O₅ karrooite solid solutions, even with high Co²⁺ loadings (20 mol% per karrooite formula unit). The (Co,Zn)-MgTi₂O₅ pigments exhibited yellowish-green colors associated to Co²⁺ ions allocated in octahedral M1 and M2 sites of karrooite lattice, and becoming more intense and less yellow the higher the Co content. However, Zn²⁺ codoping produced less saturated green colors with similar green but lower yellowish hues. The obtained pigments were not stable enough within the tested ceramic glazes, giving rise to turquoise colorations due to cobalt leaching and incorporation into tetrahedral sites of the glassy phase. The stability of Co-karrooite green pigments was higher in a Ca- and Zn-enriched ceramic glaze (B) fired at a higher temperature (1050 °C).     

Synthesis and coloring properties of novel stablized green Ni0.15MgxAl2(0.85-x)Ti1.15+xO5 pigments

Novel stablized green Ni_0.15Mg_xAl_2(0.85-x)Ti_1.15+xO₅ (0 ≤ x ≤ 0.25) pigments were prepared by solid-state method using Ni₂O₃ as colorant and Mg(CH₃COO)₂‧4H₂O as auxiliary stabilizer. The synthesised pigments were characterized via XRD, XPS, SEM, TEM, UV-Vis, and automatic colorimeters. The results show that Mg-doping increases the oxygen vacancies, resulting in a positive shift of the binding energy of Ni²⁺ irons. The formation of Ni_0.15Mg_xAl_2(0.85-x)Ti_1.15+xO₅ solid solution greatly increases the energy transfer energy and shifts the emission to lower wavelengths (530 nm), corresponding to the visible diffuse reflection of green light. The chromaticity of the pigment changed little (L*=72.51, a*=−18.16, b*=20.94) at 1200 ℃ for 10 h, showing excellent thermal stability. The properties especially excellent thermal stability makes it promising novel green pigments in ceramic industry application.     

Adsorption isotherms of pigments from alkali-refined vegetable oils with clay minerals

Adsorption isotherms of pigments from alkali-refined oils (rapeseed, soybean, wheatgerm, safflower, corn, cottonseed and sunflower) were measured to investigate the applicability of the Langmuir and Freundlich equations and to elucidate the adsorption characteristics of pigments on sepiolites and standard activated clay. The Freundlich equation was more applicable to the experimental adsorption isotherms. The equilibrium amount adsorbed, acidity, pore size distribution and inflection of the Freundlich isotherms could be explained by assuming that pigments were adsorbed on the stronger acid sites in smaller pores at low concentration, and then in the larger ones when the concentration increased. The amount adsorbed increased with a rise in adsorption temperatures from 70 to 110°C, and the heat of adsorption was below 10 kcal/mol. The results indicate that pigments were physically adsorbed on the acid sites activated at higher adsorption temperatures.     

Boronic acid‐based thin films that show saccharide‐responsive multicolor changes

A novel saccharide sensor that displays a distinct color change resembling a “traffic signal” was developed. By copolymerizing boronic acid and amine monomers on a glass plate, a boronic acid‐containing thin film was obtained. Anionic blue and yellow dyes were adsorbed on the thin film, and the film was immersed in aqueous saccharide solutions containing a cationic red dye. With increase in the saccharide concentration in the solution, the thin film changes color from green to red via yellow. The observed distinct changes in color were attributed to a stepwise release and binding of dyes. The sensitivity of the saccharide sensor was dependent on the monomer composition of the thin film and increased with increasing the boronic acid content. The pH of the saccharide solution was another key factor affecting the sensing behavior, and glucose‐responsive color changes were significantly enhanced at pH 7.8. By optimizing these conditions, significant color changes in response to glucose were achieved. Saccharide selectivity was found to be in the following order: fructose > glucose > galactose = mannose > sucrose. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42679.     

Synthesis and characterization of magnetic and fluorescent styrene co‐polymer nanofiber

F luorescent and magnetic poly(styrene) (PS) based random co‐polymer nanofiber was synthesized in a controlled manner via chemical polymerization in three steps. A fluorescent and magnetic nanohybrid {Fe₃O₄/Congored (CR)} was separately prepared and chemically grafted onto the epichlorohydrin (ECH) units of the random co‐polymer. Characterizations of the above synthesized polymers were done with the help of Fourier transform infrared (FTIR) spectroscopy, UV–visible spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, fluorescence emission spectroscopy, field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) measurement, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and gel permeation chromatography (GPC) like analytical techniques. The FESEM results indicated that after the grafting of nanohybrid onto the random co‐polymer backbone, the polymer exhibited a nanofiber like morphology. Due to the surface functionalization and encapsulation reactions, the magnetic moment value of the nanohybrid and its nanocomposites were found to be reduced. Synthesis and characterization of magnetic and fluorescent random co‐polymer based nanofiber is the primary target of the present investigation and its application is extended to the catalysis field. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42796.     

利用标志法研究钒—硅酸锆蓝色颜料的生成机理

标志法用来研究钒-硅酸锆蓝色颜料形成过程中的离子移动问题,借此了解该颜料的生成机理。结果表明Si^4 和Zr^4 中Si^4 是唯一可以移动的离子;NaF的加入有利于SiO2的玻璃化,因而对硅离子的迁移有一定贡献,但其移动更依赖于NaF和NH4VO3反应所形成的液相。此外,ZrO2的溶解也是硅酸锆生成的一个限制因素。     

SNAP‐Tag‐Based Subcellular Protein Labeling and Fluorescent Imaging with Naphthalimides

Genetically encoded technologies provide methods for the specific labeling and imaging of proteins, which is essential to understand the subcellular localization of these proteins and their function. Herein, we employed naphthalimide, an efficient two‐photon fluorophore, to develop O⁶‐benzylguanine (BG) derivatives for specific labeling of subcellular proteins and fluorescent imaging through the SNAP‐tag. Three naphthalimide–BG derivatives, TNI‐BG, QNI‐BG, and ONI‐BG, were conveniently synthesized through modular “click chemistry” in high yields. All of them showed high labeling efficiency with SNAP‐tag in solution (≈1–2×10³ s^?1 m ^?1) and in bacteria. Among them, ONI‐BG showed high specificity to diffused, histone H2B and mitochondria COX8A targeted SNAP‐tag in mammalian cells. The protein‐labeled naphthalimides exhibited high two‐photon absorption cross‐sections, which indicated their potential application in protein‐specific two‐photon fluorescent imaging, such as two‐photon fluorescent lifetime imaging and two‐photon multicolor imaging. Therefore, ONI‐BG is a versatile tool that can be used to track subcellular proteins through multiple fluorescent techniques.     

Photochromic properties of color‐matching,double‐shelled microcapsules covalently bonded onto cotton fabric and applications to outdoor clothing

In this research, we aimed to apply color‐matching, double‐shelled microcapsules to deal with outdoor‐clothing sunscreen‐indicator identifications on cotton fabrics with a covalent‐bonding coating method; this method allows one to display both the UV intensity and a warning. The color‐property characteristics of color‐matching‐double‐shelled‐photochromic‐microcapsule–treated patterns on cotton fabrics under various sunshine irradiation intensities are very close to those of inkjet‐printing color‐gradation patterns, which indicate sunshine irradiation intensities. Color‐matching, double‐shelled microcapsules were obtained by the addition of red double‐shelled microcapsules into yellow double‐shelled microcapsules. We increased the weight ratio of the red microcapsules and added blue double‐shelled microcapsules into the red double‐shelled microcapsules when the weight ratio of blue microcapsules was increased. Color‐matching, double‐shelled photochromic microcapsules, whose yellow/red/blue weight ratios were 5.6/0/0, 4.8/0.8/0, 2.4/3.2/0, and 0.8/4.8/0–0/0/5.6, presented distinct color‐property characteristic changes under various irradiation intensities and presented a good color identification; a rather dark, bright color; and good laundering durability of covalent bonding on cotton fabrics. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44698.     

Fabrication and photocatalytic behavior of a novel nanocomposite hydrogels containing Fe‐octacarboxylic acid phthalocyanine

A novel poly(ethylene glycol)‐based nanocomposite hydrogels containing Fe‐octacarboxylic acid phthalocyanine (FeOCAP)/magnetic attapulgite was successfully synthesized by in situ polymerization. Fourier transform infrared spectroscopy result showed the FeOCAP/magnetic attapulgite was successfully introduced into the hydrogels matrix. Besides, the hydrogen bond interactions existed between FeOCAP/attapulgite and hydrogels, which acted as the crosslink points in the hydrogels network, and meanwhile, stabilized the nanoparticles in hydrogel without phase separation. Photocatalytic activity studies confirmed that the as‐prepared nanocomposite hydrogels had excellent photocatalytic activity for rhodamine B photodegradation, as compared to the pure hygrogels. The rhodamine B removal percentage of the hydrogels could reach nearly 100% and the kinetics of photocatalytic degradation reaction was described by the Langmuir–Hinshelwood kinetics models. The hydrogels could be reused more than five times without losing any photodegradation ability, which indicated that the hydrogels would be potentially useful in dyes wastewater treatments. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45428.