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1
Sen, Dipanjan, e Markus J. Buehler. "Shock Loading of Bone-Inspired Metallic Nanocomposites". Solid State Phenomena 139 (aprile 2008): 11–22. http://dx.doi.org/10.4028/www.scientific.net/ssp.139.11.
Abstract (sommario):
Nanostructured composites inspired by structural biomaterials such as bone and nacre form intriguing design templates for biomimetic materials. Here we use large scale molecular dynamics to study the shock response of nanocomposites with similar nanoscopic structural features as bone, to determine whether bioinspired nanostructures provide an improved shock mitigating performance. The utilization of these nanostructures is motivated by the toughness of bone under tensile load, which is far greater than its constituent phases and greater than most synthetic materials. To facilitate the computational experiments, we develop a modified version of an Embedded Atom Method (EAM) alloy multi-body interatomic potential to model the mechanical and physical properties of dissimilar phases of the biomimetic bone nanostructure. We find that the geometric arrangement and the specific length scales of design elements at nanoscale does not have a significant effect on shock dissipation, in contrast to the case of tensile loading where the nanostructural length scales strongly influence the mechanical properties. We find that interfacial sliding between the composite’s constituents is a major source of plasticity under shock loading. Based on this finding, we conclude that controlling the interfacial strength can be used to design a material with larger shock absorption. These observations provide valuable insight towards improving the design of nanostructures in shock-absorbing applications, and suggest that by tuning the interfacial properties in the nanocomposite may provide a path to design materials with enhanced shock absorbing capability.
2
Seal, S., S. C. Kuiry, P. Georgieva e A. Agarwal. "Manufacturing Nanocomposite Parts: Present Status and Future Challenges". MRS Bulletin 29, n. 1 (gennaio 2004): 16–21. http://dx.doi.org/10.1557/mrs2004.11.
Abstract (sommario):
AbstractThe promises of nanotechnology are mostly based upon the ability to produce nanostructured materials with novel properties. Nanocomposites are defined here as a class of materials that contain at least one phase with constituents in the nanometer domain. This article describes the present state of knowledge of the fabrication of nanocomposite materials, with special emphasis on plasma forming of bulk parts. Future challenges facing the development of methods for consolidating nanocomposites with retained nanostructures are also highlighted.
3
Chang, Sujie, Xiaomin Wang, Qiaoling Hu, Xigui Sun, Aiguo Wang, Xiaojun Dong, Yu Zhang, Lei Shi e Qilei Sun. "Self-Assembled Nanocomposites and Nanostructures for Environmental and Energy Applications". Crystals 12, n. 2 (17 febbraio 2022): 274. http://dx.doi.org/10.3390/cryst12020274.
Abstract (sommario):
Self-assembled nanocomposites are attracting considerable attention owing to their controllable architectures and self-assembly processes, as well as the increase in worldwide environmental effects and energy needs. Further understanding of the self-assembly procedure for improving environmental and energy applications would advance the design and manufacture of nanomaterials for various applications. These materials can be grouped into major categories for various application fields, including powder photocatalysts, membrane photocatalysts, and thin-film thermoelectric nanomaterials. These self-assembled nanomaterials can be used for environmental and energy applications, such as wastewater purification, hydrogen production by water splitting, energy storage, and energy harvesting. In this review, a brief introduction to the definitions and classifications of self-assembled nanocomposites is provided. We aim to provide a summary of the recent research related to self-assembled nanocomposites and nanostructures used for environmental and energy applications. Moreover, typical examples and discussions are aimed at demonstrating the advantages of self-assembled nanostructures. At the end of each section, the structural properties and the application of the nanocomposite or nanostructure are summarized. Finally, we provide perspectives for future research on the design and fabrication of self-assembled nanocomposites and nanostructures.
4
Sharma, Deepali, B. S. Kaith e Jaspreet Rajput. "Single Step In Situ Synthesis and Optical Properties of Polyaniline/ZnO Nanocomposites". Scientific World Journal 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/904513.
Abstract (sommario):
Polyaniline/ZnO nanocomposites were prepared by in situ oxidative polymerization of aniline monomer in the presence of different weight percentages of ZnO nanostructures. The steric stabilizer added to prevent the agglomeration of nanostructures in the polymer matrix was found to affect the final properties of the nanocomposite. ZnO nanostructures of various morphologies and sizes were prepared in the absence and presence of sodium lauryl sulphate (SLS) surfactant under different reaction conditions like in the presence of microwave radiation (microwave oven), under pressure (autoclave), under vacuum (vacuum oven), and at room temperature (ambient condition). The conductivity of these synthesized nanocomposites was evaluated using two-probe method and the effect of concentration of ZnO nanostructures on conductivity was observed. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and UV-visible (UV-VIS) spectroscopy techniques were used to characterize nanocomposites. The optical energy band gap of the nanocomposites was calculated from absorption spectra and ranged between 1.5 and 3.21 eV. The reported values depicted the blue shift in nanocomposites as compared to the band gap energies of synthesized ZnO nanostructures. The present work focuses on the one-step synthesis and potential use of PANI/ZnO nanocomposite in molecular electronics as well as in optical devices.
5
Bang, Amruta, e Parag Adhyapak. "Synthesis of Au nanospheres, Au/PVDF nanocomposites and their breath sensing properties". Journal of ISAS 2, n. 2 (31 ottobre 2023): 51–62. http://dx.doi.org/10.59143/isas.jisas.2.2.qdai6853.
Abstract (sommario):
Herein, we report, a simple breath sensor based on Au/PVDF nanocomposites. Au nanostructures have been synthesized by using a simple seed mediated growth method. The synthesized Au nanostructures exhibited uniform spherical morphology with average diameter ~20 nm, confirmed by FESEM analysis. The synthesized nanostructures were further used to form nanocomposites with Polyvinylidene Fluoride (PVDF). The synthesized Au nanospheres as well as Au nanospheres/PVDF nanocomposites were tested for breath analysis. The nanocomposite materials were found to sense breath and uniform breathing patterns were generated. During breathing over sensor, voltage gets generated. The maximum voltage obtained was around 280 mV in breathing cycle.
6
Aït Hocine, Nourredine, Pascal Médéric e Hanaya Hassan. "Influence of mixing energy on the solid-state behavior and clay fraction threshold of PA12/C30B® nanocomposites". Journal of Polymer Engineering 39, n. 6 (26 luglio 2019): 565–72. http://dx.doi.org/10.1515/polyeng-2018-0307.
Abstract (sommario):
Abstract This study focuses on the influence of mixing energy on the solid-state behavior and clay fraction threshold of nanocomposites. Thus, three polyamide12/clay (PA12/C30B®) nanocomposites exhibiting different nanostructures were prepared from three sets of processing conditions. Then, thermal and dynamical viscoelastic properties of these nanocomposites were analyzed, in relationship with the material nanostructure and processing conditions. For the first time, the solid-state properties of the nanocomposites revealed the existence of a critical specific mixing mechanical energy. Below this critical value, an increase of mechanical energy refines the structure, improving some end-use properties of the nanocomposite. Above this value, a high mixing energy supply is necessary in order to significantly modify the structure. They also highlighted that the clay fraction threshold, which is commonly attributed to the formation of a three-dimensional percolated network, decreases with increasing specific mixing energy, less significantly when this energy is superior to its critical value.
7
Kikuchi, Masanori, e M. Tanaka. "Synthesis of Bone-Like Hydroxyapatite/Collagen Nano-Composites by Soft-Nanotechnology". Advances in Science and Technology 49 (ottobre 2006): 1–8. http://dx.doi.org/10.4028/www.scientific.net/ast.49.1.
Abstract (sommario):
Soft-nanotechnologies are based upon the synthesis technologies of nanomaterials and construction technologies of nanostructures by life forms. They are expected as new preparation methods for biomaterials that could be recognized as regular extracellular matrices (ECM) in our body by cells. We applied the soft-nanotechnology to synthesis of artificial bones made of HAp and collagen with bone-like nanostructure and examined their physical and biological properties. The nanocomposite obtained indicates bone-like nanostructure. Computer simulation and FT-IR suggested that the self-organization of HAp and collagen is based on chemical interaction between calcium ions on HAp surface and carboxy groups on collagen. After implantation in rats and dogs, the nanocomposites are resorbed by osteoclasts followed by osteogenesis; therefore, the nanocomposites are recognized as bone in the living body. Resorption rate can be controlled by crosslinkage. We also prepared sponge-like elastic porous body by gel-lyophilization technique using additional small amount of collagen solution. Bone tissue reactions of it are the same as the nanocomposites as prepared. The nanocomposites are now in clinical research in Japan to be commercialized in near future by Pentax Co.
8
Navyatha, Bankuru, e Seema Nara. "Gold nanotheranostics: future emblem of cancer nanomedicine". Nanobiomedicine 8 (gennaio 2021): 184954352110539. http://dx.doi.org/10.1177/18495435211053945.
Abstract (sommario):
Cancer nanotheranostics aims at providing alternative approaches to traditional cancer diagnostics and therapies. In this context, plasmonic nanostructures especially gold nanostructures are intensely explored due to their tunable shape, size and surface plasmon resonance (SPR), better photothermal therapy (PTT) and photodynamic therapy (PDT) ability, effective contrast enhancing ability in Magnetic Resonance imaging (MRI) and Computed Tomography (CT) scan. Despite rapid breakthroughs in gold nanostructures based theranostics of cancer, the translation of gold nanostructures from bench side to human applications is still questionable. The major obstacles that have been facing by nanotheranostics are specific targeting, poor resolution and photoinstability during PTT etc. In this regard, various encouraging studies have been carried out recently to overcome few of these obstacles. Use of gold nanocomposites also overcomes the limitations of gold nanostructure probes and emerged as good nanotheranostic probe. Hence, the present article discusses the advances in gold nanostructures based cancer theranostics and mainly emphasizes on the importance of gold nanocomposites which have been designed to decipher the past questions and limitations of in vivo gold nanotheranostics.
9
Marković, Darka, Andrea Zille, Ana Isabel Ribeiro, Daiva Mikučioniene, Barbara Simončič, Brigita Tomšič e Maja Radetić. "Antibacterial Bio-Nanocomposite Textile Material Produced from Natural Resources". Nanomaterials 12, n. 15 (24 luglio 2022): 2539. http://dx.doi.org/10.3390/nano12152539.
Abstract (sommario):
Growing demand for sustainable and green technologies has turned industries and research toward the more efficient utilization of natural and renewable resources. In an effort to tackle this issue, we developed an antibacterial textile nanocomposite material based on cotton and peat fibers with immobilized Cu-based nanostructures. In order to overcome poor wettability and affinity for Cu2+-ions, the substrate was activated by corona discharge and coated with the biopolymer chitosan before the in situ synthesis of nanostructures. Field emission scanning electron microscopy (FESEM) images show that the application of gallic or ascorbic acid as green reducing agents resulted in the formation of Cu-based nanosheets and mostly spherical nanoparticles, respectively. X-ray photoelectron spectroscopy (XPS) analysis revealed that the formed nanostructures consisted of Cu2O and CuO. A higher-concentration precursor solution led to higher copper content in the nanocomposites, independent of the reducing agent and chitosan deacetylation degree. Most of the synthesized nanocomposites provided maximum reduction of the bacteria Escherichia coli and Staphylococcus aureus. A combined modification using chitosan with a higher deacetylation degree, a 1 mM solution of CuSO4 solution, and gallic acid resulted in an optimal textile nanocomposite with strong antibacterial activity and moderate Cu2+-ion release in physiological solutions. Finally, the Cu-based nanostructures partially suppressed the biodegradation of the textile nanocomposite in soil.
10
Vysikaylo, P. I. "Quantum Size Effects Arising from Nanocomposites Physical Doping with Nanostructures Having High Electron Affinit". Herald of the Bauman Moscow State Technical University. Series Natural Sciences, n. 3 (96) (giugno 2021): 150–75. http://dx.doi.org/10.18698/1812-3368-2021-3-150-175.
Abstract (sommario):
This article considers main problems in application of nanostructured materials in high technologies. Theoretical development and experimental verification of methods for creating and studying the properties of physically doped materials with spatially inhomogeneous structure on micro and nanometer scale are proposed. Results of studying 11 quantum size effects exposed to nanocomposites physical doping with nanostructures with high electron affinity are presented. Theoretical and available experimental data were compared in regard to creation of nanostructured materials, including those with increased strength and wear resistance, inhomogeneous at the nanoscale and physically doped with nanostructures, i.e., quantum traps for free electrons. Solving these problems makes it possible to create new nanostructured materials, investigate their varying physical properties, design, manufacture and operate devices and instruments with new technical and functional capabilities, including those used in the nuclear industry. Nanocrystalline structures, as well as composite multiphase materials and coatings properties could be controlled by changing concentrations of the free carbon nanostructures there. It was found out that carbon nanostructures in the composite material significantly improve impact strength, microhardness, luminescence characteristics, temperature resistance and conductivity up to 10 orders of magnitude, and expand the range of such components’ possible applications in comparison with pure materials, for example, copper, aluminum, transition metal carbides, luminophores, semiconductors (thermoelectric) and silicone (siloxane, polysiloxane, organosilicon) compounds
11
Chen, Xin, Qiyan Zhang, Ziyu Liu, Yifei Sun e Q. M. Zhang. "High dielectric response in dilute nanocomposites via hierarchical tailored polymer nanostructures". Applied Physics Letters 120, n. 16 (18 aprile 2022): 162902. http://dx.doi.org/10.1063/5.0087495.
Abstract (sommario):
This paper presents a hierarchically designed polymer nanocomposite approach in which nanofillers at ultralow volume loading generate large dielectric enhancement in blends of high temperature dielectric polymers with tailored nanostructures. We blend poly(1,4-phenylenen ether sulfone) (PES) with polymers, such as polyetherimide (PEI), that possess more coiled chain conformations to tailor polymer nano-morphologies. Making use of such blends as the matrix, dilute nanocomposites with 0.65 vol. % loading of alumina nanoparticles (20 nm size) generate a marked enhancement in dielectric performance, i.e., raising the dielectric constant K from PES K = 3.9 (and PEI K = 3.2) to the dilute nanocomposites K = 7.6, a much higher enhancement compared with the dilute nanocomposites employing neat polymers as the matrix. The results show that polymer blends with tailored nano-morphologies as the matrix can lead to higher dielectric enhancement in dilute nanocomposites compared with neat polymers as the matrix.
12
Sarigamala, Karthik Kiran, Shobha Shukla, Alexander Struck e Sumit Saxena. "Graphene-Based Coronal Hybrids for Enhanced Energy Storage". Energy Material Advances 2021 (20 febbraio 2021): 1–15. http://dx.doi.org/10.34133/2021/7273851.
Abstract (sommario):
Functional materials with designer morphologies are anticipated to be the next generation materials for energy storage applications. In this manuscript, we have developed a holistic approach to enhance the surface area and hence the properties of nanostructures by synthesizing coronal nanohybrids of graphene. These nanohybrids provide distinctive advantages in terms of performance and stability over vertically stacked nanocomposites reported in literature. Various double hydroxide materials self-assembled as coronal lamellae on graphene shells have been synthesized and systematically studied. These coronal nanohybrids result in about a threefold increase in energy storage capacity as compared to their traditionally synthesized nanocomposite counterparts. The 3D graphene-based nanofibrils in the synthesized coronal nanohybrids provide mechanical support and connect the nodes of the double hydroxide lattices to inhibit restacking. Complex morphologies such as coronal nanostructures increase the interaction surface of the nanostructure significantly. Such an approach is also expected to bring a paradigm shift in development of functional materials for various applications such as sensors, energy storage, and catalysis.
13
Ivkov, Sergey A., Konstantin A. Barkov, Evelina P. Domashevskaya, Elena A. Ganshina, Dmitry L. Goloshchapov, Stanislav V. Ryabtsev, Alexander V. Sitnikov e Pavel V. Seredin. "Nonlinear Transport and Magnetic/Magneto-Optical Properties of Cox(MgF2)100-x Nanostructures". Applied Sciences 13, n. 5 (26 febbraio 2023): 2992. http://dx.doi.org/10.3390/app13052992.
Abstract (sommario):
The aim of this work was to comprehensively study the effect of the variable atomic composition and structural-phase state of Cox(MgF2)100-x nanocomposites on their nonlinear transport and magnetic/magneto-optical properties. Micrometer-thick nanocomposite layers on glass substrates were obtained by means of ion-beam sputtering of a composite target in the argon atmosphere in a wide range of compositions (x = 16–59 at.%). Using a low metal content in the nanocomposite, magnesium fluoride was kept in the nanocrystalline state. As the metal content increased, nanocrystalline cobalt was formed. The value of the resistive percolation threshold, xper = 37 at.%, determined from the concentration dependences of the electrical resistance of the nanocomposites coincided with the beginning of nucleation of the metallic nanocrystals in the MgF2 dielectric matrix. The absolute value of the maximum negative magnetoresistive effect in the nanocomposites was 5% in a magnetic field of 5.5 kG at a Co concentration of x = 27 at.%.
14
Habeeb, Majeed Ali, e Nawras Karim Al-Sharifi. "Improvement structural and dielectric properties of PS/SiC/Sb2O3 nanostructures for nanoelectronics devices". East European Journal of Physics, n. 2 (2 giugno 2023): 341–47. http://dx.doi.org/10.26565/2312-4334-2023-2-40.
Abstract (sommario):
In the current study, the PS/SiC/Sb2O3 nanocomposites have been prepared by using solution casting method with different concentrations of SiC/Sb2O3 nanoparticles (0,2,4,6,8) % wt. The structural and dielectric properties of (PS/SiC/Sb2O3) nanocomposites have been investigated. Full emission scanning electron microscope (FE-SEM) used to study the surface of nanocomposite. FE-SEM confirmed that good distribution of SiC and Sb2O3 NPs into the polymer matrix. Optical microscope (OM) was tested the morphological of nanocomposite that proven that the polystyrene is exceptionally miscible, as seen by its finer form and smooth, homogeneous surface, while the additive concentration SiC and Sb2O3 NPs are well distributed on the surface of the polymer nanocomposite films. Fourier transformation spectroscopy (FTIR) was examine the structural of nanocomposite and give the information of the vibration of molecules. From FTIR, the additive SiC and Sb2O3 NPs caused interaction with polymer matrix. FTIR proven that there is physical interactions between polystyrene and SiC and Sb2O3 NPs. According to AC electrical properties, dielectric constant and dielectric loss of the NCs reduce with increasing the frequency of the applied electric field and increased with increasing concentration of SiC/Sb2O3 nanoparticles, while AC electrical conductivity increased with increasing frequency and concentration of SiC/Sb2O3 NPs. The results of structural and electrical characteristics show that the PS/SiC/Sb2O3 nanocomposites may be used for various electronics devices.
15
Kononova, Irina, Vyacheslav Moshnikov e Pavel Kononov. "SnO2-Based Porous Nanomaterials: Sol-Gel Formation and Gas-Sensing Application". Gels 9, n. 4 (31 marzo 2023): 283. http://dx.doi.org/10.3390/gels9040283.
Abstract (sommario):
Porous nanocomposites using two (tin dioxide–silica dioxide) and three (tin dioxide–indium oxide-silica dioxide)-component systems for gas sensors were created with the sol–gel method. To understand some of the physical–chemical processes that occurred during the adsorption of gas molecules on the surface of the produced nanostructures, two models—the Langmuir model and the Brunauer–Emmett–Teller theory—were used to carry out calculations. The results of the phase analysis concerning the interaction between the components during the formation of the nanostructures were obtained through the use of X-ray diffraction, thermogravimetric analysis, the Brunauer–Emmett–Teller technique (to determine the surface areas), the method of partial pressure diagrams in a wide range of temperatures and pressures and the results of the measurement of the nanocomposites’ sensitivity. The analysis allowed us to find the optimal temperature for annealing nanocomposites. The introduction of a semiconductor additive into a two-component system based on tin and silica dioxides significantly increased the sensitivity of the nanostructured layers to reductional reagent gases.
16
Wang, Wenzhong, Xiao Yan, Bed Poudel, Yi Ma, Qing Hao, Jian Yang, Gang Chen e Zhifeng Ren. "Chemical Synthesis of Anisotropic Nanocrystalline Sb2Te3 and Low Thermal Conductivity of the Compacted Dense Bulk". Journal of Nanoscience and Nanotechnology 8, n. 1 (1 gennaio 2008): 452–56. http://dx.doi.org/10.1166/jnn.2008.062.
Abstract (sommario):
We describe a one-step, one-pot non-aqueous route for the synthesis of Sb2Te3 nanocrystals with hexagonal shape and highly anisotropic nanostructures. The as-prepared nanostructures were characterized by XRD, TEM and HRTEM. The effect of the stabilizers on the nanocrystal morphology has been discussed in detail. We have studied the thermal conductivity of the compacted bulk from the Sb2 Te3 nanostructures. The results indicated that a very low thermal conductivity of about 1 W/mK at 300 K, comparing to 4.7 W/mK of the polycrystalline bulk, was achieved. The results indicated that nanostructured Sb2 Te3 is potentially a good candidate for engineered nanocomposites that can lead to high thermoelectric figure-of-merit.
17
Padma, Tatiparti, Dheeraj Kumar Gara, Amara Nadha Reddy, Surya Veerendra Prabhakar Vattikuti e Christian M. Julien. "MoSe2-WS2 Nanostructure for an Efficient Hydrogen Generation under White Light LED Irradiation". Nanomaterials 12, n. 7 (31 marzo 2022): 1160. http://dx.doi.org/10.3390/nano12071160.
Abstract (sommario):
In this work, MoSe2-WS2 nanocomposites consisting of WS2 nanoparticles covered with few MoSe2 nanosheets were successfully developed via an easy hydrothermal synthesis method. Their nanostructure and photocatalytic hydrogen evolution (PHE) performance are investigated by a series of characterization techniques. The PHE rate of MoSe2-WS2 is evaluated under the white light LED irradiation. Under LED illumination, the highest PHE of MoSe2-WS2 nanocomposite is 1600.2 µmol g−1 h−1. When compared with pristine WS2, the MoSe2-WS2 nanostructures demonstrated improved PHE rate, which is 10-fold higher than that of the pristine one. This work suggests that MoSe2-WS2 could be a promising photocatalyst candidate and might stimulate the further studies of other layered materials for energy conversion and storage.
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Alguno, Arnold C., Katherine M. Emphasis, Melchor J. Potestas, Reynaldo M. Vequizo, Rey Y. Capangpangan, Bernabe L. Linog e Blessie A. Basilia. "Controlling the Growth of Zinc Oxide/ Polyaniline Nanocomposites on Platinum-Coated Substrate for Possible Solar Cell Applications". Solid State Phenomena 294 (luglio 2019): 30–35. http://dx.doi.org/10.4028/www.scientific.net/ssp.294.30.
Abstract (sommario):
We report on the growth of zinc oxide/polyaniline (ZnO/PANI) nanocomposites deposited on platinum (Pt)–coated glass substrate via chemical bath deposition and dip–casting technique is reported. Scanning electron micrographs of the nanocomposites revealed that etching of ZnO nanorods takes place during growth which turn into plate–like and distorted nanostructures. We found out that increasing the concentration of NH4OH triggered increase in nanostructure diameter. The surface morphology of nanocomposites significantly changed as the molar concentration of NH4OH precursor varies. Fast fourier transform infrared spectroscopy results showed the interaction of ZnO and PANI by observing the shift of peaks to the higher wavenumbers. The measured optical band gap of the nanocomposites are in good aggreement with the reported values. This result indicates that the grown ZnO/PANI nanocomposites is a good material for solar cell device.
19
Dai, Xiaobin, Cuiling Hou, Ziyang Xu, Ye Yang, Guolong Zhu, Pengyu Chen, Zihan Huang e Li-Tang Yan. "Entropic Effects in Polymer Nanocomposites". Entropy 21, n. 2 (15 febbraio 2019): 186. http://dx.doi.org/10.3390/e21020186.
Abstract (sommario):
Polymer nanocomposite materials, consisting of a polymer matrix embedded with nanoscale fillers or additives that reinforce the inherent properties of the matrix polymer, play a key role in many industrial applications. Understanding of the relation between thermodynamic interactions and macroscopic morphologies of the composites allow for the optimization of design and mechanical processing. This review article summarizes the recent advancement in various aspects of entropic effects in polymer nanocomposites, and highlights molecular methods used to perform numerical simulations, morphologies and phase behaviors of polymer matrices and fillers, and characteristic parameters that significantly correlate with entropic interactions in polymer nanocomposites. Experimental findings and insight obtained from theories and simulations are combined to understand how the entropic effects are turned into effective interparticle interactions that can be harnessed for tailoring nanostructures of polymer nanocomposites.
20
Kuriakose, Sini, D. K. Avasthi e Satyabrata Mohapatra. "Effects of swift heavy ion irradiation on structural, optical and photocatalytic properties of ZnO–CuO nanocomposites prepared by carbothermal evaporation method". Beilstein Journal of Nanotechnology 6 (10 aprile 2015): 928–37. http://dx.doi.org/10.3762/bjnano.6.96.
Abstract (sommario):
ZnO–CuO nanocomposite thin films were prepared by carbothermal evaporation of ZnO and Cu, combined with annealing. The effects of 90 MeV Ni7+ ion irradiation on the structural and optical properties of ZnO–CuO nanocomposites were studied by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV–visible absorption spectroscopy and Raman spectroscopy. XRD studies showed the presence of ZnO and CuO nanostructures in the nanocomposites. FESEM images revealed the presence of nanosheets and nanorods in the nanocomposites. The photocatalytic activity of ZnO–CuO nanocomposites was evaluated on the basis of degradation of methylene blue (MB) and methyl orange (MO) dyes under sun light irradiation and it was observed that swift heavy ion irradiation results in significant enhancement in the photocatalytic efficiency of ZnO–CuO nanocomposites towards degradation of MB and MO dyes. The possible mechanism for the enhanced photocatalytic activity of ZnO–CuO nanocomposites is proposed. We attribute the observed enhanced photocatalytic activity of ZnO–CuO nanocomposites to the combined effects of improved sun light utilization and suppression of the recombination of photogenerated charge carriers in ZnO–CuO nanocomposites.
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Ghelich, Raziyeh, Rouhollah Mehdinavaz Aghdam e Mohammad Reza Jahannama. "Elevated temperature resistance of SiC-carbon/phenolic nanocomposites reinforced with zirconium diboride nanofibers". Journal of Composite Materials 52, n. 9 (14 settembre 2017): 1239–51. http://dx.doi.org/10.1177/0021998317723447.
Abstract (sommario):
Carbon fiber-reinforced composites with matrices containing ultra-high temperature ceramics show excellent potential as high ablation-resistant materials. In this study, two non-oxide nanostructures, ZrB2 nanofibers and SiC nanoparticles, as reinforcement phases were utilized to develop the carbon/phenolic-ZrB2-SiC (C/Ph-ZS) nanocomposite for the first time. Thermogravimetry analysis illustrated that the residue yield of C/Ph composite at high temperatures was increased by the introduction of above-mentioned nanostructure ceramics. The addition of 7 wt% of ZrB2/SiC nanoadditives homogeneously in a C/Ph composite resulted in an enhancement of the room temperature thermal diffusivity, from 0.00622 to 0.00728 cm2/s. The incorporation of 4–7 wt% of ZrB2/SiC nanofillers in C/Ph composites leads to a reinforced material with about 73% increasing of Shore D hardness. The modified thermal behavior of prepared nanocomposites was examined using oxyacetylene torch at 2500℃ for 160 s. It suggested that the C/Ph-ZS7% nanocomposites with lower density may drastically contribute to meliorate the thermal insulation and ablative properties. The linear ablation rates of C/Ph composites were decreased after adding 7 wt% ZrB2/SiC nanofillers by 18%. The formation of a dense and uniform SiO2 and ZrO2 layer on the ablated surface of C/Ph-ZS nanocomposites could function as an effective oxygen barrier which greatly reduced the ablation rates of the nanocomposites because of the evaporation at elevated temperature, which absorbs heat from the flame and reduces the erosive attack to C/Ph. The ablated C/Ph-ZS nanocomposite with complicated cross-section structure displayed four dense oxidized, porous surface, transient and matrix regions.
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Saji, Viswanathan S. "Carbon nanostructure-based superhydrophobic surfaces and coatings". Nanotechnology Reviews 10, n. 1 (1 gennaio 2021): 518–71. http://dx.doi.org/10.1515/ntrev-2021-0039.
Abstract (sommario):
Abstract Research and development on superhydrophobic carbon nanostructures and their nanocomposites have high industrial significance. Here, a comprehensive review of the topic is provided. Reported works on superhydrophobic surfaces and coatings of carbon nanotubes, nanofibres, nanospheres/nanothorns/others, nanodiamond, fullerene and their various nanocomposites with metals, ceramics, and polymers are described. Superhydrophobic nanostructured carbon soot, graphitic carbon, and others are also presented. The section on superhydrophobic graphene is presented concisely at the end. Reports in different application areas, including anti-corrosion, anti-icing, oil separation, anti-biofouling, and sensors, are discussed separately. Superoleophobic and superamphiphobic surfaces are also discussed.
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Saheb, Hayat e Hassan. "Recent Advances and Future Prospects in Spark Plasma Sintered Alumina Hybrid Nanocomposites". Nanomaterials 9, n. 11 (12 novembre 2019): 1607. http://dx.doi.org/10.3390/nano9111607.
Abstract (sommario):
Although ceramics have many advantages when compared to metals in specific applications, they could be more widely applied if their low properties (fracture toughness, strength, and electrical and thermal conductivities) are improved. Reinforcing ceramics by two nano-phases that have different morphologies and/or properties, called the hybrid microstructure design, has been implemented to develop hybrid ceramic nanocomposites with tailored nanostructures, improved mechanical properties, and enhanced functionalities. The use of the novel spark plasma sintering (SPS) process allowed for the sintering of hybrid ceramic nanocomposite materials to maintain high relative density while also preserving the small grain size of the matrix. As a result, hybrid nanocomposite materials that have better mechanical and functional properties than those of either conventional composites or nanocomposites were produced. The development of hybrid ceramic nanocomposites is in its early stage and it is expected to continue attracting the interest of the scientific community. In the present paper, the progress made in the development of alumina hybrid nanocomposites, using spark plasma sintering, and their properties are reviewed. In addition, the current challenges and potential applications are highlighted. Finally, future prospects for developing alumina hybrid nanocomposites that have better performance are set.
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Sara, Djafar Vatan Khah Dowlat, Mojtaba Shamsipur e Ahmad Rouhollahi. "Ionic Liquid Aided Chemical Synthesis of Noble Metal Nanocomposites as Efficient Nanoelectrocatalysts". Advanced Materials Research 829 (novembre 2013): 589–93. http://dx.doi.org/10.4028/www.scientific.net/amr.829.589.
Abstract (sommario):
Platinum, Palladium and Gold nanocomposite using non-functionalized Multiwalled Carbon Nanotube (MWCNTs) has been prepared in the presence of phosphonium-based ionic liquid (Trihexyl Tetradecyl-phosphonium bis (trifluoromethylsulfonyl) amide) TTP(TFMS)2A. In this research, the presence of ascorbic acid (AA) in the quaternary phosphonium ionic liquid and MWCNTs without any modification, different noble metal nanocomposites of Pt, Pd and Au are formed. The mixture of MWCNT and IL has already been well-ultrasonicated until the best possible long-term stable dispersion to be formed. Under the similar time durations and similar concentrations of IL, the synthesis has been carefully performed. Working in these conditions leads to platinum-ionic liquid-MWNTs nanocomposite as black viscose powders. The nanostructures of the as-prepared nanopowders was checked with SEM. Using palladium nanocomposites as the modification agent on the glassy carbon electrode (GCE), the electrocatalytic effect of nanocomposites has been electrochemically investigated. Comparing three nanocomposites show that noble metal nanoparticles well supported on the bundles of MWCNTs but palladium NPs particle density is more than platinum NPs and PtNPs particle density is more than gold one. Anyway, the electrocatalytic activity of nanocomposites changes as PdNPs>PtNPs>AuNPs.
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Srinivasan, Sesha, Dervis Emre Demirocak, Ajeet Kaushik, Meenu Sharma, Ganga Ram Chaudhary, Nicoleta Hickman e Elias Stefanakos. "Reversible Hydrogen Storage Using Nanocomposites". Applied Sciences 10, n. 13 (3 luglio 2020): 4618. http://dx.doi.org/10.3390/app10134618.
Abstract (sommario):
In the field of energy storage, recently investigated nanocomposites show promise in terms of high hydrogen uptake and release with enhancement in the reaction kinetics. Among several, carbonaceous nanovariants like carbon nanotubes (CNTs), fullerenes, and graphitic nanofibers reveal reversible hydrogen sorption characteristics at 77 K, due to their van der Waals interaction. The spillover mechanism combining Pd nanoparticles on the host metal-organic framework (MOF) show room temperature uptake of hydrogen. Metal or complex hydrides either in the nanocomposite form and its subset, nanocatalyst dispersed alloy phases illustrate the concept of nanoengineering and nanoconfinement of particles with tailor-made properties for reversible hydrogen storage. Another class of materials comprising polymeric nanostructures such as conducting polyaniline and their functionalized nanocomposites are versatile hydrogen storage materials because of their unique size, high specific surface-area, pore-volume, and bulk properties. The salient features of nanocomposite materials for reversible hydrogen storage are reviewed and discussed.
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D. HUSSEIN, Amel. "FABRICATION SENSORS BASED ON NANOCOMPOSITES ZnO/PVDF". MINAR International Journal of Applied Sciences and Technology 04, n. 03 (1 settembre 2022): 123–28. http://dx.doi.org/10.47832/2717-8234.12.13.
Abstract (sommario):
This paper focused on generated output voltage by converting the mechanical energy to electrical response piezoelectric output voltage by tapping the finger of the hand on flexible nanogenerators fabrication of nanocomposites fibers (zinc oxide/polyvinylidene fluoride) ZnO/PVDF. Since, zinc oxide nanostructured materials have unique properties as their nanostructures, semiconducting, and piezoelectric which synthesize practically simply by a hydrothermal process at low temperatures. The structure and morphology of reactant materials, and, the fabricated nanofibers of the nanocomposites are characterized by XRD and SEM. The output is measured by an oscilloscope. The maximum output piezoelectric voltage for 18%ZnO–16%PVDF was 1.600 V. Therefore, the generators can be used as sensors in medical applications and other fields.
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Gwak, Gyeong-Hyeon, Min-Kyu Kim e Jae-Min Oh. "Nanocomposites of Magnetite and Layered Double Hydroxide for Recyclable Chromate Removal". Journal of Nanomaterials 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/8032615.
Abstract (sommario):
Nanocomposites containing magnetic iron oxide (magnetite) nanoparticles and layered double hydroxide (LDH) nanosheets were prepared by two different methods, exfoliation-reassembly and coprecipitation, for aqueous chromate adsorbent. According to X-ray diffraction, scanning electron microscopy, and atomic force microscopy, both nanocomposites were determined to develop different nanostructures; LDH nanosheets well covered magnetite nanoparticles with house-of-cards-like structure in exfoliation-reassembly method, while coprecipitation resulted in LDH particle formation along with magnetite nanoparticles. Zeta-potential measurement also revealed that the magnetite surface was effectively covered by LDH moiety in exfoliation-reassembly compared with coprecipitation. Time, pH, concentration dependent chromate adsorption tests, and magnetic separation experiments exhibited that both nanocomposites effectively adsorb and easily collect chromate. However, exfoliation-reassembly nanocomposite was determined to be slightly effective in chromate removal by ~10%. Chromate adsorbed nanocomposites could be regenerated by treating with bicarbonate and the regenerated nanocomposites preserved ~80% of chromate adsorption efficacy after three times of recycling.
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Navarro-Vega, Pedro, Arturo Zizumbo-López, Angel Licea-Claverie, Alejandro Vega-Rios e Francisco Paraguay-Delgado. "Equilibrium and Nonequilibrium Nanoscale Ordering of Polystyrene-b-poly(N,N′-diethylaminoethyl methacrylate), a Block Copolymer Carrying Tertiary Amine Functional Groups". Journal of Nanomaterials 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/725356.
Abstract (sommario):
Poly(styrene)-b-poly(N,N′-diethylaminoethyl methacrylate) (PS-b-PDEAEM) block copolymer was synthesized by RAFT free-radical polymerization using a trithiocarbonate type of chain transfer agent (CTA). Several block copolymer compositions were achieved maintaining low polydispersities by using PS as macro-CTA in the first step. Thin films of PS60%-b-PDEAEM40%were deposited over mica substrate, and its equilibrium and nonequilibrium nanostructures were studied. Lamellar (equilibrium), bicontinuous (nonequilibrium) and detached nanoflakes (nonequilibrium), were obtained by using different annealing methods. Mixing nanocomposites of gold nanoparticles/PDEAEM in the block copolymer resulted in the formation of toroidal nanostructures confining gold nanoparticles to the core of those nanostructures. The same toroidal nanostructure was achieved by different annealing methods, including irradiation with UV light for 15 min. Electron micrographs show clearly this different type of arrays.
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Shih, Yang Chia, Hui Hsuan Hsieh, Tzong Ming Wu e Chih Wei Chou. "The Characterization of Chitosan-Hyaluronan-Metal Nanocomposites". Advanced Materials Research 974 (giugno 2014): 97–101. http://dx.doi.org/10.4028/www.scientific.net/amr.974.97.
Abstract (sommario):
Chitosan and hyaluronan were used as biocompatible materials for biomedical application. In here, we prepared the Hyaluronan (HA) coated metal nanostructures. The chitosan (CS) films containing various concentrations of HA-coated Au or HA-coated Ag@Au nanostructures. We demonstrated that HA-coated spherical-like gold (HA-AuS), HA-coated wire-like gold (HA-AuW) or HA-coated Ag@Au could be dispersed in chitosan matrix by mixing and in aqueous solution casting. The introduction of HA-AuS, HA AuW and HA-Ag@Au nanostructures could not only improve the physical properties of CS, but also enhance the biocompatibility. The results revealed that the HA-AuS, HA AuW and HA-Ag@Au nanostructures enhanced the crystallinity of CS films. Besides, the hydrophilicity of CS films were improved by the HA-AuS, HA AuW and HA-Ag@Au nanostructures.
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Xing, Zhi-Cai, Seung-Jin Han, Yong-Suk Shin e Inn-Kyu Kang. "Fabrication of Biodegradable Polyester Nanocomposites by Electrospinning for Tissue Engineering". Journal of Nanomaterials 2011 (2011): 1–18. http://dx.doi.org/10.1155/2011/929378.
Abstract (sommario):
Recently, nanocomposites have emerged as an efficient strategy to upgrade the structural and functional properties of synthetic polymers. Polyesters have attracted wide attention because of their biodegradability and biocompatibility. A logic consequence has been the introduction of natural extracellular matrix (ECM) molecules, organic or inorganic nanostructures to biodegradable polymers to produce nanocomposites with enhanced properties. Consequently, the improvement of the interfacial adhesion between biodegradable polymers and natural ECM molecules or nanostructures has become the key technique in the fabrication of nanocomposites. Electrospinning has been employed extensively in the design and development of tissue engineering scaffolds to generate nanofibrous substrates of synthetic biodegradable polymers and to simulate the cellular microenvironment. In this paper, several types of biodegradable polyester nanocomposites were prepared by electrospinning, with the aim of being used as tissue engineering scaffolds. The combination of biodegradable nanofibrous polymers and natural ECM molecules or nanostructures opens new paradigms for tissue engineering applications.
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Chen, Xue-Gang, Ru-Chang Li, Ao-Bo Zhang, Shuang-Shuang Lyu, Shu-Ting Liu, Kang-Kang Yan, Wei Duan e Ying Ye. "Preparation of hollow iron/halloysite nanocomposites with enhanced electromagnetic performances". Royal Society Open Science 5, n. 1 (gennaio 2018): 171657. http://dx.doi.org/10.1098/rsos.171657.
Abstract (sommario):
Nanostructures loaded on halloysite nanotubes (HNTs) have attracted global interest, because the nanotubular HNTs could extend the range of their potential applications. In this study, we fabricated a novel nanocomposite with hollow iron nanoparticles loaded on the surface of HNTs. The structure of the iron nanoparticles can be adjusted by ageing time. Owing to the increased remnant magnetization and coercivity values, the nanocomposites loaded with hollow iron nanoparticles showed better electromagnetic performance than that with solid iron nanoparticles. This study opens a new pathway to fabricate halloysite nanotubular nanocomposites that may gain applications in the catalytic degradation of organic pollutants and electromagnetic wave absorption.
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Samantara, Aneeya K., Debasrita Dash, Dipti L. Bhuyan, Namita Dalai e Bijayalaxmi Jena. "Tuning the Photocatalytic Performance of Plasmonic Nanocomposites (ZnO/Aux) Driven in Visible Light". Current Catalysis 8, n. 1 (21 giugno 2019): 56–61. http://dx.doi.org/10.2174/2211544708666190124114519.
Abstract (sommario):
: In this article, we explored the possibility of controlling the reactivity of ZnO nanostructures by modifying its surface with gold nanoparticles (Au NPs). By varying the concentration of Au with different wt% (x = 0.01, 0.05, 0.08, 1 and 2), we have synthesized a series of (ZnO/Aux) nanocomposites (NCs). A thorough investigation of the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface has been carried out. It was observed that ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity among all concentrations of Au on the ZnO surface, which degrades the dye concentration within 2 minutes of visible light exposure. It was further revealed that with an increase in the size of plasmonic nanoparticles beyond 0.08%, the accessible surface area of the Au nanoparticle decreases. The photon absorption capacity of Au nanoparticle decreases beyond 0.08% resulting in a decrease in electron transfer rate from Au to ZnO and a decrease of photocatalytic activity. Background: Due to the industrialization process, most of the toxic materials go into the water bodies, affecting the water and our ecological system. The conventional techniques to remove dyes are expensive and inefficient. Recently, heterogeneous semiconductor materials like TiO2 and ZnO have been regarded as potential candidates for the removal of dye from the water system. Objective: To investigate the photocatalytic performance of different wt% of Au NPs on ZnO nanosurface and the effect of the size of Au NPs for photocatalytic performance in the degradation process. Methods: A facile microwave method has been adopted for the synthesis of ZnO nanostructure followed by a reduction of gold salt in the presence of ZnO nanostructure to form the composite. Results: ZnO/Au0.08 nanocomposite showed the highest photocatalytic activity which degrades the dye concentration within 2 minutes of visible light exposure. The schematic mechanism of electron transfer rate was discussed. Conclusion: Raspberry shaped ZnO nanoparticles modified with different percentages of Au NPs showed good photocatalytic behavior in the degradation of dye molecules. The synergetic effect of unique morphology of ZnO and well anchored Au nanostructures plays a crucial role.
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Gulab, Hussain, Nusrat Fatima, Nadia Shahzad, Muhammad Imran Shahzad, Mohsin Siddique, Muhammad Hussain e Muhammad Humayun. "Fabrication of Carbon/Zinc Oxide Nanocomposites as Highly Efficient Catalytic Materials for Application in Dye-Sensitized Solar Cells". Catalysts 12, n. 11 (3 novembre 2022): 1354. http://dx.doi.org/10.3390/catal12111354.
Abstract (sommario):
Different nanostructured semiconducting ZnO photoanodes were prepared by Hydrothermal (HT), Co-precipitation (CoP) and Chemical Bath Deposition (CBD) methods for their use in the Dye Sensitized Solar Cells (DSSCs) in the present study. Additionally, different ZnO nanocomposites were synthesized by mixing the Carbon Nanotubes (CNTs), Graphene Oxide (GO) and their combination with the ZnO nanostructures. Scanning electron microscopy (SEM) revealed various morphologies of ZnO nanostructures and nanocomposites such as nanoflowers, nanorods, rhombohedral, cubic, and cauliflower-like nanorods, and nanorods with hexagonal symmetry. Energy Dispersive X-ray (EDX) spectra confirmed the purity of the synthesized samples. X-ray Diffraction (XRD) demonstrated the hexagonal wurtzite phase of ZnO and a minor presence of CNTs and graphene. The UV-Visible, transmittance and diffuse reflectance spectra demonstrated that the ZnO synthesized through the CBD method exhibits the highest transmittance as 70–71% in the UV-Vis range and reduced % R. Optical band gaps of the samples were determined with the help of Tauc plots. Comparison of J-V characteristics showed that the ZnO synthesized via the HT method exhibits the highest conversion efficiency of 1.45%. Comparison among pristine ZnO synthesized via CBD and ZnO nanocomposites revealed that ZnO/CNTs possesses the highest energy conversion efficiency of 1.23% with enhanced JSC of 4.49 mA/cm2.
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Joshi, Hira, Siddharth Choudhary e S. Annapoorni. "Composite Nanostructures for Enhanced Plasmonics". Materials Science Forum 950 (aprile 2019): 165–69. http://dx.doi.org/10.4028/www.scientific.net/msf.950.165.
Abstract (sommario):
Enhancement in plasmonic response of metal nanoparticles in the form of metal/metal oxide nanocomposites is very interesting from both the theoretical understanding and application. Metal based oxide/Ag nanocomposites were synthesized by polyol process. Metal oxide nanoparticles present in nanocomposites as core and noble metal as a shell are of interest in investigation of plasmonic behavior of noble metals and sensing application. Cobalt ferrite (CoFe2O4) and ZnO were used as oxide core in the form of spherical and rod nanostructures respectively. Presence of Ag was confirmed by XRD and SEM analysis. In this paper we summarize the synthesis and characterization of plasmonic properties of composite nanostructures. Optical absorption studies performed on CoFe2O4@Ag and ZnO@Ag exhibit sharp plasmonic resonance but shifted towards lower wavelength (blue shift). An attempt has been made to explain this shift using the Mie scattering calculations based on size variation and change in the dielectric of the surrounding medium.
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Gautam, Krishna Prasad, Debendra Acharya, Indu Bhatta, Vivek Subedi, Maya Das, Shova Neupane, Jyotendra Kunwar, Kisan Chhetri e Amar Prasad Yadav. "Nickel Oxide-Incorporated Polyaniline Nanocomposites as an Efficient Electrode Material for Supercapacitor Application". Inorganics 10, n. 6 (19 giugno 2022): 86. http://dx.doi.org/10.3390/inorganics10060086.
Abstract (sommario):
This work reports the facile, controlled, and low-cost synthesis of a nickel oxide and polyaniline (PANI) nanocomposites-based electrode material for supercapacitor application. PANI-NiO nanocomposites with varying concentrations of NiO were synthesized via in-situ chemical oxidative polymerization of aniline. The XRD and FTIR support the interaction of PANI with NiO and the successful formation of the PANI-NiO-x nanocomposite. The SEM analysis showed that the NiO and PANI were mixed homogenously, in which the NiO nanomaterial was incorporated in porous PANI globular nanostructures. The multiple phases of the nanocomposite electrode material enhance the overall performance of the energy-storage behavior of the supercapacitor that was tested in 1 M H2SO4 using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). Among the different nanocomposites, PANI-NiO-3 exhibit the specific capacitance of a 623 F g−1 at 1 A g−1 current density. Furthermore, the PANI-NiO-3 electrode retained 89.4% of its initial capacitance after 5000 cycles of GCD at a 20 A g−1 current density, indicating its significant cyclic stability. Such results suggest that PANI-NiO nanocomposite could be proposed as an appropriate electrode material for supercapacitor applications.
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Potestas, Melchor Jocanain, Arnold C. Alguno, Reynaldo M. Vequizo, Bianca Rae B. Sambo e Majvell Kay G. Odarve. "Optical Property Enhancement of Silica-Modified Polyaniline Grown on Glass Substrate via Incorporation of Zinc Sulfide into the Polymer Matrix". Materials Science Forum 827 (agosto 2015): 192–99. http://dx.doi.org/10.4028/www.scientific.net/msf.827.192.
Abstract (sommario):
Growth of zinc sulfide (ZnS) nanostructures on silica modified-polyaniline (SM-PAni) with polymerization time-dependent was prepared using chemical bath deposition (CBD) technique. The grown samples were characterized by scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-Vis) spectroscopy. SEM images revealed some voids in the nanocomposites. The average diameter of the grown ZnS nanospheres did not significantly change by changing the growth time of the polyaniline. FTIR spectra and UV-Vis absorption spectra revealed the partial transformation of emeraldine salt polyaniline into emeraldine base PAni due to the deprotonation triggered during CBD for the synthesis of ZnS nanostructures. Furthermore, UV-Vis absorption spectra reveal synergistic effect of the absorption bands of both polyaniline and ZnS nanostructures. This synergistic effect results to the enhancement in the optical property of the fabricated nanocomposite which is an essential property in optoelectronics and solar cell application.
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Koleva, M. E., A. O. Dikovska, N. N. Nedyalkov e D. Karashanova. "Effect of laser annealing on the properties of Ag/ZnO nanostructures". Journal of Physics: Conference Series 2240, n. 1 (1 marzo 2022): 012008. http://dx.doi.org/10.1088/1742-6596/2240/1/012008.
Abstract (sommario):
Abstract Ag/ZnO nanostructures were synthesized using pulsed laser deposition (PLD) in open air (at atmospheric pressure). The deposition was carried out by a Nd:YAG laser, with the Ag layer composed of nanoparticles grown on SiO2 (001) substrates by the laser wavelength of 355 nm; this layer was covered by ZnO deposited by using the laser wavelength of 1064 nm. The samples were laser annealed, which led to a modification of the nanoparticles. The nanocomposites produced were characterized by TEM, UV-Vis and PL spectroscopy. The annealing procedures influence the optical properties of the Ag/ZnO nanocomposites. The laser annealing under certain parameters changes the emission behavior of the Ag/ZnO nanocomposite heterostructures. By employing localized surface plasmon resonance (LSPR), the near band edge (NBE) emission intensity of the ZnO films composed of nanoparticles was varied. An enhancement of the UV emission located at about 383 nm, commonly attributed to an excitonic transition, was registered after laser annealing with one pulse at the wavelength of 355 nm. The results obtained demonstrate that the annealing of Ag/ZnO composite nanostructures plays a key role in tuning the PL performance of a semiconductor material where an LSPR occurs.
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Doan, Mai Quan, Nguyen Ha Anh, Hoang Van Tuan, Nguyen Cong Tu, Nguyen Huu Lam, Nguyen Tien Khi, Vu Ngoc Phan, Pham Duc Thang e Anh-Tuan Le. "Improving SERS Sensing Efficiency and Catalytic Reduction Activity in Multifunctional Ternary Ag-TiO2-GO Nanostructures: Roles of Electron Transfer Process on Performance Enhancement". Adsorption Science & Technology 2021 (1 ottobre 2021): 1–13. http://dx.doi.org/10.1155/2021/1169599.
Abstract (sommario):
Multifunctional nanocomposites have received great attention for years; electron transfer (ET) is considered as an explanatory mechanism for enhancement of performance of these nanostructures. The existence of this ET process has been proved in many studies using either experimental or computational approaches. In this study, a ternary nanocomposite system of Ag/TiO2/GO was prepared to evaluate the performance enhancement in two experimental models: a physical model (i.e., surface-enhanced Raman scattering (SERS) sensor) and a chemical one (i.e., catalytic reduction reaction). The metal/semiconductor heterojunction between Ag and TiO2, as well as Ti-O-C bonds, has allowed plasmonic hot electrons to be transferred in the internal structure of the material. An investigation on the role of Ag content on the SERS sensing and catalytic reduction efficiency of Ag/TiO2/GO was performed in both models. Interestingly, they all resulted in the same optimal Ag content of 50 wt%. It was then further discussed to provide a convincing evidence for the plasmon-induced electron transfer phenomena in the Ag/TiO2/GO nanostructure. These findings also suggest a pathway to design and develop high-performance, cost-effective, facile-preparation, and eco-friendly multifunctional nanostructures for detecting and removing contaminants in environment.
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Kausar, Ayesha. "Shape memory polymer/graphene nanocomposites: State-of-the-art". e-Polymers 22, n. 1 (1 gennaio 2022): 165–81. http://dx.doi.org/10.1515/epoly-2022-0024.
Abstract (sommario):
Abstract Graphene is one of most exceptional type of nanocarbon. It is a two-dimensional, one atom thick, nanosheet of sp2 hybridized carbon atoms. Graphene has been employed as nanofiller for shape memory polymeric nanocomposites due to outstanding electrical conductivity, mechanical strength, flexibility, and thermal stability characteristics. Consequently, graphene nanostructures have been reinforced in the polymer matrices to attain superior structural, physical, and shape recovery properties. This review basically addresses the important class of shape memory polymer (SMP)/graphene nanocomposites. This assessment is revolutionary to portray the scientific development and advancement in the field of polymer and graphene-based shape memory nanocomposites. In SMP/graphene nanocomposites, polymer shape has been fixed at above transition temperature and then converted to memorized shape through desired external stimuli. Presence of graphene has caused fast switching of temporary shape to original shape in polymer/graphene nanocomposites. In this regard, better graphene dispersion, interactions between matrix-nanofiller, and well-matched interface formation leading to high performance stimuli-responsive graphene derived nanocomposites, have been described. Incidentally, the fabrication, properties, actuation ways, and relevance of the SMP/graphene nanocomposite have been discussed here. The potential applications of these materials have been perceived for the aerospace/automotive components, self-healing nanocomposites, textiles, civil engineering, and biomaterials.
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Kausar, Ayesha, Ishaq Ahmad, Malik Maaza e M. H. Eisa. "State-of-the-Art Nanoclay Reinforcement in Green Polymeric Nanocomposite: From Design to New Opportunities". Minerals 12, n. 12 (23 novembre 2022): 1495. http://dx.doi.org/10.3390/min12121495.
Abstract (sommario):
Nanoclays are layered aluminosilicate nanostructures. Depending upon the chemical composition and microscopic structure, various nanoclay types have been discovered such as montmorillonite, bentonite, kaolinite, halloysite nanoclay, etc. Nanoclays have been organically modified to develop compatibility with polymers. Polymer/nanoclay nanocomposites have prompted significant breakthroughs in the field of nanocomposite technology. Green nanocomposites form an important class of nanomaterials using naturally derived degradable materials as matrix/nanofiller. This review essentially deliberates the fundamentals and effect of nanoclay reinforcements in the green polymer matrices. Naturally derived polymers such as cellulose, starch, natural rubber, poly(lactic acid), etc. have been employed in these nanocomposites. Green polymer/nanoclay nanocomposites have been fabricated using various feasible fabrication approaches such as the solution route, melt processing, in situ polymerization, and others. The significance of the structure-property relationships in these nanomaterials, essential to attain the desired features, has been presented. Green polymer/nanoclay nanocomposites are light weight, inexpensiveness, ecofriendly, have a low cost, and enhanced indispensable physical properties. Consequently, the green polymer/nanoclay nanocomposites have found applications towards sustainability uses, packaging, membranes, and biomedical (tissue engineering, drug delivery, wound healing) sectors. However, thorough research efforts are desirable to extend the utility of the green polymer/nanoclay nanocomposites in future technological sectors.
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Chen, Xinrui, Wenbo Zhu, Jianwen Chen, Qing Cao, Yingxi Chen e Dengyan Hu. "TiO2 Nanoparticle/Polyimide Nanocomposite for Ultrahigh-Temperature Energy Storage". Nanomaterials 12, n. 24 (15 dicembre 2022): 4458. http://dx.doi.org/10.3390/nano12244458.
Abstract (sommario):
With the development of electronic technology, there is an increasing demand for high-temperature dielectric energy storage devices based on polyimides for a wide range of applications. However, the current nanofillers/PI nanocomposites are used for energy harvesting at no more than 200 °C, which does not satisfy the applications in the oil and gas, aerospace, and power transmission industries that require an operating temperature of 250–300 °C. Therefore, we introduced a nanocomposite based on nonsolid TiO2 nanoparticles and polyimide (PI) with high energy storage performance at an ultrahigh temperature of 300 °C. The synergy of excellent dielectric properties and a high breakdown strength endowed the nanocomposite with a low loading content of 1 wt% and a high energy storage density of 5.09 J cm−3. Furthermore, we found that the nanocomposite could stably operate at 300 °C with an outstanding energy storage capability (2.20 J cm−3). Additionally, finite element simulations demonstrated that the partially hollow nanostructures of the nanofillers avoided the evolution of breakdown paths, which optimized the breakdown strength and energy storage performance of the related nanocomposites. This paper provides an avenue to broaden the application areas of PI-based nanocomposites as ultrahigh-temperature energy-storage devices.
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Horbatenko, Yu V., V. V. Sagan, O. A. Korolyuk, O. O. Romantsova e A. I. Krivchikov. "Temperature dependences of thermal conductivity of solid heterogeneous crystalline and amorphous materials: An empirical approach to the description in the high-temperature region". Low Temperature Physics 50, n. 5 (1 maggio 2024): 379–88. http://dx.doi.org/10.1063/10.0025621.
Abstract (sommario):
This paper presents a detailed analysis of the thermal conductivity behaviors exhibited by a diverse array of nanostructured materials, ranging from multilayer graphene nanocomposites to semiconductor-based nanostructures such as Bi0.5Sb1.5Te3 and In0.53Ga0.47As composites. The investigation extends to superlattices, nanowires, and hybrid nanostructures, encompassing materials like hexagonal boron nitride flakes, iron oxide nanoporous films, and organic-inorganic hybrid materials. The thermal conductivity of these materials is characterized by distinct trends, with some showcasing crystal-like behavior and others demonstrating glass-like characteristics. The analysis employs empirical expressions to discern the contributions of phonons and diffusons in crystal-like materials and incorporates Peierls contributions and Arrhenius-type terms for glass-like behavior. Noteworthy observations include deviations in fitting certain materials at lower temperatures and the identification of negative diffuson contributions in specific cases. These findings contribute to a nuanced understanding of thermal transport in nanostructured materials and have implications for applications in advanced thermal management systems and thermoelectric devices. The extracted parameters provide valuable insights for researchers exploring the thermal conductivity of diverse nanostructured materials.
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Gurina, Galina, Kot Antonina, Kateryna Kaplina e Olexandra Vladyko. "OXIDE-REDUCED MECHANISM OF Fe(ІІІ) OXIDE REMOVAL FROM MONTMORILLONITE". Bulletin of the National Technical University "KhPI". Series: Innovation researches in students’ scientific work, n. 2 (22 dicembre 2023): 48–57. http://dx.doi.org/10.20998/2220-4784.2023.02.07.
Abstract (sommario):
The article proposes a redox mechanism for the bleaching of bentonite lump red clay and produces fillers for white paints and varnishes. Nanostructures of different types have been studied: intercalation compounds, delaminated nanocomposites, and mixed-type nanocomposites. Using the methods of IR spectroscopy, XRF analysis, laser diffraction, and DTA analysis, samples of synthesized organomodified bentonite were studied and the fact of intercalation of alkylbenzyldiethylamonium chloride molecules into the interlayer galleries of the crystalline inorganic matrix was established. A basic technological scheme for the production of bentonite fillers and organobentonite is presented. Nanocomposite hybrid paints and varnishes with the participation of new fillers and organobentonite have been obtained, and the physical and mechanical properties of new materials and coatings have been established.
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Wu, Di, Jun Guo, Zhen-Hua Ge e Jing Feng. "Facile Synthesis Bi2Te3 Based Nanocomposites: Strategies for Enhancing Charge Carrier Separation to Improve Photocatalytic Activity". Nanomaterials 11, n. 12 (14 dicembre 2021): 3390. http://dx.doi.org/10.3390/nano11123390.
Abstract (sommario):
Varying structure Bi2Te3-based nanocomposite powders including pure Bi2Te3, Bi2Te3/Bi core−shell, and Bi2Te3/AgBiTe2 heterostructure were synthesized by hydrothermal synthesis using Bi2S3 as the template and hydrazine as the reductant. Successful realization of Bi2Te3-based nanostructures were concluded from XRD, FESEM, and TEM. In this work, the improvement in the performance of the rhodamine B (RhB) decomposition efficiency under visible light was discussed. The Bi2Te3/AgBiTe2 heterostructures revealed propitious photocatalytic performance ca. 90% after 60 min. The performance was over Bi2Te3/Bi core-shell nanostructures (ca. 40%) and more, exceeding pure Bi2Te3 (ca. 5%). The reason could be scrutinized in terms of the heterojunction structure, improving the interfacial contact between Bi2Te3 and AgBiTe2 and enabling retardation in the recombination rate of the photogenerated charge carriers. A credible mechanism of the charge transfer process in the Bi2Te3/AgBiTe2 heterostructures for the decomposition of an aqueous solution of RhB was also explicated. In addition, this work also investigated the stability and recyclability of a Bi2Te3/AgBiTe2 heterojunction nanostructure photocatalyst. In addition, this paper anticipates that the results possess broad potential in the photocatalysis field for the design of a visible light functional and reusable heterojunction nanostructure photocatalyst.
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L, Girisha, Malteshkumar Deshpande, Gururaja Lakshman Naik e Mahanthesh M R. "Mechanical Characterization of Nanomaterial Reinforced Aluminum-based Hybrid Nanocomposites". Advanced Nano Research 2, n. 1 (25 maggio 2019): 32–41. http://dx.doi.org/10.21467/anr.2.1.32-41.
Abstract (sommario):
Nanostructures are viewed as definitive fiber materials as a reinforcement for matrices because of their impressive properties. Because of their phenomenal mechanical properties Carbon nanotubes (CNTs), graphene (GR), and nanodiamond (ND) have made an enormous proportion of intensity in research over the world. Multiwalled carbon nanotubes (MWCNTs), Graphene, and Nano Diamond were utilized as reinforcements for the current work. Nanostructures with their extraordinary strength, minute size, and high aspect ratio were used as reinforcements in commercial-purity Al matrix. These nanocomposites were manufactured by various different routes such as casting and powder metallurgy techniques. Both of these methods are helpful for the preparation of MWCNTs/Al nanocomposites. These nanocomposites were manufactured with various weight fractions of reinforcements and characterized for their mechanical properties and indicated improved properties in contrast with the base Al matrix. Al/MWCNT nanocomposites, Al/MWCNT/GR hybrid nanocomposites and Al/MWCNT/GR/ND hybrid nanocomposites samples were tested for their mechanical properties such as Young’s modulus, percentage elongation yield strength, and ultimate Strength. Mechanical characterization of these prepared composite samples demonstrated improved strength when compared with the casted samples.
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Kozlov, V. V., V. G. Kostishin, M. A. Sitnov e B. S. Godaev. "Study of the properties of nanocomposites based on thermally-treated-polyacrylonitrile (review)". Industrial laboratory. Diagnostics of materials 88, n. 8 (21 agosto 2022): 35–46. http://dx.doi.org/10.26896/1028-6861-2022-88-8-35-46.
Abstract (sommario):
Organic semiconductors and novel carbon forms (fullerene, carbon nanotubes, carbon foam, graphene) promote synthesis of carbon nanocomposites with modified properties based on thermally treated polyacrylonitrile (TPAN) that comprises curved (spherical, ring-like, and tube-like) carbon planes. Here we present a review of the studies regarding the properties of TPAN-based nanocomposites. The features of the IR irradiation procedure with a synergetic effect and the mechanism of polyacrylonitrile (PAN) transformation into carbon nanocrystalline material (CNM) have been analyzed. The developed method is promising for the synthesis of luminescent carbon nanostructures and biocompatible carbon nanostructures with high sensitivity to pH medium; metal-polymer nanocomposites (Ag/PAN, Cu/PAN, Fe3O4/TPAN), which can be used in electronics, catalysis, and in water purification from heavy metals, etc. The results obtained may be used to synthesize TPAN-based novel nanocomposites with modified properties.
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Balayeva, O. O. "SYNTHESIS OF DIFFERENT METAL DOPED ZnAl-LDH/PVA NANOCOMPOSITES FOR ADSORPTION AND PHOTOCATALYTIC APPLICATIONS". NNC RK Bulletin, n. 4 (31 dicembre 2022): 63–73. http://dx.doi.org/10.52676/1729-7885-2022-4-63-73.
Abstract (sommario):
Due to their high surface area, electronic properties, energy storage performance and catalytic activity, two-dimensional (2D) nanostructures have attracted significant interest and great attention in developing science. Layered double hydroxides (LDHs) belong to 2D nanostructures and have a high surface area, very important physicochemical properties, and biological activity. However, there has always been great interest in their doping to enhance and improve these unique properties, especially photocatalytic activity. In this work, ZnAl-based LDHs were synthesized and their doping with active- (Ca, Sr), transition- (Co, Cu, Cd, Ni, Pb, Fe), noble- (Ag) and rare earth- (La) metals were carried out by impregnation method. The removal of cationic and anionic dyes from aqueous solutions by adsorption and photodegradation on as-synthesized and doped ZnAl-LDH/PVA nanocomposite was also studied. The obtained results were correlated with the structure and physicochemical properties of the nanocomposites.
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Alshahrie, Ahmed, Ahmed A. Alghamdi, Prince M. Z. Hasan, Faheem Ahmed, Hanadi Mohammed Eid Albalawi, Ahmad Umar e Abdullah Alsulami. "Enhancement in the Performance of Dye Sensitized Solar Cells (DSSCs) by Incorporation of Reduced Graphene Oxide (RGO) and Carbon Nanotubes (CNTs) in ZnO Nanostructures". Inorganics 10, n. 11 (11 novembre 2022): 204. http://dx.doi.org/10.3390/inorganics10110204.
Abstract (sommario):
In this work, a fast, environment-friendly and economic route was used to prepare ZnO and their nanocomposites containing reduced graphene oxide (RGO) and carbon nanotubes (CNTs) for the fabrication of dye-sensitized solar cells (DSSCs). The prepared nanostructures were well-characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Raman measurements. The XRD, Raman and TEM results confirmed that the ZnO nanostructures were crystallized into the hexagonal phase, and the nanocomposites containing RGO and CNTs. Morphological studies performed by using FESEM and TEM images showed that the ZnO possessed tube-like morphology with length and diameter in the range of ~1 micron and 90–200 nm, respectively, which were uniform and densely covered on the surface of the carbon materials. The DSSCs were fabricated using prepared nanostructures as a working electrode and platinum as a counter electrode with ruthenium-based dyes and iodide electrolytes. To further improve the efficiency of fabricated solar cells, nanocomposites of prepared nanostructures of ZnO with RGO and CNTs were synthesized, and their results were compared with the pristine samples. The results showed that the ZnO/CNTs (0.5 wt%) nanocomposites electrode exhibited the highest power conversion efficiency (PCE) of DSSCs with a maximum value of 0.612% compared to 0.326% of DSSC with pure ZnO, and 0.574% of DSSC with ZnO/RGO. Significantly, this technique could be used for large-scale production using the existing economical and highly effective DSSC fabrication technique.
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Pawar, Shital Patangrao, Mounika Gandi, Chinmay Saraf e Suryasarathi Bose. "Exceptional microwave absorption in soft polymeric nanocomposites facilitated by engineered nanostructures". Journal of Materials Chemistry C 4, n. 22 (2016): 4954–66. http://dx.doi.org/10.1039/c6tc01062h.
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Vattikuti, S. V. Prabhakar, Jaesool Shim, Nam Nguyen Dang, P. Rosaiah, Mohammad Rezaul Karim, Ibrahim A. Alnaser e Baseem Khan. "Enhanced Photocatalytic and Electrochemical Performance of MOF-Derived NiO-ZnO Oxide Composites for Wastewater Treatment and Sustainable Energy Storage". International Journal of Energy Research 2024 (1 aprile 2024): 1–15. http://dx.doi.org/10.1155/2024/4589047.
Abstract (sommario):
Solar energy is a crucial and sustainable resource, necessitating material optimization for efficient use in solar-driven applications, particularly photocatalysis. Mixed-metallic nanocomposites, notably those derived from metal-organic frameworks (MOFs), have emerged as promising functional materials for environmental remediation and electrochemical energy storage. MOFs provide unique platforms for synthesizing diverse nanostructures, incorporating metals, oxides, sulfides, and nitrides within a porous carbon matrix. These resulting nanocomposites exhibit high crystallinity, retained morphologies, and tunable textural features. This study focuses on synthesizing a MOF-derived Ni/Zn nanocomposite (i.e., MD-Ni/Zn) from a bimetallic MOF to exploit its potential in photocatalytic pollutant degradation and electrochemical energy storage. Under UV irradiation, the MD-Ni/Zn nanocomposite efficiently degrades 98% of mixed (RhB+CV) dye within 60 minutes. This remarkable photocatalytic performance is attributed to the occurrence of mixed phases in the MD-Ni/Zn nanocomposite, minimizing the recombination efficiency of photoinduced e-/h+ through the p-n heterojunction mechanism. Electrochemical analysis reveals outstanding capacitance in the MD-Ni/Zn nanocomposite, reaching 1002 F/g at 5 A/g, emphasizing its suitability for enhanced electrochemical energy storage.