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1.
The complex nature of spinal cord injuries has provided much inspiration for the design of novel biomaterials and scaffolds which are capable of stimulating neural tissue repair strategies. Recently, conductive polymers have gained much attention for improving the nerve regeneration. In our previous study, a three-dimensional (3D) structure with reliable performance was achieved for electrospun scaffolds. The main purpose in the current study is formation of electrical excitable 3D scaffolds by appending polyaniline (PANI) to biocompatible polymers. In this paper, an attempt was made to develop conductive nanofibrous scaffolds, which can simultaneously present both electrical and topographical cues to cells. By using a proper 3D structure, two kinds of conductive scaffolds are compared with a non-conductive scaffold. The 3D nanofibrous core-sheath scaffolds, which are conductive, were prepared with nanorough sheath and aligned core. Two different sheath polymers, including poly(lactic-co-glycolic acid) PLGA and PLGA/PANI, with identical PCL/PANI cores were fabricated. Nanofibers of PCL and PLGA blends with PANI have fiber diameters of 234±60.8 nm and 770±166.6 nm, and conductivity of 3.17×10-5 S/cm and 4.29×10-5 S/cm, respectively. The cell proliferation evaluation of nerve cells on these two conductive scaffolds and previous non-conductive scaffolds (PLGA) indicate that the first conductive scaffold (PCL/ PANI-PLGA) could be more effective for nerve tissue regeneration. Locomotor scores of grafted animals by developed scaffolds showed significant performance of non-conductive 3D scaffolds. Moreover, the animal studies indicated the ability of two new types of conductive scaffolds as spinal cord regeneration candidates.  相似文献   

2.
Application of electrospun nanofibrous scaffolds has received immense attention in tissue engineering. Fabrication of scaffolds with appropriate electrical properties plays a key role in neural tissue engineering. Since fibers orientation in the scaffolds affects the growth and proliferation of the cells, this study aimed to prepare aligned electrospun conductive nanofibers by mixing 1 %, 10 % and 18 % (w/v) doped polyaniline (PANI) with polycaprolactone (PCL)/poly lactic-coglycolic acid (PLGA) (25/75) solution through the electrospinning process. The fibers diameter, hydrophilicity and conductivity were measured. In addition, the shape and proliferation of the nerve cells seeded on fibers were evaluated by MTT cytotoxicity assay and scanning electron microscopy. The results revealed that the conductive nanofibrous scaffolds were appropriate substrates for the attachment and proliferation of nerve cells. The electrical stimulation enhanced neurite outgrowth compared to those PLGA/PCL/PANI scaffolds that were not subjected to electrical stimulation. As polyaniline ratio increases, electric stimulation through nanofibrous PLGA/PCL/PANI scaffolds results in cell proliferation enhancement. However, a raise more than 10 % in polyaniline will result in cell toxicity. It was concluded that conductive scaffolds with appropriate ratio of PANI along with electrical stimulation have potential applications in treatment of spinal cord injuries.  相似文献   

3.
Polyaniline (PANI) and shell membrane composites have been synthesized via chemical oxidative polymerization of aniline in the presence of shell membrane. Combination of surfactant, PANI, and shell membrane allows production of conductive textile with smooth surface. Fourier transform infrared spectroscopy (FTIR) measurements suggest that the oxidation degree of PANI was affected by the initial ratio of shell membrane vs. monomer amount. The PANI/shell membrane composites were characterized with UV-vis absorption spectroscopy, electron spin resonance (ESR) spectroscopy. Electrical conductivity of the composites was measured with four-probe method. The surface of the composites was observed with scanning electron microscopy (SEM). Thermal stability of the composites was discussed with the result of thermogravimetric analysis.  相似文献   

4.
Electrical conductive nanocomposite fibers were prepared with polyaniline (PANI), polyacrylonitrile (PAN) and multi-walled carbon nanotubes (MWCNTs) via electrospinning. The morphology and electrical conductivity of the PANI/PAN/MWCNTs nanocomposite fibers were characterized by scanning electron microscope (SEM) and Van De Pauw method. Electrical conductivity of nanocomposite fibers increased from 1.79 S·m?1 to 7.97 S·m?1 with increasing the MWCNTs content from 3.0 wt% to 7.0 wt%. Compared with PANI/PAN membranes, the mechanical property of PANI/PAN/MWCNTs nanocomposites fiber membranes decreased. The microwave absorption performance of composite films was analyzed using waveguide tube, which indicated that with the thickness increasing the value of RL reduced from ?4.6 to ?5.9 dB.  相似文献   

5.
A novel electrically conductive nanocomposite consisting of poly(N-vinylpyrrolidone) (PVP) modified polyaniline (PANI) and cloisite clay nanoparticles was obtained via insitu polymerization method. The synthesized nanocomposite was characterized using FT-IR, XRD, conductivity measurement and cyclic voltammetry techniques. The electrical conductivity measurements of prepared nanocomposite showed that the nanocomposite is electrically conductive. Also cyclic voltammetry studies revealed that the synthesized nanocomposite is electro active. Electrochemical corrosion studies including open circuit potential measurements and tafel tests were carried out in various corrosive environments to evaluate the anticorrosive property of the nanocomposite coating on iron samples. Results showed that the coating of this nanocomposite on iron was useful in decreasing corrosion current and corrosion rate of iron in comparison with bare iron and pure polyaniline coated samples. A positive shift in corrosion potential and a significant decrease in corrosion current were observed for nanocomposite coated iron samples in sodium chloride 3.5 %, hydrochloric acid 0.1 M and sulfuric acid 0.1 M solutions.  相似文献   

6.
Enhanced electrical conductivity of cotton fabrics coated with polyaniline (PANI) and PANI/carbon coated Fe (Fe@C) and carbon coated Co (Co@C) metal nanoparticles (NPs) composites were investigated. PANI/metal nanoparticle (NP) composites were fabricated with a surface initialized polymerization method and silanization helped with chemical bonding to cotton. The volume resistivity of the samples and structural characterizations were assessed by relevant methods. The results showed that enhanced electrical conductivity, thermal stability and magnetization were obtained via polymeric nanocomposites (PNC) and all these findings revealed that PANI/metal NP PNC coated cotton fabrics would exhibit good level electromagnetic shielding performance as a function of combined electrical conductivity and magnetization which is the objective of our future studies.  相似文献   

7.
In this study starch-montmorillonite/polyaniline (St-MMT/PANI) nanocomposite was synthesized by chemical oxidative polymerization of aniline in the presence of starch-montmorillonite nanocomposite dispersion. The prepared ternary nanocomposite was characterized using FT-IR, XRD, SEM, TGA and TEM techniques. XRD patterns combined with TEM results confirmed the intercalation of MMT in the starch matrix. SEM micrographs revealed the growth of polyaniline over the surface of the St-MMT nanocomposite. The St-MMT/PANI nanocomposite was used for the adsorption of a reactive dye. Batch removal experiment results showed complete removal of dye in a very short contact time. Further investigations indicated that the removal mechanism was based on both the adsorption and electrostatic attraction between nanocomposite and dye molecules. The experimental data were well fitted to the Langmuir isotherm and pseudo-second-order kinetic model. The adsorption capacity of reactive dye on St-MMT/PANI nanocomposite was 91.74 mg g?1. All these results demonstrated the effectiveness of the hybrid system as an efficient adsorbent for removal of reactive dyes from textile effluents.  相似文献   

8.
In order to fabricate textile-based flexible VOC sensors, two conductive polymers such as polyaniline and poly(3,4-ethylenedioxythiophene)-poly(styrene-sulfonate) (PEDOT:PSS) were used as VOC-sensing materials, and various porous organic membranes were used as base substrates on which the conductive polymers were coated. Electrical resistance change of conductive polymers by adsorption of VOCs was measured. Polyaniline showed better sensitivity than PEDOT:PSS. Porous high density polyethylene membrane exhibited the most stable signal reproducibility and dimensional stability of membrane itself. Even after covering with additional high density polyethylene membrane to protect conductive polyaniline inside, the stable signals were still obtained during repeated measurement.  相似文献   

9.
In this paper the feasibility of interlacing current-carrying metallic (conductive) filaments in a rotational permanent magnetic field is investigated. The work contains two parts. Firstly, the effect of magnetic forces on current-carrying metallic filaments in a rotational permanent magnetic field is theoretically studied. In addition, the behavior of a filament under magnetic forces is mechanically analyzed. Secondly, in accordance with the theoretical analysis, a prototype of the proposed system is designed and tested. The experimental results prove the capability of the method to interlace metallic filaments. The proposed method can be employed as a kernel in order to reach a frictionless twister system for other conductive filaments.  相似文献   

10.
In this work, a simple and low cost method based on screen printing is presented to synthesize a conductive silver pattern on aramid fabric. The aramid fiber was treated with (3-mercaptopropyl)-trimethoxysilane to introduce a tail mercapto group promoting the ordered binding of silver nanoparticles. SEM and AFM images indicated a uniform distribution of silver nanoparticles on fiber surface. FTIR and XRD patterns confirmed the silver layer on the fibers. Furthermore, the electrical property of conductive fiber was characterized by conductive AFM and a digital multimeter, the surface resistance of conductive fabric was as low as 0.20 Ω/cm. And single fiber tensile test indicated that the mild treating process has no significant influence on the mechanical properties of the fiber.  相似文献   

11.
This paper reports the results from the modelling of electrical resistance of polyester reinforced nonwoven fabrics used for light conveyor belts having conductive PA6 fibres and the same value of fabric volume fraction. The modelling was carried out on the basis of nonwoven construction parameters (the content of conductive fibres in nonwoven layers, fabric thickness), a two-probe method of electrical resistance measurement using flat electrodes and common ohmmeter, and a deterministic modelling method, e.g. statistical factor analysis. The results show very good agreement between the experimental and predicted values of conveyor belts’ electrical resistance. The proposed model provides guidelines for the engineering of conveyor belts in order to fit the prescribed electrical resistance.  相似文献   

12.
茶白星病是我国茶区常发真菌病害,近年发生面积及为害程度呈上升趋势,不利于我国茶产业的可持续发展。本文重点介绍了茶白星病病原菌的鉴定,并进一步综述其分布与为害、发生规律和防控措施,以供茶叶技术人员和生产者参考。  相似文献   

13.
The present work described the development of multifunctional, electrically conductive and durable fabrics by coating of silver and copper particles using a dipping-drying method. The particles were directly grown on fabric structure to form electrically conductive fibers. Particles were found to fill the spaces between the microfibers, and were stacked together to form networks with high electrical conductivity. The electrically conductive fabrics showed low resistance with high stretch ability. The utility of conductive fabrics was analyzed for electromagnetic shielding ability over frequency range of 30 MHz to 1.5 GHz. The EMI shielding was found to increase with increase in concentration of copper and silver particles. Furthermore, the heating performance of the copper and silver coated fabric was studied through measuring the change in temperature at the surface of the fabric while applying a voltage difference across the fabric. The maximum temperature (119°C for silver and 112°C for copper) were obtained when the applied voltage was 10 V. Moreover, the role of deposited particles on antibacterial properties was examined against pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. At the end, the durability of coated fabrics was examined against several washing cycles. The fabrics showed good retention of the particles, proved by small loss in the conductivity of the material after washing.  相似文献   

14.
A detailed study of electromagnetic shielding effectiveness (EMSE) of woven fabrics made of polyester and stainless steel/polyester blended conductive yarn was presented in this research work. Fabrics with different structures were analyzed and their shielding behavior was reported under different frequencies. Shielding efficiency of fabric was analyzed by vector network analyzer in the frequency range of 300 kHz to 1.5 GHz using coaxial transmission line holder. The effects of different fabric parameters such as weft density, proportion of conductive weft yarn, proportion of stainless steel content, grid openness, weave pattern and number of fabric layers on EMSE of fabrics were studied. The EMSE of fabric was found to be increased with increase in proportion of conductive yarn in the weft way. With increase in overall stainless-steel content in the fabric, the EMSE of fabric was increased. As such weave is considered, it did not have significant effect on EMSE of fabrics. But fabric with lower openness and aperture ratio showed better conducting network, hence better shielding. With increase in number of layers of fabric and ply yarns, EMSE of fabric was increased.  相似文献   

15.
Wool yarns were coated with conducting polypyrrole by chemical synthesis methods. Polymerization of pyrrole was carried out in the presence of wool yarn at various concentrations of the monomer and dopant anion. The changes in tensile, moisture absorption, and electrical properties of the yarn upon coating with conductive polypyrrole are presented. Coating the wool yarns with conductive polypyrrole resulted in higher tenacity, higher breaking strain, and lower initial modulus. The changes in tensile properties are attributed to the changes in surface morphology due to the coating and reinforcing effect of conductive polypyrrole. The thickness of the coating increased with the concentration of p-toluene sulfonic acid, which in turn caused a reduction in the moisture regain of the wool yarn. Reducing the synthesis temperature and replacing p-toluenesulfonic acid by anthraquinone sulfonic acid resulted in a large reduction in the resistance of the yarn.  相似文献   

16.
High thermal conductive polymer composites have recently attracted much attention, along with the quick development to the electronic devices toward higher speed. The addition of high thermal conductive fillers is an efficient method to solve this problem. Here, we introduced superfullerene (SF), a novel zero-dimensional carbon-based filler, and incorporated into PVDF by a solution method. The effects of SF filler on the thermal conductivity of PVDF composites were systematically investigated. It was found that PVDF composites exhibited an improvement in thermal conductivity at a low SF loading. PVDF composites with only 5 wt% SF filler present the thermal conductivity value of 0.365 Wm-1K-1, which is as much as 121 % enhancement in comparison with that of neat PVDF. In view of the excellent thermal transport performance, the composites may enable some applications in thermal management in the future.  相似文献   

17.
Compost leachate poses a threat to the environment because it contains many organic and inorganic pollutants. Chemical Oxygen Demand (COD) has been reported at values above 5000 mg/l O2. Heavy metals, such as nickel, lead, chromium are also present within these waters. Thus, in order to comply with the increasingly stringent environmental quality standards such contaminants must be removed effectively. The research approach in this paper is directed towards chelating pre-treatment procedures. Nontoxic and biodegradable biopolymer chitosan was used as a chelator for the removal of dissolved metals from compost leachate. The influence of chemical conditions regarding the chelation efficiency was studied in model solutions. The optimal treatment conditions were applied onto compost leachate which was analysed further regarding metals. In addition, the influence of chitosan was studied on compost leachate toxicity. The most important aspect of this paper is to demonstrate the potential of waste chitosan recycling. Thus, the chitosan chelates were subjected to the electrospinning procedure in order to develop new nano-porous structures, such as, for example, conductive textiles.  相似文献   

18.
Conductive aramid fiber with nickel-copper composite coating is prepared by consecutive steps of metalation swelling, sensitization, activation, nickel electroless deposition, and copper electroless deposition, respectively. The metalation swelling of aramid fiber makes the follow-up sensitization and activation feasible. The as-prepared samples are characterized by SEM, TEM, XRD and XPS. After metalation swelling, the aramid fibers look like cotton fibers with numerous nano-scale pits of 50–300 nm in diameter. Pd metal as nuclei for Ni crystal growth with the size of 10±5 nm is originated from Pd2+, which can be reduced to Pd0 by Sn2+. The Ni-Cu composite coating of 1-µm thickness has polycrystalline structure. And the electrical resistance of conductive Ni-Cu aramid fiber is 0.035 Ω/cm. The synthesis mechanism of the conductive aramid fiber with Ni-Cu composite coating is given.  相似文献   

19.
The Preparation of conductive biocomposite fiber through Carbon nanotubes (CNTs) incorporation into biopolymer matrixes has stimulated much interest for bio-implant applications. The present study focuses on development and characterization of biocomposite fiber composed of chitosan (CHT) as a biopolymer and multiwall carbon nanotubes (MWNTs) as a conductive filler. In term of processing, the most important challenge is to prepare a highly stable dispersion of MWNTs in biopolymer matrix. The hydrodynamic diameter distribution of CNTs in acetic acid solution acquired by dynamic light scattering (DLS).Results demonstrate the supreme stability of CNTs dispersion which is extremely essential for homogenous distribution of CNT in polymeric matrix. Rheological properties of the spinning solution have also been investigated to adjust the viscosity for fiber processing step. A range of viscosity between 2000–8000 cP, has been recorded in different CNT loading. The scanning electron microscopy (SEM) images of the surface and cross sectional area of the fibers reveal the formation of nano-pores after MWNT addition. The tensile strength show a maximum increase of about 33.65 % compared to bare CHT. Also, the measurement of four probe electrical conductivity for different MWNTs loading shows a maximum conductivity of 0.107 S/cm at percolation threshold of 2.89 wt%.  相似文献   

20.
Our aim in this study was to investigate the effects of course density, yarn linear density and thickness and type of conductive wire on electromagnetic shielding effectiveness. Metal/cotton conductive composite yarns were produced by the core-spun technique on the ring spinning machine, involving stainless steel, copper and silver coated copper wires with 40 μm, 50 μm, 60 μm thicknesses and Ne10/1 and Ne20/1 count yarns. The interlock fabrics were knitted on a 7G flat knitting machine with the three different machine settings. The EMSE and the surface resistivity of knitted fabrics were measured by the co-axial transmission line method according to the ASTM-D4935-10 standard in the frequency range from 15 to 3000 MHz and by the ASTM D257-07 standard, respectively. It was observed that all fabrics shielded around 95 % of electromagnetic waves at low frequencies, 80 % at medium frequencies and 70 % at high frequencies. Increasing the course density and thickness of conductive wire in interlock knitted fabrics increased the EMSE correspondingly. The knitted fabrics that had been produced with high yarn count showed greater EMSE because there was less isolation. The effect of the metal wire type was highly significant between 15 and 600 MHz.  相似文献   

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