Mingqiao Ge

Preparation and study on the structure and properties of rare-earth luminescent fiber:

In order to further explain the luminous properties of rare-earth luminescent fiber and promote various-product development of the fiber, in this research, rare-earth luminescent fiber was prepared by using rare-earth strontium aluminate as the rare-earth luminescent material, fiber-forming polymer PET as the matrix. The microstructure, composition and properties of rare-earth luminescent fiber were studied systematically based on tests and analysis with luminescent fiber, rare-earth luminescent materials and polyester fiber in detail. The results showed that the crystal structure of SrAl2O4: Eu2+, Dy3+ distributed in fiber was not destroyed by the polymer matrix and that the complex manufacturing process to ensure luminous properties of fiber performed well. Meanwhile, the structure and properties of luminescent fiber with no distinct changes were similar with that of the polyester fiber. The breaking tenacity and elongation of luminescent fiber in the wet state decreased respectively compared to the dry, and the breaking tenacity of polyester fiber was higher than luminescent fiber. The endothermic melting peak and glass transition temperature of luminescent fiber were slightly higher than that of polyester fiber. Decay curves of samples were successfully fitted by the sum of three exponential components with different decay times. Characteristic decay tended to be longer in luminescent fiber, while the initial luminance intensity of SrAl2O4: Eu2+, Dy3+ was higher than that of luminescent fiber.

Novel hollow α-Fe2O3 nanofibers via electrospinning for dye adsorption.

Nanomaterials such as iron oxides and ferrites have been intensively investigated for water treatment and environmental remediation applications. In this work, hollow α-Fe2O3 nanofibers made of rice-like nanorods were successfully synthesized via a simple hydrothermal reaction on polyvinyl alcohol (PVA) nanofiber template followed by calcination. The crystallographic structure and the morphology of the as-prepared α-Fe2O3 nanofibers were characterized by X-ray diffraction, energy dispersive X-ray spectrometer, and scanning electron microscope. Batch adsorption experiments were conducted, and ultraviolet-visible spectra were recorded before and after the adsorption to investigate the dye adsorption performance. The results showed that hollow α-Fe2O3 fiber assembles exhibited good magnetic responsive performance, as well as efficient adsorption for methyl orange in water. This work provided a versatile strategy for further design and development of functional nanofiber-nanoparticle composites towards various applications.

Research on the afterglow properties of red-emitting phosphor: SrAl2O4:Eu2+, Dy3+/light conversion agent for red luminous fiber

SrAl2O4:Eu2+, Dy3+/light conversion agent is a new composite luminescent material, which can emit red light in the darkness after being excited. The SrAl2O4:Eu2+, Dy3+ was prepared by means of solid-state reaction, and SrAl2O4:Eu2+, Dy3+/light conversion agent was fabricated by combining light conversion agent on to SrAl2O4:Eu2+, Dy3+ particles. In order to promote the afterglow properties of this red-emitting phosphors, several kinds of SrAl2O4:Eu2+, Dy3+/light conversion agent containing different light conversion agent were artificially manufactured, and the effect of manufacturing elements including the concentration of light conversion agent and environmental factor of heating temperature, drying temperature, stirring time on its luminescence property were investigated through evaluating their afterglow properties. The results showed that the light conversion agent and manufacturing process did not destroy the phase of SrAl2O4:Eu2+, Dy3+, and the red light were not emitted by SrAl2O4:Eu2+, Dy3+ just for the energy transferred from SrAl2O4:Eu2+, Dy3+ to light conversion agent. And the affecting factors of light conversion agent concentration, heating temperature, drying temperature, stirring time had different influence on the afterglow property of SrAl2O4:Eu2+, Dy3+/light conversion agent with increasing the concentration of light conversion agent, heating temperature, drying temperature, stirring time, the afterglow time and initial brightness of this phosphor increased and then decreased gradually.

Sustained broad-spectrum antimicrobial and haemostatic chitosan-based film with immerged tea tree oil droplets

For ideal wound-healing dressings, the chitosan-based films loaded with tea tree oil droplets were successfully fabricated by solution casting method. Tea tree oil emulsion droplets of about 200–300 nm in size were dispersed and immersed in chitosan films. Fourier transform infrared spectroscopy and differential scanning calorimetry measurement illustrated that the hydrogen-bonding interaction was formed between the amino and hydroxyl groups of chitosan and the hydroxyl groups of tea tree oil components to destroy the original hydrogen bond between chitosan molecules and change the physico-chemical properties of the films. With the increasing ratio of chitosan to tea tree oil, fluid absorption gradually decreased and water vapor permeability increased. The film with chitosan/tea tree oil ratio of 20:4 had identical hemostatic effect and non-cytotoxicity, and showed sustained growth inhibitory effect against S. aureus, E. coli and C. albicans. These results suggested that tea tree oil droplets played an important role in antimicrobial films and had a good potential to be incorporated into chitosan-based films which can be used in wound healing applications.

The effects of inorganic pigments on the luminescent properties of colored luminous fiber

Luminous fibers are produced by adding luminous pigments to regular manmade fibers to enable them to glow in the dark, while colored luminous fibers are produced by adding colored pigments to luminous fibers. In order to obtain a basic understanding of the effects of inorganic pigments on the luminescent properties of colored luminous fibers, five colored luminous fibers were prepared. Photoluminescence spectroscopy was used to investigate the effects of inorganic pigments on the luminescent properties of luminous fibers. The degree of crystallization of colored luminous fibers was reduced because of the addition of inorganic pigments and luminous materials, as revealed by X-ray diffraction data. Afterglow intensity of colored luminous fibers decreased with time, and the addition of inorganic pigments affected the intensity of luminous fibers. Compared with the white luminous fiber, the positions of the emission peaks were unaffected in the case of fibers colored with red, blue, and green pigments, but in the case of the fiber colored with the yellow pigment three excitation peaks were noted. Colored luminous fibers emitted colored light, which produced different visual stimulation to the human eyes. It was observed that the yellow luminous fiber had the largest visual perception brightness followed by white, green, red, and blue luminous fibers. The addition of inorganic pigments had certain effects on the dominant wavelengths of colored luminous fibers, but not on the color of the emitted light.

Quantum dots-hyperbranched polyether hybrid nanospheres towards delivery and real-time detection of nitric oxide.

In this work, novel hybrid nanosphere vehicles were synthesized for nitric oxide (NO) donating and real-time detection. The hybrid nanosphere vehicles consist of cadmium selenide quantum dots (CdSe QDs) as NO fluorescent probes, and the modified hyperbranched polyether (mHP)-based diazeniumdiolates as NO donors, respectively. The nanospheres have spherical outline with dimension of ~127 nm. The data of systematic characterization demonstrated that the mHP-based hybrid nanosphere vehicles (QDs-mHP-NO) can release and real-time detect NO with the low limit of 25 nM, based on fluorescence quenching mechanism. The low cell-toxicity of QDs-mHP-NO nanospheres was verified by means of MTT assay on L929 cells viability. The QDs-mHP-NO nanospheres provide perspectives for designing a new class of biocompatible NO donating and imaging systems.

Chemical recycling of waste poly(ethylene terephthalate) fibers into azo disperse dyestuffs

In this study, waste poly(ethylene terephthalate) (PET) fibers were chemically recycled into azo disperse dyestuffs. First, waste PET fibers were glycolytically degraded by excess ethylene glycol utilizing zinc acetate dehydrate as a catalyst. The glycolysis product, bis(2-hydroxyethyl) terephthalate (BHET), was purified through recrystallization and hydrolyzed into terephthalic acid (TPA). Thereafter, BHET and TPA were nitrated, reduced and azotized to obtain diazonium salts. Finally, the obtained diazonium salts were coupled with N,N-dimethylaniline to obtain azo disperse dyestuffs (dye A and dye B, respectively). The depolymerized products (BHET and TPA) and azo disperse dyestuffs (dyes A and B) were characterized by FTIR and 1H NMR spectroscopy. Nylon and polyester filaments were dyed with the synthesized azo dyestuffs with the dye bath pH ranging from 3.6 to 5.8. The performances of the dyestuffs were described by maximum absorption wavelength, K/S, L*, a* and b* values.

Organic-inorganic hybrid of chitosan/poly (vinyl alcohol) containing yttrium(III) membrane for the removal of Cr(VI)

In this present study, an organic-inorganic hybrid membrane was prepared by embedding yttrium(III) into chitosan matrix for the removal of Cr(VI) from aqueous solutions. Several techniques, including fourier infrared spectrum (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM) are employed to characterize the properties of the membrane. The mechanical properties of the membrane were also examined. The chitosan/poly(vinyl alcohol) containing yttrium(III) (CY) membrane was experimentally used for the removal of Cr(VI) ions from aqueous solution under the optimized conditions. The results showed that the adsorption capacity for the removal of Cr(VI) ions was enhanced when yttrium(III) was introduced. The adsorption data from the experiment were fit well by Langmuir isotherm. Based on Langmuir model, qm was calculated to be 38.48 mg g−1. Kinetic study results indicated that the adsorption process followed a pseudo-second-order kinetics.

Polyacrylonitrile/electroconductive TiO2 nanoparticles composite fibers via wet-spinning

For the first time, novel polyacrylonitrile (PAN)/electroconductive TiO2 (EC-TiO2) nanoparticles composite fibers have been successfully spun via wet-spinning. The composite fibers had uniform diameter and homogeneous surface. Moreover, at low content of EC-TiO2 nanoparticles, the composite fibers realized a transition from an insulator to a conductor. This work has provided a simple and effective avenue for the production of PAN/EC-TiO2 nanoparticles composite fibers that have great potential applications in the antistatic textiles.

The effects of DMSO on structure and properties of PVA/PEDOT:PSS blended fiber

In the present study, novel strong and conductive blended fibers composed of poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) and polyvinyl alcohol (PVA) were successfully fabricated via a wet-spinning process using spinning formulation prepared by doping DMSO into PVA/PEDOT:PSS aqueous solution. The effects of DMSO on structure and properties of PVA/PEDOT:PSS blended fibers were systematically investigated in detail by analyzing the changes in electrical conductivity, aggregation structure, conformational PEDOT chains, morphology and mechanical properties. The results showed that doping of DMSO induced significant conformational changes in PEDOT chains which in turn led to significant enhancement in electrical conductivity and smoother surface morphology as well as better mechanical properties of PVA/PEDOT:PSS blended fibers. The resultant DMSO-doped PVA/PEDOT:PSS blended conductive fibers exhibited an enhanced electrical conductivity up to 21.16 S cm-1. In addition, as the doping concentration of DMSO increased, the surface of blended fibers became less fluted and smoother. The Young’s modulus and tensile strength increased from 3.5 GPa and 115 MPa to 4.95 GPa and 145 MPa respectively, while the elongation at break decreased from 25 % to 17 %.