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Manipulation and Deposition of Complex, Functional Block Copolymer Nanostructures using Optical Tweezers
摘要： Block copolymer self-assembly has enabled the creation of a range of solution-phase nanostructures with applications from optoelectronics and biomedicine to catalysis. However, to incorporate such materials into devices a method that facilitates their precise manipulation and deposition is desirable. Herein we describe how optical tweezers can be used to trap, manipulate, and pattern individual cylindrical micelles and larger hybrid micellar materials. Through the combination of TIRF imaging and optical trapping we can precisely control the three-dimensional motion of individual cylindrical block copolymer micelles in solution, enabling the creation of customizable arrays. We also demonstrate that dynamic holographic assembly enables the creation of ordered customizable arrays of complex hybrid block copolymer structures. By creating a program which automatically identifies, traps and then deposits multiple assemblies simultaneously we have been able to dramatically speed up this normally slow process, enabling the fabrication of arrays of hybrid structures containing hundreds of assemblies in minutes rather than hours.
关键词： optical trapping,directed assembly,block copolymers,self-assembly,nanofibers
更新于2025-11-21 11:24:58
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Effect of incorporation of sulphur on the structural, morphological and optical studies of CdSe thin films deposited by solution processed spin coating technique
摘要： Ternary compound semiconductor CdSexS1-x (x = 1, 0.8, 0.6, 0.4, 0.2 and 0) thin films were prepared on glass substrates by using simple solution processed spin coating technique. Cadmium acetate, sodium selenosulfate and thiourea were used as source materials for Cd2+, Se2? and S2? ions, while triethanolamine was used as a capping agent. The 25% concentred NH4OH solution was used as a complex reagent and also used to adjust the pH of the final solution ~ 11. The deposition conditions (rotation speed 2000 rpm for 30 s and substrate dried in the air at 120 °C for 2 min) were remain same for all the samples. The as-deposited thin films on glass substrate were annealed at 350 °C for 30 min. The X-ray diffraction pattern shows that all the samples were polycrystalline in the nature with hexagonal structure. The most of prepared thin films were highly textured along (002) plane and peak position for plane (002) is shifted with change in composition ‘x’. The average crystallite size in CdSexS1-x thin films were found between 62.6 nm to 93.4 nm. Scanning electron microscopy images showed uniform deposition morphology with spherical shaped grains distributed over entire glass substrate. Samples CdSe0.8S0.2 and CdSe0.6S0.4 thin films indicated interesting morphological features with the combination of spherical shaped nanoparticles and interconnected nanofibers which form hierarchical flowerlike micro-structure. Energy dispersive X-Ray studies confirmed that thin films were having approximately same stoichiometry of atomic ratio of elements Cd, Se and S as present in volumetric ratio of the reactants in chemical solution. Fourier transform infrared studies confirmed the formation of the Cd(Se,S) bonding in materials. The optical band gap of CdSexS1-x thin films were found as direct band gap in the range of 1.82 eV to 2.32 eV. As the incorporation of sulphur element increases, the band gap of CdSexS1-x thin film also increases. The CdSexS1-x thin films can be used as absorption layer in solar photovoltaic cell which is due to wide and fine tenability of the energy band gap.
关键词： Nanofibers,Spin coating,Absorption layer,cadmium sulfide,Cadmium selenide,Hierarchical flowerlike microstructure,Ternary compound semiconductor
更新于2025-11-21 11:18:25
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Micropatterning MoS2/Polyamide Electrospun Nanofibrous Membranes Using Femtosecond Laser Pulses
摘要： The capability of modifying and patterning the surface of polymer and composite materials is of high significance for various biomedical and electronics applications. For example, the use of femtosecond (fs) laser ablation for micropatterning electrospun nanofiber scaffolds can be successfully employed to fabricate complex polymeric biomedical devices, including scaffolds. Here we investigated fs-laser ablation as a flexible and convenient method for micropatterning polyamide (PA6) electrospun nanofibers that were modified with molybdenum disulfide (MoS2). We studied the influence of the laser pulse energy and scanning speed on the topography of electrospun composite nanofibers, as well as the irradiated areas via scanning electron microscopy and spectroscopic techniques. The results showed that using the optimal fs-laser parameters, micropores were formed on the electrospun nanofibrous membranes with size scale control, while the nature of the nanofibers was preserved. MoS2-modified PA6 nanofibrous membranes showed good photoluminescence properties, even after fs-laser microstructuring. The results presented here demonstrated potential application in optoelectronic devices. In addition, the application of this technique has a great deal of potential in the biomedical field, such as in tissue engineering.
关键词： femtosecond laser,micromachining,composite nanofibers,electrospinning,MoS2
更新于2025-11-21 11:08:12
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Influence of Non-Toxic Magnetic Cellulose Nanofibers on Chitosan based Edible Nanocoating: A Candidate for Improved Mechanical, Thermal, Optical, and Texture Properties
摘要： The present work demonstrates the formulation of cellulose nanofiber (CNF) or magnetic cellulose nanofiber (mgCNF) dispersed chitosan based edible nanocoating with superior mechanical, thermal, optical and texture properties. The fabrication of mgCNF is successfully achieved through single-step co-precipitation route, where iron particles get adsorbed onto CNF. The thermal stability of mgCNF is improved considerably, where ~17% reduction in weight is observed, whereas CNF degrades completely under identical conditions. TGA analysis shows that there is an improvement in thermal stability for both CNF and mgCNF reinforced CS nanocoatings, where mgCNF provides more heat dimensional stability than CNF dispersed CS nanocoatings. Further, the edible nanocoatings are stable even at the temperature of heat treatment such as food sterilization. The mechanical property of the mgCNF dispersed chitosan (CS) shows remarkable improvement in tensile strength (57.86±14 MPa) and Young’s modulus (2348.52±276 MPa) compared to neat CS (6.27±0.7 MPa and 462.36±64 MPa, respectively). To recognize the developed materials as safe as food, the quantification of iron is made by using ICP-MS technique. It is noteworthy to mention that mgCNF coated CS help in improving the texture of cut pineapples in comparison with uncoated pineapple slices at ambient condition.
关键词： chitosan,magnetic cellulose nanofibers,cellulose nanofiber,edible nanocoating,packaging property
更新于2025-11-21 11:01:37
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Mg Doped Perovskite LaNiO <sub/>3</sub> Nanofibers as an Efficient Bifunctional Catalyst for Rechargeable Zinc–Air Batteries
摘要： Rational design of efficient and durable bifunctional catalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is important for rechargeable zinc-air batteries. Herein, Mg doped perovskite LaNiO3 (LNO) nanofibers (LNMO NFs) were prepared by a facile electrospinning method combined with subsequent calcination. LNMO NFs show a more positive half-wave potential of 0.69V and a lower overpotential of 0.45 V at a current density of 10 mA cm-2 than those of the pristine LNO NFs. As an air electrode for zinc-air battery, the cell with LaNi0.85Mg0.15O3 NFs catalyst is able to deliver a high specific capacity of 809.9 mAh g-1 at a current density of 5 mA cm-2. It also shows an excellent cycling stability over 110 h at a current density of 10 mA cm?2. DFT calculation results demonstrate that the LNMO surface binds oxygen stronger than LNO, which contributes to enhanced OER activity as observed in our experiments. The results indicate that LNMO NFs is an efficient and durable bifunctional catalyst for zinc-air batteries.
关键词： bi-functional catalyst,Mg doped LaNiO3 nanofibers,electrospinning,density functional theory calculation,zinc-air batteries
更新于2025-11-14 17:04:02
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CePd‐Nanoparticles‐Incorporated Carbon Nanofibers as Efficient Counter Electrode for DSSCs
摘要： In this study, the cerium-palladium (CePd) incorporated carbon nanofibers (CNFs) were manufactured by low-cost and versatile electrospinning technique and successfully applied as a counter electrode to fabricate the dye-sensitized solar cells (DSSCs). The utilized physiochemical techniques, X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscope (FESEM), and transmission electron microscope (TEM) confirmed the formation of carbon nanofibers (CNFs) incorporated by Ce and Pd nanoparticles. CePd incorporated CNFs were preliminary presented good electrocatalytic activity towards the iodide redox couple, as investigated by cyclic voltammetry. The DSSC fabricated using CePd incorporated CNFs based counter electrode (CE) attained an applicable power conversion efficiency (PCE) of 4.52% along with open circuit voltage (VOC) of 0.739 V, a short-circuit current density (JSC) of 11.42 mA/cm2 and fill factor (FF) of 0.54. According to primary results, the CePd incorporated CNFs based CE is a promising, and cost-effective alternative CE for photoelectrochemical devices.
关键词： Alloys nanoparticles,Solar cells,Electrocatalyst,Cyclic voltammetry,Carbon nanofibers
更新于2025-09-23 15:23:52
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Carbon Allotropes: Metal-Complex Chemistry, Properties and Applications || Classic Carbon Nanostructures
摘要： The era of carbon-based nanotechnology, as it is well-known, started from 1985 when the fullerene C60 was discovered. The rediscovery of carbon nanotubes and unexpected discovery of graphene gave a powerful impulse to the further development of carbon nanostructures. At present, these nanocarbons, as well as nanodiamonds or nanofibers, can already be considered as 'conventional' carbon nanostructures.
关键词： nanofibers,nanodiamonds,carbon nanotubes,graphene,carbon nanostructures,fullerenes
更新于2025-09-23 15:23:52
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Nanomechanical, Mechanical Responses and Characterization of Piezoelectric Nanoparticle-Modified Electrospun PVDF Nanofibrous Films
摘要： Limitless implementations of nanofibrous membrane show the importance of understanding the nanomechanical responses for water purification and piezoelectric nanogenerator applications. Here, the polyvinylidene fluoride (PVDF) electrospun nanofibrous films doped by 0.01, 0.05 and 0.1 wt% of ZnO nanoparticles were prepared in the method of electrospinning. Characterizations of PVDF nanocomposite fibrous films were inspected using field emission scanning electron microscope, thermogravimetric analysis, water contact angle, uniaxial tensile test and nanoindentation technique. The influence of minimal concentration of piezoelectric nanoparticles on the morphological, water contact angle, dynamic water contact angle, piezoelectric, thermal and mechanical stabilities of nanocomposite fibrous films was examined. The nanoscale mechanical properties of the PVDF/ZnO nanofibrous films were performed by nanoindentation technique at different spots of nanofibrous mat to examine the elastic–plastic behavior of membranes. The eventual ZnO nanoparticle-modified nanofibrous membranes have been shown nano-level fibers, considerable hydrophilicity and preferable thermal, mechanical and piezoelectric properties. The doping of polymer by 0.1 wt% of ZnO nanoparticles exposed significant enhancement of thermal, mechanical and nanomechanical responses of the melting temperature 2% (170–173 °C), tensile strength 20% (2.418 MPa), elastic modulus 18% (2.418 GPa) and hardness 60% (235 MPa) and piezoelectric coefficient 13.42 pC/N of the nanofibrous films. These understandings of nanoscale properties are highly promising in the development of sensor and actuators, biomedical, energy harvesting and water filtration devices.
关键词： Thin films,Nanomechanical responses,Nanofibers,PVDF,Piezoelectric nanoparticles,Electrospinning
更新于2025-09-23 15:23:52
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Noninvasive biodegradable nanoparticles-in-nanofibers single-dose ocular insert: <i>in vitro</i> , <i>ex vivo</i> and <i>in vivo</i> evaluation
摘要： Aim: This study involves, for the first time, the development of mucoadhesive biodegradable polymeric-multilayered nanoparticles-in-nanofibers (NPs-in-NFs) matrix as an innovative single-dose noninvasive ocular-insert that could substitute conventional ocular dosage-forms. Materials & methods: Azithromycin-loaded poly(lactic-co-glycolic acid) copolymer/pluronic NPs were developed then incorporated into electrospun polyvinylpyrrolidone NFs, and tested for their efficient treatment of ocular bacterial infection. Results: Release and permeation studies proved the ability of the insert to control drug release over 10 days. Conclusion: The incorporation of NPs into NFs achieved several other benefits like increasing ocular residence and contact time with conjunctival tissue, accurate dose delivery, sustaining drug release with constant rate, reducing frequency of administration, improving bioavailability along with decreasing incidence of visual and systemic side effects.
关键词： nanofibers,electrospun,bacterial infection,single-dose,ocular,azithromycin
更新于2025-09-23 15:23:52
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Effect of nitrogen gas pressure during heat treatment on the morphology of silicon nitride fibers synthesized by carbothermal nitridation
摘要： The effects of N2 gas pressure on the diameter and morphology of Si3N4 fibers obtained via carbothermal nitridation were investigated. Sol–gel-derived precursors containing a silica and carbon mixture were placed in an Al2O3 crucible and heat-treated under various N2 pressures from 0.1 to 0.5 MPa at 1500oC. The heat-treated samples were characterized by X-ray diffraction (XRD), a scanning electron microscope (SEM) coupled with an energy dispersion X-ray (EDX) spectrometer, and transmission electron microscopy (TEM). Various nitride fibers with α- and β-phase Si3N4 were formed. The fiber diameter decreased with increases in N2 pressure, and nanometer-scale fibers of around 200 nm in diameter were obtained at a N2 pressure of 0.5 MPa. It was found that silicon oxynitride Si2N2O or its Al-doped form, O′-SiAlON, was produced due to high N2 pressure and doping with Al originating from the Al2O3 crucible. This oxynitride was considered to act as a template for Si3N4 fiber growth by the direct phase transformation mechanism. It was shown that the diameter of the Si3N4 fibers decreased for two reasons: decreased partial pressure of SiO gas due to high N2 pressure and increased formation of the silicon oxynitride templates.
关键词： carbothermal reduction,nanofibers,alumina,Silicon nitride
更新于2025-09-23 15:23:52