Yuanpeng Wu

A Novel Approach to Molecular Recognition Surface of Magnetic Nanoparticles Based on Host–Guest Effect

A novel route has been developed to prepared β-cyclodextrin (β-CD) functionalized magnetic nanoparticles (MNPs). The MNPs were first modified with monotosyl-poly(ethylene glycol) (PEG) silane and then tosyl units were displaced by amino-β-CD through the nucleophilic substitution reaction. The monotosyl-PEG silane was synthesized by modifying a PEG diol to form the corresponding monotosyl-PEG, followed by a reaction with 3-isocyanatopropyltriethoxysilane (IPTS). The success of the synthesis of the monotosyl-PEG silane was confirmed with1H NMR and Fourier transform infrared (FTIR) spectroscopy. The analysis of FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the immobilization of β-CD onto MNPs. Transmission electron microscopy (TEM) indicated that the β-CD functionalized MNPs were mostly present as individual nonclustered units in water. The number of β-CD molecules immobilized on each MNP was about 240 according to the thermogravimetric analysis (TGA) results. The as-prepared β-CD functionalized MNPs were used to detect dopamine with the assistance of a magnet.

Synthesis and characterization of UV-curable waterborne polyurethane acrylate possessing perfluorooctanoate side-chains

The dispersion of UV-curable waterborne polyurethane acrylate possessing perfluorooctanoate side-chains (FPUA) terminated with pentaerythritol triacrylate (PETA) was synthesized by incorporating fluorine groups into the side chains of the polyurethane macromolecular from condensation polymerization by using perfluorooctanoate glycerate (OF-diols) as chain extender, while the polyurethane macromolecular was synthesized from isophoronediisocyanate (IPDI), dimethylol propionic acid (DMPA), and poly (propylene glycol) (PPG) etc. The chain extender was prepared from 2,2-dimethyl-1,3-dioxolane-4-methyl perfluorooctanoate (OF-diols-pg) by acid hydrolysis with trifluoroacetic acid. The structure of FPUA was characterized by FTIR, NMR, elemental analysis, UV–vis and Mass spectra, and the properties of the synthesized FPUA emulsion were also discussed. The effect of fluorine content on the UV-curing dynamics was studied and the UV-curing speed decreased with increment in fluorine content. Contact angle measurements shown that the hydrophobic property of the surface greatly increased by incorporation of fluorine into the polyurethane chain. In addition, scanning electron spectroscopy (SEM) analysis was applied to characterize the morphology of the fracture surface of the UV-cured FPUA which became phase-mixed after annealing.

Green and Facile Synthesis of Gold Nanoparticles Stabilized by Chitosan

A green and facile method has been developed to prepare gold nanoparticles (Au NPs) coated by chitosan in aqueous solutions. Herein, Au NPs capped with chitosan which acted as both the reducing and stabilizing agents were prepared through a two-step route at low temperature. HAuCl4 and chitosan initially reacted for 6 h at room temperature, and subsequently the mixture reacted for another 1 hour at 35°C. Ultraviolet visible spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction spectroscopy results confirmed the presence of Au NPs. Transmission electron microscopy indicated that the nanoparticles were dispersed individually. The analysis of thermogravimetric analysis and Fourier transform infrared spectroscopy showed that chitosan was capped on the surface of Au NPs.

Use of HPHT autoclave to determine corrosion inhibition effect of poly(methyl methacrylate-co-N-vinyl-2-pyrrolidone) on carbon steels in 3.5% NaCl solution saturated with CO2

The influence of poly(methylmethacrylate-co-N-vinyl-2-pyrrolidone), P(MMA-co-VP), on corrosion of carbon steels (J55, N80, P110SS and C110 steels) in 3.5 wt% NaCl solution saturated with CO2 was evaluated using static high pressure and high temperature (HPHT) autoclave. The surface was further evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and contact angle measurements. Quantum chemical calculations have been used to evaluate the structural, electronic and reactivity parameters of the inhibitor on the steels surface. SEM, XRD and contact angle measurement studies reveal that the surface of metals are quite unaffected after use of inhibitor in 3.5% NaCl solution saturated with CO2.

SECM/SKP and SVET studies on mitigation of N80 steel corrosion by some polymers

Three polymers, namely PAMPS (P1), P(AMPS-co-NVP) (P2) and P(AMPS-co-DMC) (P3), synthesized by common solution polymerization (CSP) were investigated as corrosion inhibitors for N80 steel in 3.5 wt% NaCl flooded with CO2 by high temperature high pressure (HPHT) weight loss, electrochemical methods (EIS, Tafel), scanning electrochemical microscopy (SECM), scanning Kelvin probe (SKP), scanning vibrating electrode (SVET) techniques, and surface studies (UV-Visible, SEM). The P1 inhibitor exhibited the best inhibition efficiency among the polymers at 500 ppm concentration. The adsorption of the polymer derivatives obeyed the Langmuir isotherm. SECM measurements revealed a difference in the current on the steel surface with and without polymers. SKP and SVET showed the potential difference between the cathodic and anodic regions of the metal surface with and without inhibitors.

Extremely high photocatalytic activity of polymer nanospheres embedded with CdS nanoparticles prepared by a novel method

Abstract A novel, practicable and convenient route has been developed to prepare polymer nanospheres embedded with CdS nanoparticles which show an extremely high photocatalytic activity compared with other photocatalysts. In this method, polymer nanospheres were fabricated through the polymerization of cadmium dimethacrylate which was introduced into self-assembly system of chitosan and 3-mercaptopropionic acid. Then CdS nanoparticles were prepared insitu by inflating H2S into the polymer nanospheres.