Molecularly imprinted microspheres and nanospheres for di(2-ethylhexyl)phthalate prepared by precipitation polymerization

Molecularly imprinted microspheres (MIMs, >3 μm) and nanospheres (MINs, ≈450 nm) for the environmental endocrine disruptor di(2-ethylhexyl)phthalate (DEHP) were prepared by a precipitation polymerization (PP) procedure. The effect of the dispersive solvents acetonitrile (ACN) and cyclohexane (CH), the cross-linkers ethylene glycol dimethacrylate (EDMA) and trimethylpropane trimethacrylate (TRIM), and the template on particle size and morphology of polymers was investigated in detail by scanning electron microscopy (SEM) and BET adsorption isotherm determination. When used as HPLC stationary phase, the microspheres exhibited strong affinity for the template DEHP with an imprint factor (IF) higher than 8.0 in ACN/water (60:40, v/v) as mobile phase. Furthermore, baseline separation of DEHP from benzyl butyl phthalate (BBP) and dibutyl phthalate (DBP) could be achieved. In contrast, no or only poor separation could be observed with non-imprinted polymeric polymers (NIPs) or imprinted bulk polymers (MIB), respectively. Similarly, the obtained MINs exhibited an imprinting effect in pure ACN, i.e. the bond amount of DEHP was significantly higher compared to NIPs, as was shown in rebinding experiments. Besides their use as an HPLC stationary phase, MIMs might further be applicable for SPE sample cleanup, while MINs could be used as a recognition layer on sensor surfaces. Figure Molecularly imprinting of di(2-ethylhexyl)phthalate (DEHP)     

Synthesis of magnetic nickel spinel ferrite nanospheres by a reverse emulsion-assisted hydrothermal process

Nickel ferrite nanospheres were successfully synthesized by a reverse emulsion-assisted hydrothermal method. The reverse emulsion was composed of water, cetyltrimethyl ammonium bromide, polyoxyethylene(10)nonyl phenyl ether, iso-amyl alcohol and hexane. During the hydrothermal process, β-FeO(OH) and Ni_0.75Fe_0.25(CO₃)_0.125(OH)₂·0.38H₂O (INCHH) nanorods formed first and then transformed into nickel spinel ferrite nanospheres. The phase transformation mechanism is proposed based on the results of X-ray powder diffraction, transmission electron microscopy and energy-dispersive X-ray spectroscopy, etc. Nickel ferrite may form at the end of the INCHH nanorods or from the solution accompanied by the dissolution of β-FeO(OH) and INCHH nanorods. The X-ray photoelectron spectroscopy analysis shows that a few Fe³⁺ ions have been reduced to Fe²⁺ ions during the formation of nickel ferrite. The maximum magnetization of the nickel ferrite nanospheres obtained after hydrothermal reaction for 30 h is 55.01 emu/g, which is close to that of bulk NiFe₂O₄.     

Bulk electrolysis of Zn-phthalocyanine unveils self assembled nanospheres via anion binding

Stimuli responsive π-conjugated macrocyclic systems has shown significant attention in organic electronics, however, amongst them, porphyrins and phthalocyanines unveiled remarkable growth towards materials and biological applications. Herein, we report bulk electrolysis of Zn-phthalocyanine system (ZnPc-OMe) under potential difference of 1.5 V in chloroform results anion binding mechanism directs the formation of self-assembled nanospheres by diffusion controlled approach. Electrochemical and UV–Vis absorption studies of ZnPc-OMe suggest that anion (Cl⁻) binding ability towards ‘Zn‘ whilst applied potential leads to the formation of H⁺[(Cl)ZnPc-OMe]^- promote the enhanced current and charge generation. Microscopic analysis revealed that ZnPc-OMe and H⁺[(Cl)ZnPc-OMe]^- exhibit the nanosheets and spheres with an average diameter of 0.5–1 μm and 300–500 nm, respectively. Powder X-ray diffraction analysis and raman spectra revealed the changes in crystalline phase transitions via ion-dipole and π-π stacking interactions. Thus, these unique features are atypical for phthalocyanine derivative hitherto unknown.     

以聚合物乳胶为模板经表面引发原子转移自由基聚合制备空心二氧化硅纳米微球

均匀的空心纳米及微米球因具有可裁剪结构及良好的光学性能和表面性能,而具有非常广泛的应用前景,空心胶囊是一类重要的材料,它是通过不同的化学和物理方法,直接除去壳-核粒子的内核而获得的,目前主要是通过控制表面沉积。或利用静电相互作用层层组装。制备空心胶囊,但前者易于产生独立的无机粒子沉淀,后者的步骤太过繁琐。     

改性壳聚糖抗菌纳米微球的制备

以卤胺化合物为抗菌基团对壳聚糖接枝改性, 并制备成纳米微球, 提高壳聚糖的抗菌性能. 通过核磁共振和紫外光谱对改性壳聚糖进行结构表征; 探讨了改性壳聚糖浓度、 三聚磷酸钠浓度及两者体积比对纳米微球的形成和粒径分布的影响; 测定了纳米微球的抗菌性能. 结果表明, 在改性壳聚糖浓度为4.0 mg/mL, 三聚磷酸钠浓度为2.0 mg/mL时, 形成的纳米微球形态稳定, 粒径分布均匀, 氯化后的纳米微球可在30 min内杀灭10⁷ cfu(cfu为单位体积中的菌落总数)的金黄色葡萄球菌和大肠杆菌, 表现出优异的抗菌性能.     

Emulsion polymerization of styrene by horseradish peroxidase-mediated initiation

A new horseradish peroxidase (HRP)-catalyzed redox initiating system was successfully applied in the emulsion polymerization of styrene, producing stable polymer colloids and nanospheres. The particle size was about 30–50 nm with a diameter distribution (CV) 14–20% obtained by SEM. The molecular weight, was around 10⁵, and was around 10⁶. All the results were well consistent with the control, potassium persulfate (KPS)-initiating polymerization. The obtained experimental results supported a micelle mechanism similar to that of conventional emulsion polymerization of styrene.     

CuO Nanospheres Based Nonenzymatic Glucose Sensor

CuO nanospheres, synthesized by a simple one‐step hydrothermal method, have been applied to modify the glassy carbon (GC) electrode for sensitive nonenzymatic glucose detection. The CuO nanospheres modified electrode, compared to the Nafion modified GC electrode, exhibits an enhanced electrocatalytic property for direct glucose oxidation and shows a fast response and a high sensitivity for the amperometric detection of glucose. It has been determined that the dissolved oxygen is not involved in glucose oxidation and the high concentration of NaCl does not poison the electrode. These results also indicate that CuO nanospheres have great potential application in electrochemical detection.     

Synthesis of coryphantha elephantidens-like SnO2 nanospheres and their gas sensing properties

In this work, coryphantha elephantidens-like SnO₂ with porous structures were prepared successfully by a simple hydrothermal route, through adjusting the temperature of hydrotherm. Its morphology was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET). Compared to the regular nanospheres, the coryphantha elephantidens-like SnO₂ nanospheres had obviously higher gas-sensing response, owing to the special structure with large specific surface area (161.16 m² g^?1). It surprised us that the coryphantha elephantidens-like SnO₂ sensor could easily distinguish between ethanol and acetone, whose chemical property were similar. Moreover, it also exhibited wide measurement range, fast response speed (less than 10 s) and good repeatability at a low temperature (180 °C) to ethanol. The desirable specific surface area and pore volume were conducive to molecules adsorption and diffusion, which were believed to be the major cause of the improvement of gas sensing performance.     

On the complex refractive index of N-doped TiO2 nanospheres and nanowires in the terahertz spectral region

In this paper, the terahertz (THz) transmission measurement technique was applied to characterize titanium dioxide (TiO₂) nanospheres and nanowires subjected to thermal treatments under various conditions. Differences in the spectral features of the nanospheres and nanowires were observed due to treatment and annealing of the samples in different gas atmospheres. The observations made can be explained based on the formation of new phonon bands and/or widening of the phonon bands due to polymorphism. A singly subtractive Kramers Kronig dispersion relation was utilized to estimate the frequency-dependent real refractive index of the various samples, having a priori unknown sample thickness, from the absorbance data.     

Synthesis and characterization of poly(vinyl pyrrolidone)-capped bismuth nanospheres

Poly(vinyl pyrrolidone)-capped bismuth nanospheres were synthesized by a simple and convenient wet chemical method. In the process, bismuth nitrate was reduced by ethylene glycol in the presence of poly(vinyl pyrrolidone) (PVP) at 185 °C in air. PVP was used as a protecting agent to prevent oxidation of the sperical bismuth particles. PVP molecules were absorbed on the surface of bismuth nanospheres through the interaction of O–Bi bond which was confirmed by Fourier transform infrared (FT-IR) measurement. The thermal analysis shows the samples contained about 73 wt.% metallic bismuth. The optical absorption spectrum of poly(vinyl pyrrolidone)-capped bismuth nanosphere shows a strong absorption band at 275 nm.