Nanomaterials
·
2018
·Vol. 8
·期 11
·918
·
IF 3.504
Dan Tian,Chun-Hui He,Ji-Huan He
Electrospinning is now commercially used for the fabrication of nano/micro fibers. Compared with spider dragline silk, artificial fibers have poor mechanical properties. Unlike natural silk, which has a hierarchical structure with an approximate 3-fold symmetry, the molecular structure of spun fiber has neither folding nor orientation. To date, it is almost impossible to control molecule orientation during the spinning process. Here, we show that macromolecule orientation can be easily controlled using the laminar flow of fluid mechanics. A lasting laminar flow in a long needle can order macromolecules. We find that the orientation of macromolecules can greatly affect the morphology and mechanical properties of fibers. We expect our technology to be helpful for more sophisticated fabrication of fibers with ordered macromolecules and DNA-like twists.Keywords:macromolecule;laminar flow;electrospinning;hierarchical structure
研究领域:
材料科学
·
生物物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymers
·
2023
·Vol. 15
·期 21
·4215
·
IF 5
Guixiang Chen,Zhenhang He,Zhen Liu,Xin Li,Zhengyin Yao,Peng Zhang
Paper-based thermoelectric (PTE) generators have recently emerged as a green technology that can help alleviate environment pollution and the energy crisis. In this work, a PTE generator was prepared by coating a post-treatment-free thermoelectric ink consisting of poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) doped with 1-ethyl-3-methylimidazolium:tricyanomethanide (EMIM:TCM) onto the card paper. By tuning the molar concentration of the EMIM:TCM to 0.17 M and with hot-pressing, the PTE generator showed a decent power factor (PF) value of 6.82 μW m−1K−2, which was higher than the values of PTE in the literature. This phenomenon could be attributed to the synergistic effect of high-performance thermoelectric ink (i.e., PF = 175 μW m−1K−2when deposited on glass slide) and the hot-pressing. The hot-pressing enhanced the packing density of cellulose fibers and the associated PEDOT:PSS hybrid, which enabled the formation of long-range conductive paths. In addition, the PTE had good mechanical stability, indicated by no significant change of the power factor values after cyclic folding 10,000 times. Moreover, the structure of as-prepared PTE could be easily tuned into different shapes that are promising for the preparation of flexible wearable thermoelectric generators.Keywords:paper-based thermoelectric;PEDOT:PSS;hierarchical structure;mechanical stability
研究领域:
材料科学
·
能源技术
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Jingtong Yu,De Sun,Dongmin Yue,Bingbing Li,Tie Zhu,Peixiang Liu
One of the most promising desalination techniques is photothermal membrane distillation (PhMD). The research focus of PhMD technology is material renewal and structural design. Herein, the CuMOF-PVDF photothermal membranes were designed for PhMD. Firstly, a combination of chemical plating and oxidation was used to generate Cu(OH) 2 nanowires (NWs) onto the PVDF membrane. Then, the ligands were chemically bonded with Cu(OH) 2 NWs to grow the photothermal layer formed by the CuMOF hierarchical structure (CMHS). Under sunlight irradiation, the light was trapped in the CMHS, amplifying absorption and conversion of light. The CuMOF-PVDF membrane with the match-like CMHS absorbed 88.6 % of the light, resulting in a surface temperature of 74.3 °C after 600s. Moreover, by reducing the evaporation enthalpy of water, the performance of the CuMOF photothermal layer was comprehensively improved, realizing a water evaporation rate of 1.55 kg‧m −2 ‧h −1 and a high photothermal conversion rate of 71.4 %. During the PVMD process, the feed solution in the CuMOF photothermal layer was fully heated and supplied to the vaporization area, weakening the temperature polarization. Consequently, the flux of the CuMOF-PVDF membrane was 3.07 kg‧m −2 ‧h −1 and a 99.9 % rejection rate, corresponding to an energy efficiency of 85.2 %. The CuMOF-PVDF membrane is an efficient tool for PhMD, helping to advance desalination technologies.
研究领域:
材料科学
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环境工程
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能源技术
✓ 已验证
产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Ding Wang,Kechuang Wan,Minglu Zhang,Huijun Li,Ping Wang,Xianying Wang,Junhe Yang
SnO 2 nanofiber/nanosheets with hierarchical nanostructures were successfully synthesized via a facile hydrothermal method by using hollow SnO 2 nanofibers as the backbone. The microstructure, morphology, chemical composition, oxidation states and surface areas of SnO 2 nanofibers, SnO 2 nanofiber/nanosheets and SnO 2 nanosheets were comparatively studied by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET). The characterization results indicated that the hierarchical SnO 2 nanofiber/nanosheets were constructed by nanosheets arrays uniform growth on the surface of nanofibers. Sensing performances of SnO 2 -based nanomaterials were investigated utilizing formaldehyde (HCHO) as a target gas. Compared to SnO 2 nanofibers, nanosheets and the physical mixture of nanofibers and nanosheets, the gas sensor based on SnO 2 nanofiber/nanosheets exhibited better response, more excellent selectivity, transient response and trace detection ability to HCHO gas. The response (R a /R g ) of the gas sensor is 57 toward 100 ppm HCHO at 120 °C, which is about 300% and 200% higher than that of pure SnO 2 nanofibers sensors and SnO 2 nanosheets sensors, respectively. Furthermore, the sensor has an excellent response/recovery performance with 4.7 s and 11.6 s for detecting 100 ppm HCHO. Both the growth process and the gas sensing mechanism of SnO 2 hierarchical nanostructures were discussed. Successful preparation of SnO 2 nanofiber/nanosheets is attributed to uniform decoration of seeds on the nanofibers and suitable growth conditions of nanosheets. Enhanced sensing performance mainly result from the synergistic effect of nanofibers and nanosheets, hierarchical structures and larger specific surface areas. The synthetic strategy can also be applied in preparing hierarchical materials of different constituent materials.
研究领域:
材料科学
·
传感器技术
·
环境监测
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Aihu Feng,Yang Yu,Le Mi,Yunzhen Cao,Yun Yu,Lixin Song
In this work, the hierarchical Y zeolites are firstly obtained by etching NaY zeolites with different NH 4 HF 2 solutions. The morphology and microstructure, toluene adsorption property of as-prepared hierarchical Y zeolites are characterized. The results demonstrate that the mesoporous number and size, the n(SiO 2 )/n(Al 2 O 3 ) value of hierarchical Y are increased with NH 4 HF 2 concentration. The 0.3M NH 4 HF 2 -etched NaY exhibits satisfactory crystallinity, suitable mesoporous content and better toluene adsorption performance. The NH 4 HF 2 -etched NaY is an excellent material for pressure swing adsorption. Furthermore, the synthesis mechanism of hierarchical Y has been elaborately demonstrated. The synergistic effect of H + and F − is beneficial to dealumination as well as the introduction of mesoporous. The NH 4 HF 2 ionizes into positive H + and negative F − at a very slow rate, which avoids the concentration of H + and F − going up suddenly. Under the circumstances, the dealumination reaction between NH 4 HF 2 and NaY zeolites is more sustained and mild, and the crystallinity of hierarchical Y zeolites is higher than that of the HCl/NH 4 F-etched or HF/NH 4 F-etched NaY. This work presents an effective method to synthesize the hierarchical Y zeolites.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Frontiers of Chemical Science and Engineering
·
2020
·Vol. 14
·期 5
·813-823
·
IF 3.552
Wang Mengyun,Zhang Shengbo,Li Mei,Han Aiguo,Zhu Xinli,Ge Qingfeng,Han Jinyu,Wang Hua
Novel, hierarchical, flower-like Ag/Cu 2 O and Au/Cu 2 O nanostructures were successfully fabricated and applied as efficient electrocatalysts for the electrochemical reduction of CO 2 . Cu 2 O nanospheres with a uniform size of ∼180 nm were initially synthesized. Thereafter, Cu 2 O was used as a sacrificial template to prepare a series of Ag/Cu2O composites through galvanic replacement. By varying the Ag/Cu atomic ratio, Ag 0.125 /Cu 2 O, having a hierarchical, flower-like nanostructure with intersecting Ag nanoflakes encompassing an inner Cu 2 O sphere, was prepared. The as-prepared Ag x /Cu 2 O samples presented higher Faradaic efficiencies (FE) for CO and relatively suppressed H 2 evolution than the parent Cu 2 O nanospheres due to the combination of Ag with Cu 2 O in the former. Notably, the highest CO evolution rate was achieved with Ag 0.125 /Cu 2 O due to the larger electroactive surface area furnished by the hierarchical structure. The same hierarchical flower-like structure was also obtained for the Au 0.6 /Cu 2 O composite, where the FE CO (10%) was even higher than that of Ag 0.125 /Cu 2 O. Importantly, the results reveal that Ag 0.125 /Cu 2 O and Au 0.6 /Cu 2 O both exhibit remarkably improved stability relative to Cu 2 O. This study presents a facile method of developing hierarchical metal-oxide composites as efficient and stable electrocatalysts for the electrochemical reduction of CO 2 .
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Advanced Ceramics
·
2021
·Vol. 10
·期 5
·1042-1051
·
IF 6.707
Du Heng,Zhang Qipeng,Zhao Biao,Marken Frank,Gao Qiancheng,Lu Hongxia,Guan Li,Wang Hailong,Shao Gang,Xu Hongliang,Zhang Rui,Fan Bingbing
In order to prevent the microwave leakage and mutual interference, more and more microwave absorbing devices are added into the design of electronic products to ensure its routine operation. In this work, we have successfully prepared MoS 2 /TiO 2 /Ti 3 C 2 T x hierarchical composites by one-pot hydrothermal method and focused on the relationship between structures and electromagnetic absorbing properties. Supported by comprehensive characterizations, MoS 2 nanosheets were proved to be anchored on the surface and interlayer of Ti 3 C 2 T x through a hydrothermal process. Additionally, TiO 2 nanoparticles were obtained in situ . Due to these hierarchical structures, the MoS 2 /TiO 2 /Ti 3 C 2 T x composites showed greatly enhanced microwave absorbing performance. The MoS 2 /TiO 2 /Ti 3 C 2 T x composites exhibit a maximum reflection loss value of −33.5 dB at 10.24 GHz and the effective absorption bandwidth covers 3.1 GHz (13.9–17 GHz) at the thickness of 1.0 mm, implying the features of wide frequency and light weight. This work in the hierarchical structure of MoS 2 /TiO 2 /Ti 3 C 2 T x composites opens a promising door to the exploration of constructing extraordinary electromagnetic wave absorbents.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2020
·
IF 6.215
Hanyong Wang,Lecai Wang,Jiao Lin,Jingbo Yang,Feng Wu,Li Li,Renjie Chen
The use of Li 4 Ti 5 O 12 , which is a zero-strain material, as an anode material for lithium-ion batteries is hampered by its low electronic conductivity and low lithium-ion diffusion coefficient . In this study, we design a hierarchically structured Li 4 Ti 5 O 12 material with a conductive carbon coating to improve the material's electrochemical properties. Hexadecyl trimethylammonium bromide is used as a structure-guiding agent and as a carbon source together with glucose. The discharge specific capacities of the obtained materials are 170.37, 167.34, 163.05, 158.03, and 151.49 mA h g −1 at rates of 0.5, 1, 2, 5, and 10 C, respectively. Even at a high rate, namely 25 C, for 500 cycles, a discharge specific capacity of 144.05 mA h g −1 with 96.3% capacity retention is achieved. We believe that hierarchical Li 4 Ti 5 O 12 materials with a carbon coating have potential applications as anode materials for the future development of lithium-ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Journal of the Mechanical Behavior of Biomedical Materials
·
2014
·
IF 3.048
Yi Chen,Jianming Wang,Jian Sun,Caiyun Mao,Wei Wang,Haihua Pan,Ruikang Tang,Xinhua Gu
It is widely accepted that the mechanical properties of dentin are significantly determined by its hierarchical structure. The current correlation between the mechanical properties and the hierarchical structure was mainly established by studying altered forms of dentin, which limits the potential outcome of the research. In this study, dentins with three different hierarchical structures were obtained via two different remineralization procedures and at different remineralization stages: (1) a dentin structure with amorphous minerals incorporated into the collagen fibrils, (2) a dentin with crystallized nanominerals incorporated into the collagen fibrils, and (3) a dentin with an out-of-order mineral layer filling the collagen fibrils matrix. Nanoindentation tests were performed to investigate the mechanical behavior of the remineralized dentin slides. The results showed that the incorporation of the crystallized nanominerals into the acid-etched demineralized organic fibrils resulted in a remarkable improvement of the mechanical properties of the dentin. In contrast, for the other two structures, i.e. the amorphous minerals inside the collagen fibrils and the out-of-order mineral layer within the collagen fibrils matrix, the excellent mechanical properties of dentin could not be restored.
研究领域:
牙科学
·
材料科学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 89
·73126-73132
·
IF 3.84
Liang Shi,Bohua Dong,Rongjie Gao,Ge Su,Wei Liu,Chenghui Xia,Fenghuan Zhao,Lixin Cao
Hierarchical flower-like Fe3O4@titanate microspheres with ultrathin nanosheets-assembled shell were fabricated via an effective step-by-step approach. Superparamagnetic Fe3O4 microspheres pre-formed were used as templates for perfect deposition of the following coatings. Silica middle layer was introduced by Stöber method in order to direct the formation of amorphous titania coverage via the hydrolysis of tetraisopropyl titanate. Under alkaline hydrothermal environment, titanate nanosheets crystallized and grew in situ attaching on the surface of Fe3O4 spheres, generating the flower-like microspheres which exhibit excellent adsorption properties. Meanwhile, the hierarchical structures can be tailored by varying the hydrothermal temperature and alkalinity, and the roles of sodium hydroxide and hydrogen peroxide were proposed.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2013
·
IF 3.172
Youcheng Zhao,Xinyu Song,Zhilei Yin,Qisheng Song
Controlled synthesis of CuO with various hierarchical structures consisting of self-organized nanoparticles is realized by using n-octylamine (OLA) as a structure inducing agent via a facile hydrothermal synthetic method. The growth and assemblage of CuO can be finely tuned by selecting the preparative parameters. In particular, it is found that the degree of the hierarchical organization can be modulated by simply changing the amount of the n-octylamine and CuO nanoparticles exhibit self-assembled two-dimensional (2D) sheet-like, three-dimensional (3D) disk-like and bowknot-like architectures, respectively. In the present case, OLA serves as a capping surfactant that can modulate growth of CuO nanocrystals via hydrophobic forces between the OLA molecules. CuO nanoparticles can be self-assembled into different complex architectures depending on the strength of hydrophobic forces. Hierarchical sphere-like CuO assembled from nanorods can also be easily fabricated by adjusting the starting NaOH to CuCl 2 volume ratio, in which OLA serves not only as the structure-directing agent, but also as a weak base agent to produce hydroxyl anions. The electrochemical performances of the as-synthesized different products for sensing nitrite oxidation are evaluated. The results reveal that the electrocatalytic activity is related to the secondary nanostructures. Compared to the others, the bowknot-shaped and sphere-shaped CuO products exhibit excellent electrocatalytic activity toward nitrite oxidation and fast current response in nitrite sensing because of their peculiar hierarchical structures with high BET surface areas and well-ordered pores.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2021
·
IF 3.927
Ping Ma,Xianliang Li,Yuchi Zhang,Le Han,Yan Xu
In this work, hierarchical spinel-type semiconductors MGa 2 O 4 (M = Ni, Co) were successfully synthesized via a facile hydrothermal method and a subsequent calcination strategy. The phase compositions, microstructures, as well as the gas sensing performances of these isostructural corn-like MGa 2 O 4 (M = Ni, Co) architectures were comparatively and systematically investigated. The experimental results showed that the hierarchical corn-like NiGa 2 O 4 spinel exhibited the optimum selective triethylamine (TEA) sensing performance with a gas response value (R g /R a ) of 7.60 at 270 °C, and excellent long-term stability for at least one month. The TEA gaseous sensing properties of these materials were significantly influenced by the transition metal M(II) ions dominated at the octahedral sites of spinel, and the sensing mechanism involving the surface redox reactions between the active oxygen species and TEA gases, as well as the charge carrier hopping process and changes of conductivity were discussed. This work not only demonstrated the facile preparation of hierarchical corn-like spinel-based gas sensors with rich active sites, we also discovered that the gas sensing performances of MGa 2 O 4 (M = Ni, Co) can be decisively modulated by the transition metal M(II)-ions.
研究领域:
材料科学
·
化学工程
·
传感器技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）