查看更多>>摘要：Recently, the thermoelectric (TE) functions of Poly(3,4-ethylene-dioxythiophene):Poly(styrenesulphonate) (PEDOT:PSS) polymer have been extensively progressed, owing to its processability, flexibility, and its low intrinsic thermal conductivity. In this regards, nickel oxide (NiO) nano-particles have been mixed with PEDOT: PSS to design a new thermoelectric (PEDOT:PSS/NiO) system. The anisotropic (parallel // and vertical perpendicular to) TE functions as a function of the NiO content (10-40 wt%) have been investigated in the temperature range 300-390 K. The anisotropic conductivity (a) of the systems is reduced while their anisotropic Seebeck coefficients (S) have increased with the increase in the NiO content. The anisotropic conductivity of the systems is reduced while their anisotropic Seebeck coefficients have increased firstly and then decrease with the growth of temperature. The optimal PF//-24.61 +/- 0.3 mu W/mK2 and PF perpendicular to-3.40 +/- 0.03 mu W/mK2 are achieved at 340 K for 30 wt% with S//-39.07 +/- 1.7 mu V/K and S perpendicular to-27.34 +/- 2 mu V/K owing to the spin Seebeck coefficient, the reduction in the carrier concentration and the energy filtering effects. Interestingly, the impact of H2SO4 acid post-treatment on the PEDOT:PSS/NiO (30 wt%) has been done to obtain the highest PF values (PF//-54.59 +/- 1 mu W/mK2, PF perpendicular to-5.64 +/- 2 mu W/mK2) owing to the growth in the anisotropic a as a result of the removal of PSS polymers. Finally, the achieved PEDOT:PSS/NiO system offers a promising TE functions for potential applications in temperature sensors, wearable electronics and harvest technology.
Ozkazanc, ErselYegin, BaharGueven, Nimet CerenKadir, Er Doganhan...
11页
查看更多>>摘要：Poly(N-methylpyrrole) (PNMPy) and Poly(Pyrrole/N-methylpyrrole) P(Py/NMPy) copolymer were prepared in an aqueous solution by interfacial polymerization in the presence of surfactive dopant dodecylbenzene sulphonic acid (DBSA). Structural, thermal, morphological and dielectric characterization studies were performed by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fluorescence (FL), Thermogravimetric (TG), Scanning electron microscopy (SEM-EDS), Atomic Force Microscope (AFM), Brunauer-Emmett-Teller (BET) surface area and LCR meter analyses. The antimicrobial activity of the samples was investigated by the Agar diffusion method. Characterization studies showed that both PNMPy and P (Py/NMPy) were semi-crystalline in nature, depending on the arrangement of methyl groups in the polymer chains and/or the DBSA doping. Also, due to the interaction between DBSA and polymer chains, the samples showed a significant FL emission intensity. In the surface analyses, phases of polymer matrix and DBSA were clearly observed. Dielectric analyses showed that the charge transport mechanisms of both samples are highly compatible with the correlated barrier hopping (CBH) model. The activation energies required for the hopping of the charge carriers in the PNMPy and P(Py/NMPy) chains were calculated as 0.23 and 0.17 eV, respectively. In antibacterial tests against the various bacteria species, PNMPy formed an inhibition zone between 26 and 29 mm, while the copolymer formed an inhibition zone between 29 and 32 mm. The results showed that P(Py/NMPy) copolymer is a multifunctional material that is very suitable for electronic and photoelectric applications, as well as biomedical ones relating to antibacterial agents, infection-resistant medical devices and florescent antibiotic probe.
查看更多>>摘要：Polyaniline@carbon nanotube (PAni@CNT) hybrid with electrical conductivity of 5.2 S/cm was successfully prepared by inverted emulsion polymerization of aniline in the presence of CNT dispersed in toluene assisted by cetyl-trimethyl ammonium bromide (CTAB). Conductive composites based on poly (vinylidene fluoride-cohexafluoropropylene) (PVDFH) loaded with different amounts of PAni and PAni@CNT were prepared by dryblending the powders in a ball-mill followed by hot compression molding. This procedure resulted in a segregated structure of the fillers, as indicated by scanning electron microscopy (SEM). The composite with 10 wt% of PAni@CNT (9.5: 0.5 wt%) hybrid exhibited electrical conductivity near 10-3 S/m and outstanding electromagnetic wave (EMW) attenuation. Indeed, reflection loss (RL) of - 34 dB (more than 99.9% EMW attenuation) at 11.7 GHz and effective absorption bandwidth (EAB) frequency with RL < -10 dB (more than 90% EMW attenuation) corresponding to 7.3 GHz were observed for this composition with thickness of 3 mm. A comparative analysis of measured and calculated RL was conducted. Considering the simple and cost effective preparation procedure, these composites loaded with 5 wt% and 10 wt% of the hybrid material are promising alternatives for developing efficient microwave absorbing material for both military and civil applications.
查看更多>>摘要：We experimentally establish for the first time the influence of oxygen at carbon nanotube (CNT)-Cu interface on CNT/Cu composite electrical performances. We fabricated CNT/Cu films (CCF) with systematically varied oxygen interface characteristics through Cu electron beam deposition of CNT films functionalized by O3(g) exposure. By altering O3(g) exposure times (30-1000 s), different contents and types of interfacial O-functionalities (sp3C-O and sp2C--O) were obtained. CCF with optimal interfacial oxygen type and content showed enhanced CNT-Cu wetting and improvement in 4-probe electrical conductivities and their temperature stability. For e.g., Cu/CNT with interface sp3C-O and sp2C--O and O:C at% ratio-4.6 x 10-1 showed 1.6 x and 1.8 x higher electrical conductivity at room temperature and 110 C, respectively than composites with only sp3C-O interface and O:C at% ratio-2.7 x 10-1. Favorable effects of interfacial oxygen in previous literature have chiefly focused on CNT/Cu mechanical performances. Systematic studies on electrical performances vs. interfacial oxygen content and type are absent. Our results fill this knowledge-gap and provide experimental evidence on benefits of optimally tailored interfacial oxygen functionalities for enhancing Cu-nanotube interactions and composite electrical performances. We believe our work will add to existing CNT/Cu interface tailoring toolkits in literature, aiding fabrication and application-development of lightweight composites with rivaling performances.
查看更多>>摘要：Spontaneous orientation polarization (SOP) of amorphous organic semiconducting films has attracted much attention because of its frequent observation in common organic light-emitting diodes (OLEDs) and potential influences on the device properties of OLEDs. On the other hand, the formation mechanism of SOP has been controversial for a long time, ever since its discovery in 2002. Recently, the formation mechanism of SOP was explained in terms of the surface equilibration mechanism of vapor-deposited glasses, and the understanding of SOP has progressed significantly. Based on the improved understanding, some active control methods of SOP have been demonstrated and further influences on the device performance of OLEDs were revealed, suggesting that higher efficiency can be achieved by managing SOP properly. Furthermore, some applications of SOP have also been proposed, such as a self-assembled electret and a tool for evaluating materials properties. In this paper, recent progress in the understanding of SOP and its applications to devices are reviewed.
查看更多>>摘要：Multi-walled carbon nanotube-tungsten oxide (MWCNT-WO3) nanocomposites corresponding to different weight ratios of the two composite components MWCNT:WO3 were prepared by using a facile synthesis procedure and tested as photocatalysts activated by UV light for degradation of synthetic methylene blue (MB) solution. The composites were characterized by XRD, TEM, SEM, FTIR, UV-VIS, PL and TGA. The average crystallite size of WO3 calculated from XRD patterns was around 45 nm for all synthesized samples. TEM and SEM images confirmed the attachment of polyhedral WO3 nanoparticles on the MWCNTs surface. TGA results showed an enhanced thermal stability of the MWCNT-WO3 composites with increased content of WO3. Photocatalytic ex-periments proved that the use of MWCNTs offered a notable increase of the photocatalytic performance of WO(3 )in degradation of MB dye. The optimum MWCNT-W-7 composite exhibited 87 % MB degradation efficiency. The types of ROS generated by the composites were determined using EPR spectroscopy coupled with spin trapping technique. These results suggested that hydroxyl radicals were the main species involved in the photo-degradation process of MB dye.
查看更多>>摘要：Fibers made from carbon nanotubes (CNT) have received a lot of attention, including for the intended appli-cations in "artificial muscles ". Combination of CNT fibers with high capacitance particles such as carbide-derived carbon (CDC) is the focus of this research. A dielectrophoretic method was used to form novel CNT-CDC fibers with different wt% of CDC from 25% to 75%. The CNT-CDC fibers were compared to pristine CNT fibers in their electromechanical response to different electrochemical driving regimes (cyclic voltammetry, square wave po-tential steps) in an organic electrolyte. The best performance in strain and stress was achieved by CNT-CDC(50%) with nearly double charge density and 1.5 times higher electronic conductivity in comparison to pristine CNT fibers. The determination of the specific capacitance over chronopotentiometric measurements revealed 175 F g(-1) (0.54 A g(-1)) for CNT-CDC(75%) fibers, while the best stability and charging durability was shown by CNT-CDC(50%). The CNT-CDC fibers demonstrated consistent dual functionality for potential applications in linear actuators, supercapacitors or in multifunctional designs.
Ahmad, KhursheedKhan, Mohd QuasimAlsalme, AliKim, Haekyoung...
11页
查看更多>>摘要：Design and synthesis of metal-free, cost-effective, and ecofriendly nanostructured materials are of great importance for optoelectronic and electrochemical applications. In this study, we have synthesized metal-free sulfur-doped graphitic-carbon nitride (S@g-C3N4) by poly-condensation process. The synthesized S@g-C3N4 was authenticated by various advanced characterization techniques. Further, glassy carbon electrode was modified with S@g-C3N4 which acted as hydrazine sensor. This developed hydrazine sensor exhibited excellent detection limit of 0.98 mu M with sensitivity of 1.81 mu A mu M(-1)cm(- 2). Furthermore, synthesized S@g-C3N4 was also explored as photo-catalyst for the generation of hydrogen (H-2) using photo-catalysis process. The S@g-C3N4 exhibited excellent hydrogen production of 6547 mu mol g(-1) which suggested presence of excellent catalytic properties in S@g-C3N4.
NSTL
Elsevier