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1.
Nanomaterials (Basel) ; 13(2)2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36677973

RESUMO

With the rapid development of nanotechnology, nanocomposites and nanostructures have attracted significant attention due to their unique physical and chemical properties and variable functionalities [...].

2.
Nanomaterials (Basel) ; 12(15)2022 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-35957116

RESUMO

Ordered and disordered mesoporous structures were synthesized by a self-assembly method using a mixture of phenolic resin and petroleum-based mesophase pitch as the starting materials, amphiphilic triblock copolymer F127 as a soft template, hydrochloric acid as a catalyst, and distilled water as a solvent. Then, mesoporous carbons were obtained via autoclave method at low temperature (60 °C) and then carbonization at a relatively low temperature (600 °C), respectively. X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM) analyses revealed that the porous carbons with a mesophase pitch content of approximately 10 wt% showed a highly ordered hexagonal mesostructure with a highly uniform pore size of ca. 5.0 nm. In addition, the mesoporous carbons prepared by self-assembly and low-temperature autoclave methods exhibited the amorphous or crystalline carbon structures with higher specific surface area (SSA) of 756 m2/s and pore volume of 0.63 cm3/g, depending on the synthesis method. As a result, mesoporous carbons having a high SSA were successfully prepared by changing the mixing ratio of mesophase pitch and phenolic resin. The electrochemical properties of as-obtained mesoporous carbon materials were investigated. Further, the OMC-meso-10 electrode delivered the maximum SC of about 241 F/g at an applied current density of 1 A/g, which was higher than those of the MC-10 (~104 F/g) and OMC-20 (~115 F/g).

3.
Chemosphere ; 301: 134790, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35504473

RESUMO

Hydrogen peroxide (H2O2) is widely used in various industries and biological fields. H2O2 rapidly contaminants with water resources and hence simple detection process is highly wanted in various fields. The present study was focused on the biosensing, antimicrobial and embryotoxicity of bioinspired chitosan nanoparticles (Cs NPs), selenium nanoparticles (Se NPs), chitosan/selenium nanocomposites (Cs/Se NCs), silver nanoparticles (Ag NPs) and chitosan/silver nanocomposites (Cs/Ag NCs) synthesized using the aqueous Cucurbita pepo Linn. leaves extract. The physico-chemical properties of as-synthesized nanomaterials were confirmed by various spectroscopic and microscopic techniques. Further, hydrogen peroxide (H2O2) sensing properties and their sensitivities were confirmed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) methods, in which Cs/Ag NCs showed pronounced sensing properties. In addition, the mode of antibacterial interaction results clearly demonstrated the effective inhibitory activity of as-prepared Ag NPs and Cs/Ag NCs against Gram negative pathogenic bacteria. The highest embryotoxicity was recorded at 0.19 µg/ml of Ag NPs and 1.56 µg/ml of Se NPs. Intriguingly, the embryo treated with Cs/Se NCs and Cs/Ag NCs significantly reduced the toxicity in the presence of Cs matrix. However, Cs/Se NCs did not show good response in H2O2 sensing than the Cs/Ag NCs, implying the biocompatibility of Cs/Ag NCs. Overall, the obtained results clearly suggest that Cs/Ag NCs could be suitable for dual applications such as for the detection of environmental pollutant biosensors and for biomedical research.


Assuntos
Quitosana , Nanopartículas Metálicas , Nanocompostos , Selênio , Antibacterianos/química , Quitosana/química , Peróxido de Hidrogênio , Nanopartículas Metálicas/química , Nanopartículas Metálicas/toxicidade , Nanocompostos/química , Nanocompostos/toxicidade , Selênio/farmacologia , Prata/química
4.
Nanomaterials (Basel) ; 11(9)2021 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-34578763

RESUMO

In this work, we prepared network-structured carbon nanofibers using polyacrylonitrile blends (PAN150 and PAN85) with different molecular weights (150,000 and 85,000 g mol-1) as precursors through electrospinning/hot-pressing methods and stabilization/carbonization processes. The obtained PAN150/PAN85 polymer nanofibers (PNFs; PNF-73, PNF-64 and PNF-55) with different weight ratios of 70/30, 60/40 and 50/50 (w/w) provided good mechanical and electrochemical properties due to the formation of physically bonded network structures between the blended PAN nanofibers during the hot-processing/stabilization processes. The resulting carbonized PNFs (cPNFs; cPNF-73, cPNF-64, and cPNF-55) were utilized as anode materials for supercapacitor applications. cPNF-73 exhibited a good specific capacitance of 689 F g-1 at 1 A g-1 in a three-electrode set-up compared to cPNF-64 (588 F g-1 at 1 A g-1) and cPNF-55 (343 F g-1 at 1 A g-1). In addition, an asymmetric hybrid cPNF-73//NiCo2O4 supercapacitor device also showed a good specific capacitance of 428 F g-1 at 1 A g-1 compared to cPNF-64 (400 F g-1 at 1 A g-1) and cPNF-55 (315 F g-1 at 1 A g-1). The cPNF-73-based device showed a good energy density of 1.74 W h kg-1 (0.38 W kg-1) as well as an excellent cyclic stability (83%) even after 2000 continuous charge-discharge cycles at a current density of 2 A g-1.

5.
ACS Appl Mater Interfaces ; 13(15): 17487-17500, 2021 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-33844490

RESUMO

The scrupulous designation of hollow and porous electroactive materials incorporating prolific redox-active polyphase transition-metal oxide decorated with polyphase transition-metal sulfide onto rGO (reduced graphene oxide)-supported conductive substrate has never been an easy task due to the very good coordination affair of sulfur toward transition metals. Herein, cost-effective hydrothermal growth followed by a metal-organic framework (MOF)-mediated sulfidation approach is employed to achieve burl-like Ni-Co-S nanomaterial-integrated hollow and porous NiMoO4 nanotubes onto rGO-coated Ni foam (rGO-NiMoO4@Ni-Co-S) as the electrode material for supercapacitors. The open framework of the rGO-Co-MOF template after the etching and sulfidation process not only enables the creation of a tubular structure of NiMoO4 nanorods but also provides convenient ion-electron pathways to promote rapid faradic reactions for the hybrid composite electrode. Owing to the unique hollow and tubular structure, the as-fabricated rGO-NiMoO4@Ni-Co-S electrode exhibits a high specific capacity of 318 mA h g-1 at 1 A g-1 and remarkable cyclic performance of 88.87% after 10,000 consecutive charge-discharge cycles in an aqueous 2 M KOH electrolyte on a three-electrode configuration. Moreover, the assembled rGO-NiMoO4@Ni-Co-S//rGO-MDC (MOF-derived carbon) asymmetric supercapacitor device exhibits a satisfactory energy density of 57.24 W h kg-1 at a power density of 801.8 W kg-1 with an admirable life span of 90.89% after 10,000 repeated cycles.

6.
Molecules ; 25(24)2020 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-33322446

RESUMO

In this work, we report the carbon fiber-based wire-type asymmetric supercapacitors (ASCs). The highly conductive carbon fibers were prepared by the carbonized and graphitized process using the polyimide (PI) as a carbon fiber precursor. To assemble the ASC device, the CoMnO2-coated and Fe2O3-coated carbon fibers were used as the cathode and the anode materials, respectively. Herein, the nanostructured CoMnO2 were directly deposited onto carbon fibers by a chemical oxidation route without high temperature treatment in presence of ammonium persulfate (APS) as an oxidizing agent. FE-SEM analysis confirmed that the CoMnO2-coated carbon fiber electrode exhibited the porous hierarchical interconnected nanosheet structures, depending on the added amount of APS, and Fe2O3-coated carbon fiber electrode showed a uniform distribution of porous Fe2O3 nanorods over the surface of carbon fibers. The electrochemical properties of the CoMnO2-coated carbon fiber with the concentration of 6 mmol APS presented the enhanced electrochemical activity, probably due to its porous morphologies and good conductivity. Further, to reduce the interfacial contact resistance as well as improve the adhesion between transition metal nanostructures and carbon fibers, the carbon fibers were pre-coated with the Ni layer as a seed layer using an electrochemical deposition method. The fabricated ASC device delivered a specific capacitance of 221 F g-1 at 0.7 A g-1 and good rate capability of 34.8% at 4.9 A g-1. Moreover, the wire-type device displayed the superior energy density of 60.2 Wh kg-1 at a power density of 490 W kg-1 and excellent capacitance retention of 95% up to 3000 charge/discharge cycles.


Assuntos
Fibra de Carbono/química , Cobalto/química , Imidas/química , Compostos de Manganês/química , Óxidos/química , Carbono/química , Capacitância Elétrica , Condutividade Elétrica , Eletroquímica/métodos , Eletrodos , Metais , Microscopia Eletrônica de Varredura , Nanoestruturas/química , Nanotubos , Níquel , Oxirredução , Porosidade
7.
J Nanosci Nanotechnol ; 20(11): 6862-6870, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-32604528

RESUMO

The mechanical properties and damping behavior of carbon fiber-reinforced plastic composites with functionalized multi-walled carbon nanotubes were examined. The functionalized multi-walled carbon nanotubes were blended with epoxy resins to prepare multi-walled carbon nanotubes/carbon fiber-reinforced plastic composites. The dispersion properties of functionalized multi-walled carbon nanotubes in epoxy resins were examined using surface free energy. The mechanical properties of functionalized multi-walled carbon nanotubes/carbon fiber-reinforced plastic composites were measured by interlaminar shear strength and torsion strength. The functionalized multi-walled carbon nanotubes/carbon fiber-reinforced plastic composites had superior mechanical properties due to the increase in dispersion properties of functionalized multi-walled carbon nanotubes in epoxy resins. However, the tan delta values of damping behavior, analyzed by dynamic mechanical analysis, varied with the type of functional groups of functionalized multi-walled carbon nanotubes. The composites obtained from functionalized multi-walled carbon nanotubes obtained through spermidine amidation reaction and carbon fiber-reinforced plastic showed excellent tan delta values due to the flexible segments in side chains.

8.
J Colloid Interface Sci ; 564: 65-76, 2020 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-31901835

RESUMO

In this study, mesoporous nickel cobaltite (NiCo2O4) nanorods as electrode materials for high-performance hybrid supercapacitor were fabricated onto Ni foam by a simple and cost effective oxalic acid (OA) assisted rapid co-precipitation method. The effects of different metal precursors (NCO-Nitrate, NCO-Chloride and NCO-Acetate) on the electrochemical capacitive properties were studied. FE-SEM analysis confirmed that all samples exhibited highly dense mesoporous NiCo2O4 nanorods vertically grown on the surface of Ni foam with excess accessible surfaces and unique sizes and morphologies. The resultant NiCo2O4 nanorod electrodes (for NCO-Nitrate, NCO-Chloride and NCO-Acetate) delivered the maximum specific capacitances of 790, 784, 776 F g-1 at the current density of 1 A g-1 with ultra-high capacitance retention of 82.27, 81.63 and 81.71% even at 20 A g-1 and excellent cyclic stability of 84.25, 83.33 and 83.24% capacitance retention at 5 A g-1 after 5000 cycles. The asymmetric supercapacitor (ASC) device was also sandwiched by using NCO-Nitrate as positive electrode and N-doped graphene hydrogel (NGH) as negative electrode. The fabricated ASC device delivered superior energy density (42.5 W h kg-1) at high power density (746.34 W kg-1) with excellent long cyclic stability (90% initial capacitance retention after 5000 cycles at 5 A g-1).

9.
Sci Rep ; 8(1): 11517, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30069032

RESUMO

The nylon 6 nanofiber-reinforced cellulose acetate (NF-r-CA) film as a fiber-based transparent substrate is used to develop the highly transparent electrodes with excellent durable and extremely foldable properties. Mechanical properties of the NF-r-CA films are greatly improved, suggesting that the nanofibers provide an effective reinforcement. The NF-r-CA transparent films show smooth surface morphologies (RRMS ~ 27 nm) than as-spun nylon 6 nanofiber membrane, indicating the successful infiltration of cellulose acetate into the voids of nylon nanofiber membranes. The NF45-r-CA electrodes prepared using AgNWs concentration of 0.025 wt% and electrospinning time of 45 min are highly transparent (~90%), lower sheet resistance (~24 Ω sq-1) and mechanically robust (59.7 MPa). The sheet resistance of NF45-r-CA electrodes remains almost constant, and the change ratio is less than 0.01% even after a repeated bending test of 10,000 cycles (bending radius ~1 mm), whereas ITO electrode shows gradual increase in sheet resistance and then eventually no electrical signal at about 270 cycles. We also demonstrate the successful fabrication of the foldable polymer-disperse liquid crystal film utilizing highly transparent NF45-r-CA electrode, which shows outstanding working stability after bending test of 500 cycles at an extreme bending radius of 1.5 mm.

10.
Nanoscale ; 9(47): 18819-18834, 2017 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-29177332

RESUMO

Wire type supercapacitors with high energy and power densities have generated considerable interest in wearable applications. Herein, we report a novel NiCo2S4-decorated 3D, porous Ni film@Ni wire electrode for high performance supercapacitor application. In this work, a facile method is introduced to fabricate a 3D, porous Ni film deposited on a Ni wire as a flexible electrode, followed by decoration with NiCo2S4 as an electroactive material. The fabricated NiCo2S4-decorated 3D, porous Ni film@Ni wire electrode displays a superior performance with an areal and volumetric capacitance of 1.228 F cm-2 and 199.74 F cm-3, respectively, at a current density of 0.2 mA cm-1 with a maximum volumetric energy and power density (EV: 6.935 mW h cm-3; PV: 1.019 W cm-3). Finally, the solid state asymmetric wire type supercapacitor is fabricated using the fabricated NiCo2S4-decorated 3D, porous Ni film@Ni wire as a positive electrode and N-doped reduced graphene oxide (N-rGO) as a negative electrode and this exhibits good areal and volumetric capacitances of CA: 0.12 F cm-2 and CV: 19.57 F cm-2 with a higher rate capability (92%). This asymmetric wire type supercapacitor demonstrates a low leakage current and self-discharge with a maximum volumetric energy (EV: 5.33 mW h cm-3) and power (PV: 855.69 mW cm-3) density.

11.
Carbohydr Polym ; 163: 153-161, 2017 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-28267492

RESUMO

In this study, we present a highly efficient and economical solution called as 'in situ hydrogenation' for preparation of highly conductive thin film electrode based on silver nanodendrites. The silver nanodendrite (AgND)/cellulose acetate (CA) thin film electrodes exhibited sheet resistance ranging from 0.32ohm/sq to 122.1ohm/sq which could be controlled by changing the concentration of both silver and polymer. In addition, these electrodes exhibited outstanding toughness during the bending test. Further, these thin film electrodes have great potential for scale-up with an average weight of 3mg/cm2 and can be also combined with active nanomaterials such as multiwalled carbon nanotubes (MWCNTs) to fabricate AgND/CA/MWCNTs thin film for high-performance flexible supercapacitor electrode. The AgND/CA/MWCNTs electrodes exhibited a maximum specific capacitance of 237F/g at a current density of 0.3A/g. After 1000 cycles, the AgND/MWCNT/CA exhibited a decrease of 16.0% of specific capacitance.

12.
J Nanosci Nanotechnol ; 16(4): 4080-5, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27451768

RESUMO

We report the hierarchically assembled nanofibers created by LbL self-assembly depending on the PSS-PAA fraction in the blend solutions and pH during bulid-up of the PAH/(PSS-PAA) multilayer films. The multilayer [(PEI/blend)/(PAH/blend)4] films with ρPAA (PSS-PAA fraction in the blend solutions) = 0.0 in the blend solution exhibited surface morphologies of randomly isolated globular clusters, while at ρPAA = 0.75, worm-like morphologies were observed. Interestingly, the multilayer [(PEI/blend)/(PAH/blend)4 films with ρPAA = 0.9 exhibited unique fibrous morphologies with the diameter of about 50 nm at narrower pH range from 3.5 to 4.2, but also the fiber diameter distribution was narrower. Based on the thickness from the X-ray reflectivity, the thickness of the one bilayer multilayer film seemed to be 8.6 nm. The 3 bilayers multilayer film seemed to be formed as islands with very large roughness. The crystal sizes of the 3 bilayers and 5 bilayers multilayer films were about 71 nm and 123 nm, respectively. The resultant films were characterized using atomic force microscopy (AFM) and real-time in situ X-ray scattering measurements.

13.
Sci Rep ; 6: 20313, 2016 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-26828633

RESUMO

The design and development of an economic and highly active non-precious electrocatalyst for methanol electrooxidation is challenging due to expensiveness of the precursors as well as processes and non-ecofriendliness. In this study, a facile preparation of core-shell-like NiCo2O4 decorated MWCNTs based on a dry synthesis technique was proposed. The synthesized NiCo2O4/MWCNTs were characterized by infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and selected area energy dispersive spectrum. The bimetal oxide nanoparticles with an average size of 6 ± 2 nm were homogeneously distributed onto the surface of the MWCNTs to form a core-shell-like nanostructure. The NiCo2O4/MWCNTs exhibited excellent electrocatalytic activity for the oxidation of methanol in an alkaline solution. The NiCo2O4/MWCNTs exhibited remarkably higher current density of 327 mA/cm(2) and a lower onset potential of 0.128 V in 1.0 M KOH with as high as 5.0 M methanol. The impressive electrocatalytic activity of the NiCo2O4/MWCNTs is promising for development of direct methanol fuel cell based on non-Pt catalysts.

14.
PLoS One ; 10(10): e0139303, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26468641

RESUMO

Biocontamination within the international space station is ever increasing mainly due to human activity. Control of microorganisms such as fungi and bacteria are important to maintain the well-being of the astronauts during long-term stay in space since the immune functions of astronauts are compromised under microgravity. For the first time control of the growth of an opportunistic pathogen, Aspergillus niger, under microgravity is studied in the presence of α-aminophosphonate chitosan. A low-shear modelled microgravity was used to mimic the conditions similar to space. The results indicated that the α-aminophosphonate chitosan inhibited the fungal growth significantly under microgravity. In addition, the inhibition mechanism of the modified chitosan was studied by UV-Visible spectroscopy and cyclic voltammetry. This work highlighted the role of a bio-based chitosan derivative to act as a disinfectant in space stations to remove fungal contaminants.


Assuntos
Antifúngicos/química , Antifúngicos/farmacologia , Aspergillus niger/efeitos dos fármacos , Quitosana/análogos & derivados , Quitosana/química , Organofosfonatos/química , Organofosfonatos/farmacologia , Ausência de Peso/efeitos adversos , Antifúngicos/síntese química , Quitosana/síntese química , Quitosana/farmacologia , Hifas/efeitos dos fármacos , Organofosfonatos/síntese química , Astronave
15.
Mater Sci Eng C Mater Biol Appl ; 55: 88-94, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26117742

RESUMO

Biocompatible keratin-based hydrogels prepared by electron beam irradiation (EBI) were examined in wound healing. As the EBI dose increased to 60 kGy, the tensile strength of the hydrogels increased, while the percentage of elongation of the hydrogels decreased. After 7 days, the dehydrated wool-based hydrogels show the highest mechanical properties (the % elongation of 1341 and the tensile strength of 6030 g/cm(2) at an EBI dose of 30 kGy). Excision wound models were used to evaluate the effects of human hair-based hydrogels and wool-based hydrogels on various phases of healing. On post-wounding days 7 and 14, wounds treated with either human hair-based or wool-based hydrogels were greatly reduced in size compared to wounds that received other treatments, although the hydrocolloid wound dressing-treated wound also showed a pronounced reduction in size compared to an open wound as measured by a histological assay. On the 14th postoperative day, the cellular appearances were similar in the hydrocolloid wound dressing and wool-based hydrogel-treated wounds, and collagen fibers were substituted with fibroblasts and mixed with fibroblasts in the dermis. Furthermore, the wound treated with a human hair-based hydrogel showed almost complete epithelial regeneration, with the maturation of immature connective tissue and hair follicles and formation of a sebaceous gland.


Assuntos
Materiais Biocompatíveis/farmacologia , Hidrogéis/farmacologia , Queratinas/farmacologia , Cicatrização/efeitos dos fármacos , Animais , Bandagens , Colágeno/efeitos dos fármacos , Derme/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Folículo Piloso/efeitos dos fármacos , Humanos , Pele/efeitos dos fármacos , Resistência à Tração , Lã/efeitos dos fármacos
16.
ACS Appl Mater Interfaces ; 7(19): 10365-73, 2015 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-25923689

RESUMO

Controlled growth of nanometer-scale multilayered coatings of negatively charged sulfonated poly(benzobisimidazole) (SPBI), complexed with positively charged poly(2-vinylpyridine) (P2VP) on quartz, and Nafion membrane as substrates has been explored. Both polymers, SPBI and P2VP, possess a net charge in methanol as a result of the dissolution of SPBI by complexation with triethylamine (TEA) and the protonation of P2VP with HCl, respectively, and thereby can form a multilayered molecular composite of alternating anionic SPBI and cationic P2VP via an electrostatic layer-by-layer (LbL) self-assembly. UV-vis absorption spectrophotometry was used to monitor the buildup and growth rate of such SPBI/P2VP multilayer films. Atomic force microscopy (AFM) was used to determine the roughness and thickness of the resulting SPBI/P2VP multilayers. As a result, it was found that a steady-state linear growth regime for the LbL self-assembled SPBI/P2VP multilayer films and coatings onto quartz and Nafion membranes was observed after completion of the first few deposition cycles, indicating the successful formation of the SPBI/P2VP multilayered assembly in methanol solutions. In addition, the SPBI/P2VP multilayer films in the perpendicular direction (flat view) demonstrated isotropic orientation distribution on the Nafion membrane, while the SPBI/P2VP multilayer films examined by X-ray scattering in the parallel direction (edge view) revealed anisotropic orientation, the combined observations indicating confinement of SPBI rods to the plane of the coating. We further found that the SPBI/P2VP multilayer coated Nafion possesses good thermal stability, as indicated by isothermal gravimetric analysis at 310 °C, and it was further observed that SPBI/P2VP multilayer coatings using the LbL self-assembly technique on Nafion membrane significantly increased the membrane stiffness, despite the small coating thickness employed.

17.
Carbohydr Polym ; 117: 408-413, 2015 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-25498653

RESUMO

A new spicule-like cellulose nanostructure is prepared from electrospun cellulose nanofibers using a one-pot bifunctional catalysis strategy namely hydrolytic hydrogenation. The electrospun cellulose nanofibers or cellulose film was treated in presence of catalyst consisting of an alkali and a metal to produce celluloses with structures like nanospicules, nanoflowers or nanorods, respectively. This work highlights the promising combination of electrospinning and hydrolysis/hydrogenation for facile production of hierarchical cellulose nanostructures such as nanospicules and nanorods.

18.
Mater Sci Eng C Mater Biol Appl ; 33(8): 5051-7, 2013 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-24094223

RESUMO

The biocompatible and highly porous keratin-based hydrogels were prepared using electron beam irradiation (EBI). The conditions for keratin-based hydrogel formation were investigated depending on several conditions, including the presence of poly(vinyl alcohol) (PVA), concentration of keratin solution, EBI dose, and poly(ethylene imine) (PEI) additives. The pure keratin (human hair and wool) aqueous solution was not gelled by EBI, while the aqueous keratin solutions blended with PVA were gelled at an EBI dose of more than 90 kGy. Furthermore, in the presence of PEI, the aqueous keratin solution blended with PVA could be gelled at a considerably lower EBI dose, even at 10 kGy. This finding suggests that the PEI additives significantly influence the rate of gelation and that PEIs function as an accelerator during gelation. The resulting keratin-based hydrogels were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), gel fraction, degree of swelling, gel strength, and kinetics of swelling analyses.


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Queratinas/química , Radiação Ionizante , Animais , Elétrons , Cabelo/metabolismo , Humanos , Iminas/química , Microscopia Eletrônica de Varredura , Polietilenos/química , Álcool de Polivinil/química , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à Tração , Água/química , Lã/metabolismo
19.
J Nanosci Nanotechnol ; 13(3): 1759-64, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23755586

RESUMO

We report the mechanical property and electromagnetic interference shielding effectiveness (EMI SE) of poly(vinyl alcohol) (PVA)/graphene and PVA/multi-walled carbon nanotube (MWCNT) composite nanofibers prepared by electrospinning. The metal (Cu) was deposited on the resultant PVA composite nanofibers using metal deposition technique in order to improve the mechanical properties and EMI shielding properties. The resulting PVA composite nanofibers and Cu-deposited corresponding nanofibers were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and wide angle X-ray diffraction (WAXD). Tensile tests were performed on the PVA/graphene and PVA/MWCNT composite nanofibers. The tensile strength of the PVA/graphene and PVA/MWCNT composite nanofibers was found to be 19.2 +/- 0.3 MPa at graphene content - 6.0 wt% and 12.2 +/- 0.2 MPa at MWCNT content - 3.0 wt%, respectively. The EMI SE of the Cu-deposited PVA/graphene composite nanofibers was significantly improved compared to pure PVA/graphene composite nanofibers, and also depended on the thickness of Cu metal layer deposited on the PVA composite nanofibers.

20.
J Mater Sci Mater Med ; 24(8): 2029-36, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23661256

RESUMO

In this work, novel poly(ε-caprolactone) (PCL) fibrous membranes incorporating amphiphilic polyhedral oligosilsesquioxane (POSS) telechelic (PEG-POSS telechelic) were prepared via electrospinning. The unique microstructure, morphology, thermal stability of the resulting PCL/PEG-POSS telechelic electrospun nanowebs were investigated by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis, respectively. The addition of amphiphilic PEG-POSS telechelic strongly influenced the fiber diameters, microstructures of the resultant PCL/PEG-POSS telechelic nanofibers, compared to pure PCL nanofibers. The potential biomedical applications of such PEG-POSS telechelic nanowebs as a scaffolding material were also evaluated in vitro using mouse osteoblast-like MC3T3-E1 cells. The cell adhesion, spreading, and interaction behavior of pure PCL and PCL/PEG-POSS telechelic fibrous membranes were explored. It was found that electrospun PCL fibrous membranes incorporating amphiphilic PEG-POSS telechelic showed higher initial cell attachment than pure PCL due to the higher surface free energy of POSS siloxanes. Moreover, the obtained PCL/PEG-POSS telechelic fibrous scaffolds were found to be nontoxic and to maintain the good adhesion ratio between cells and surface (about ~93 %) after cell culturing for 24 h.


Assuntos
Compostos de Organossilício/química , Osteoblastos/citologia , Poliésteres/química , Polietilenoglicóis/química , Alicerces Teciduais , Animais , Adesão Celular/efeitos dos fármacos , Técnicas de Cultura de Células/instrumentação , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Galvanoplastia/métodos , Camundongos , Compostos de Organossilício/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/fisiologia , Poliésteres/síntese química , Polietilenoglicóis/farmacologia , Tensoativos/química , Tensoativos/farmacologia , Alicerces Teciduais/química , Difração de Raios X
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