NANOTECHNOLOGY
·
2020
·Vol. 31
·期 19
·194001
·
IF 3.551
Bo Wang,Xin Huang,Xiao-Nan Zhou,Qiang Zhi,Liu-Cheng Hao,Zi-Xuan Li,Shan Zhao,Bao-Qiang Hou,Jian-Feng Yang,Kozo Ishizaki
One-dimensional Si3N4 nanostructures are desirable for constructing nanoscale electric and optoelectronic devices due to their peculiar morphologies. Herein, a facile and environmentally friendly catalyst-free method is proposed to synthesize ultra-long single crystal α-Si3N4 nanobelts via carbothermal nitridation of carbon nanotubes at 1750 °C. The obtained α-Si3N4 nanobelts with a flat surface (thickness of ∼150 nm, length of several millimeters) exhibited an extremely high aspect ratio, perfect crystal structure, and high specific surface area of 7.34–10.09 m2 g−1. In addition, the width was increased from approximately 80 nm to 8 μm by increasing the holding time from 1 to 3 h. The nanobelt formation was governed by the vapor–solid (VS) reaction between SiO vapor, N2 and carbon nanotubes, and the vapor–vapor reaction between SiO, CO and N2. The former was responsible for the initial nucleation and successive base-growth of α-Si3N4 nanotubes. The latter additionally contributed to the nanorod and subsequent proto-nanobelt formation and to the growth of the nanobelts. During high-temperature annealing at 1750 °C, the original Si3N4 nanotubes gradually transformed into nanorods, and, finally, nanobelts with stable shapes as a result of surface energy minimization.
研究领域:
材料科学
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纳米技术
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产品关联
DOI
PubMed
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2021
·
IF 2.495
Yuyue Guo,Yangfei Hu,Xiaojiong Luo,Shudong Lin,Jiwen Hu,Yuan Liu
The modified polyol method for the production of high aspect ratio silver nanowires (AgNWs) has received significant attention from many researchers due to its convenience and simplicity. Poly(vinylpyrrolidone) (PVP) is generally used as a template and capping agent in this method to stabilize the nanowires. However, the influence of different PVP molecules on the growth mechanism of AgNWs is not well understood. Given this, we designed a series of orthogonal experiments to obtain nanowires with an aspect ratio of 2500 and investigated the influence of PVP on the growing process leading to AgNWs. According to the results and previous studies, we proposed that relatively long PVP chains are apt to bond strongly with Ag atoms through their numerous carbonyl groups and thus promote the formation of long AgNWs. While promoting the growth in the AgNW's length, this mechanism of action restricts the growth of the diameter, thus leading to the formation of thin AgNWs with high aspect ratios as the final products.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2020
·Vol. 32
·期 10
·105710
·
IF 3.551
Lu Zhang,Fuliang Jiang,Bisheng Wu,Chencheng Lv,Minghua Wu
Silver nanowires (AgNWs), appear as an extremely promising candidate for the next generation of flexible transparent conductive electrodes (FTCEs). However, the performance of AgNWs-FTCEs was severely limited by the aspect ratio of AgNWs, while it was still a big challenge to fabricate AgNWs with high aspect ratio nowadays. To improve the aspect ratio of AgNWs, bromide ion (Br−), cupric ion (Cu2+) and polyvinylpyrrolidone (PVP, Mw ≈ 1300 000) which are beneficial for the synthesis of high aspect ratio AgNWs, were introduced in this article. The high quality and uniform AgNWs with the average diameter of 77.6 nm and the aspect ratio above 2000 were fabricated via a one-step solvothermal method. The effects of reaction time, molar ratio of AgNO3 to PVP and the concentration of CuBr2 on the aspect ratio of AgNWs were discussed. The mechanism of the synthesis of high aspect ratio AgNWs was explored. After that, the prepared AgNWs were spin-coated on the surface of PET film, the FTCEs based on the ultra-high aspect ratio AgNWs without any post-treatments exhibits relatively high transmittance, low haze and low sheet resistance, and the AgNWs have little effect on the optical performance of pristine PET film. The outstanding performance of the prepared FTCEs indicated that the ultra-high aspect ratio AgNWs are ideal materials in the application of FTCEs, and the method of fabricating AgNWs could provide a direction to the high aspect ratio AgNWs.
研究领域:
材料科学
·
纳米技术
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产品关联
DOI
PubMed
高影响因子
NANOTECHNOLOGY
·
2020
·Vol. 31
·期 14
·145601
·
IF 3.551
Rui Li,Xinyan Li,Ping-An Yang,Haibo Ruan
High-performance iron nanowires have attracted wide attention from researchers due to their 'controllable' arrangement distribution by magnetic fields. In this paper, a simple magnetic field assisted in situ reduction method was proposed to synthesize Fe NWs with high aspect ratio, small-diameter, and good dispersion. A detailed parametric study determining the relationship among the final morphologies of the products and magnetic field, injection sequence of sodium borohydride that was injected into ferrous sulfate heptahydrate, reactant concentration, and injection rate is presented. The as-synthesized Fe NWs were analyzed by scanning electron microscopy, transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy and vibrating sample magnetometry. A plausible mechanism for the formation of high-aspect-ratio Fe NWs is proposed. The SEM images showed the dependence of the NWs morphology and aspect ratio on synthesis parameters. Magnetic field and injection sequence showed considerable influences on the synthesis of high-aspect-ratio Fe NWs. In the absence of magnetic field or with the changes in injection sequence, only the Fe flakes were obtained. The NWs diameter decreased, and the aspect ratio increased with the increase in injection rate. The FeSO4·7H2O and NaBH4 concentration considerably influenced the aspect ratio of the product, which increased first, decreased, and then increased again with the increase in FeSO4·7H2O concentration. Meanwhile, the product aspect ratio increased and then became saturated with the increase in NaBH4 concentration Thus, an optimum synthesis process was obtained, with the average aspect ratio of 350, and the average diameter of 60 nm. The results reported in this paper provide a basis for optimizing the growth of Fe NWs by magnetic field-assisted method.
研究领域:
材料科学
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纳米技术
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产品关联
DOI
PubMed
高影响因子
CELLULOSE
·
2023
·Vol. 30
·期 9
·5607-5622
·
IF 5.7
Zhang Kecan,Li Jing,He Liang,Zhou Huajing,Guan Qingqing,Chen Keli,Shan Shaoyun,Hu Tianding
Cellulose nano/microfibres (CNFs/CMFs) with high aspect ratio were essential for mechanical strength and flexibility properties. In this study, the tobacco stem was employed as raw material for delignification with soda-oxygen (SO). By comparison with the caustic soda-anthraquinone (SAQ) treatment, based on process performance including pulp yield, residual lignin and fibre characteristics, the two-stage delignification process with total alkali 15% was selected for further preparing CNFs/CMFs with ultrasonication. Results showed that the aspect ratio of highly homogeneous CNFs/CMFs could achieve as ultra-high as 17,645. FTIR and XRD results showed that hemicellulose and lignin in CNFs/CMFs were widely removed, and the crystallinity was about 62%. TGA results exhibited that the degradation temperature was significantly enhanced to 330.2 °C. Finally, the CNF/CMF-based film was prepared and its folding endurance, tensile breaking strength, and burst strength could achieve 136, 61.28 N m/g, 278 kPa m 2 /g. The production of CNFs/CMFs from underutilized tobacco stems provided the potential to add value for industrial waste.
研究领域:
材料科学
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生物质利用
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2024
·
IF 7.1
Guangrui Ma,Wenqi Yin,Zhijun Shi,Yan Xu,Guang Yang
Carboxymethylation-modified cellulose nanofibrils (CMCNF) were prepared from bamboo fibers through a pretreatment process using a ternary deep eutectic solvent (DES) system consisting of chloroacetic acid, urea, and choline chloride. Grinding treatment was also employed. The properties of the resulting CMCNF were characterized using various analytical instruments including a fiber image analyzer, field-emission scanning electron microscope, X-ray diffractometer, and atomic force microscope. The results indicated that ternary DES pretreatment has the capability to carboxymethylate-modify the raw fiber material while maintaining the crystalline structure of cellulose. Additionally, it induced a wetting and swelling effect on the fibers, leading to the successful disruption of strong hydrogen bonds and the rapid production of cellulose nanofibrils during mechanical treatment. The carboxymethylation alteration enhanced the ability of the resultant CNF to disperse and increased the stability of the suspension. Furthermore, extending the duration of DES pretreatment enhances the process of fiber fibrillation and diminishes fiber polymerization. The CMCNF produced exhibited a high aspect ratio, with diameters ranging from 10 to 50 nm and lengths extending to a few micrometers. This study presents a novel approach and concept for producing carboxymethylated nanofibrillated cellulose. It also introduces a straightforward, environmentally friendly, and effective method for mass production of bamboo pulp nanofibrillated cellulose. This advancement is anticipated to enhance the processing and utilization of bamboo fiber resources, thereby contributing to an increased overall value.
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
GREEN CHEMISTRY
·
2023
·Vol. 26
·期 2
·879-894
·
IF 9.8
Yan Jiang,Xinyi Wang,Zhiqian Meng,Mengyang Zhang,Shuangfei Wang,Xiuyu Liu
It is of great technical interest but still challenging to develop a cost-effective and eco-friendly method to extract high-aspect-ratio elementary nanofibrils with native-state microstructure from recalcitrant lignocellulosic biomass because established chemical/biological/mechanical approaches inevitably give rise to the breakage of cellulose chains during the nanofibrillation of lignocellulose. Nature has designed hierarchical and heterogeneous lignocellulose structures, among which hemicellulose significantly affects interfibrillar interactions due to its unique molecular structure and micro-distribution pattern. Inspired by this fact, we amplify the hemicellulose stimulation effect on nanofibrillation using an on-demand regulated ionic liquid/water cosolvent and dissociate ultrahigh aspect ratio (2213) elementary fibrils (diameter = 4.7 nm) comprising approaching native-state structural carbohydrates from mildly delignified lignocellulose fibers (i.e. holocellulose) by a low-energy blender. We elucidated the mechanism for the exceptional disassembly behavior of holocellulose fibers: the high-level swelling of the amorphous and negatively charged hemicellulose phase weakens fibril–fibril interactions. The high-aspect-ratio morphology, well-preserved cellulose molecular structure, and hemicellulose-rich surface chemistry of the as-prepared nanofibrils significantly affect their self-assembly behavior and contribute to the extraordinary mechanical and optical performances of the corresponding nanopaper that conventional cellulose nano-papers/composites retain unsurpassed, e.g., overcome general conflicts between strength (310 MPa) and toughness (53 MJ m−3) and between transparency (86%) and haze (77%). This work provides a scale-up, ecologically and economically efficient lignocellulose nanostructure-engineered strategy for manufacturing high-performance structural nanomaterials towards a high-tech and carbon-neutral future.
研究领域:
材料科学
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生物质工程
✓ 已验证
DOI
高影响因子
ChemNanoMat
·
2024
·
IF 2.6
Xue Qi,Hao Lv,Yuxin Wang,Yang Ye,Peike Wang,Ao Yin,Jingjing Luo,Haipeng Liu,Zhongqi Ren,Jiang Liu,Suzhu Yu,Jun Wei
Flexible sensors, being a vital component of flexible devices, determine the functionalities and performance capabilities of the devices., especially, are widely used in flexible sensors in past research due to their great advantages in flexibility and sensitivity. In this work ， silver nanowires with aspect ratios of 600, 1000, and 1400 were synthesized by adjusting the synergy of Br– and Cl–, along with other process parameters, leading to an improved production efficiency of silver nanowires. The stability of the conductive network is enhanced when the aspect ratio of silver nanowires is 1000 and 1400.The sensor demonstrated high sensitivity at high strain, along with an extended strain range. Moreover, it was observed that increasing the aspect ratio of silver nanowires led to a more stable conductive network, thus enhancing the sensor's stability with over 10000 stretching cycles. under the appropriate deposition density, silver nanowires with aspect ratio of 600 have high sensitivity to low strain, and silver nanowires with aspect ratio of 1400 have high sensitivity to high strain, up to 247.3. Introducing microstructures on the surface of PDMS resulted in an increased maximum sensitivity of the sensor with decreasing microstructure size, reaching a maximum sensitivity of 322.2.
研究领域:
材料科学
·
传感器技术
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产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2020
·Vol. 31
·期 39
·395708
·
IF 3.551
Ping-an Yang,Haibo Ruan,Yang Sun,Rui Li,Yi Lu,Chenye Xiang
Reducing the filling content of high-density ferromagnetic particles is a key prerequisite for obtaining lightweight absorbers. To this end, large iron nanowires (Fe NWs) with high length-diameters, uniform length of approximately 21 μm and diameters of approximately 60 nm were synthesized through a facile magnetic field-induced in situ reduction method without templates and surfactants. The phase structures, and micromorphology of the high-aspect-ratio Fe NWs were analyzed, and the electromagnetic properties of Fe NWs-paraffin composites were measured with a vector network analyzer at 2–18 GHz. The Fe NWs-paraffin composite with a low filler loading also exhibited satisfactory microwave absorption performance, and the composites filled with 20 wt.% of as-prepared Fe NWs shows a minimum reflection loss (RLmin) of −44.67 dB at 2.72 GHz and effective absorption bandwidth (EAB) with reflection loss below −10 dB reached 8.56 GHz at a layer thickness of 1.42 mm. At a thickness of 3 mm, the RLmin value and EAB (RL ⩽ −10 dB) reached −29.74 dB and 3.28 GHz (3.84–7.12 GHz), respectively. This study suggests that Fe NWs with high-aspect-ratios have promising microwave absorbing applications, and provides a good reference for the preparation of ferromagnetic metal-based lightweight electromagnetic wave-absorbing materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Weilong Wu,Tianzhuo Zhan,Peng Wang,Zexia Li,Bo Li,Lu Meng,Zifeng Niu,Shijie Ma,Haoran Chen,Jun Zhang,Jahangeer Ahmed,Chengchun Tang,Yanming Xue
In the development of hexagonal boron nitride ( h -BN)/polymer composites, it is expected that efficient thermal transport networks constructed by the desired high-aspect-ratio (HAR) h -BN nanosheets (BNNSs) can be formed within them, thereby enhancing their heat dissipation capacity. In this work, a new and facile fusing-smashing method was developed to exfoliate h -BN. This method produces BNNSs with an outstanding aspect ratio of about 2200. Using these HAR-BNNSs as fillers, a series of BNNSs-based polymer composites were developed in the form of bulks, films, and adhesives with high thermal conductivity (TC) and mechanical performance. The maximum room temperature TC and compressive strength values of the formed 30BNNSs/rosin bulk composites are 3.13 ± 0.08 Wm -1 k −1 and 64 MPa, respectively. They show 62.6 times and 3.6 times the performance of the blank rosin. The in-plane TC and tensile strength of the 22BNNSs/Polyimide (PI) films are 14.4 ± 0.1 Wm -1 k −1 and 60 MPa, respectively, which are higher than those of the blank PI film (0.18 Wm -1 k −1 and 30 MPa). Noteworthy, compared to the blank adhesive of SMT (soyoil-malate-tannin), the TC of the prepared 2.5BNNSs/R/SMT composite adhesive is increased by 3.7 times, while its bonding strength also exhibits a 22 % enhancement, with only 2.5 wt% HAR-BNNSs filling fraction. In addition, all the HAR-BNNSs-filled composite materials manifest exceptional thermal diffusivity, indicating their potential for widespread application in thermal management for modern electronic devices.
研究领域:
材料科学
·
热管理技术
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产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2017
·Vol. 19
·期 24
·3263-3270
·
IF 3.474
He Ding,Xiuxiu Ni,Yixiao Zhang,Jingshuang Zhang,Zhouliangzi Zeng,Menglin Qi,Peng Bai,Xianghai Guo
High-aspect ratio b-oriented MFI nanosheets are synthesized by simply adding a suitable amount of graphene oxide (GO) nanosheets into a multilamellar MFI zeolite crystallization system. The GO nanosheets, serving as the building blocks for oriented attachment and in situ nucleation sites, positively induce the silicalite-1 nanosheet crystallization process and confine the over-growth of MFI crystals during the subsequent preparation. A two-dimensional (2D) induction mechanism of the GO nanosheets is discussed for the generation of the b-oriented MFI nanosheets. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), nitrogen adsorption, Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA).
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2018
·Vol. 5
·期 6
·066426
·
IF 1.151
Tianrui Chen,Haifeng Wang,Hui Yang,Shengchi Bai,Xingzhong Guo
Silver nanowires (AgNWs) with high aspect ratio were rapidly synthesized by a mixed polyols process by adding diethylene glycol, triethylene glycol and glycerol into the ethylene glycol to construct the mixed polyols respectively, and the effects of type and volume fraction of mixed polyols on the morphology and aspect ratio of AgNWs were investigated in detail, and the optoelectrical properties of the corresponding transparent conductive electrodes were briefly introduced. The presence of mixed polyols can increase the viscosity of the solution, reduce the migration rate of Ag+ and nuclear in the solution, decrease the diameter of silver nanowires and heighten the length and aspect ratio. Appropriate mixed polyols (triethylene glycol) with the volume fraction of 30% allows the rapid synthesis of AgNWs with the diameter of about 64.2 nm, the length of 66.0 μm and the aspect ratio as high as 1029. The as-prepared AgNWs films possess a transmittance of 89.8% and a sheet resistance of 4.56 Ω/sq. The resultant AgNWs with high aspect ratio can be applied to prepare transparent conductive films.
研究领域:
材料科学
·
纳米技术
·
化学工程
✓ 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）