MATERIALS & DESIGN
·
2019
·
IF 5.77
Tingting Cheng,Siqi Li,Lan Xu,Adnan Ahmed
A modified electrospinning (MES), which consists of a copper mesh collector and an air pump placed behind it, was presented to fabricate nanofiber membranes (NFMs) with controllable large pore sizes by adjusting the MES parameters, such as copper mesh size, air velocity, applied voltage, flow rate and collecting distance. The controllable preparation mechanism of NFMs with large pore sizes was systematically investigated by experimental research and theoretical analysis. And the effects of the copper mesh grid dimensions, air velocity, applied voltage, flow rate and collecting distance on the pore sizes of NFMs were demonstrated. The results showed that NFMs with large pores produced successfully by the MES, and the pore sizes were all micrometer scale. And the optimal average pore size reached 14.45 μm 2 at the grid size of copper mesh of 4 mm×4 mm, the air velocity of 5 m/s, the applied voltage of 12 kV, the flow rate of 1.0 mL/h and the collecting distance of 18 cm.
研究领域:
材料科学
·
生物医学工程
·
纳米技术
·
组织工程
·
过滤材料
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2014
·Vol. 52
·期 17
·2442-2453
·
IF 3.245
Bingyan Jiang,Lei Zhang,Jie Yan,Qingquan Huang,Bing Liao,Hao Pang
A series of well-defined thermoresponsive graft polymers with different lengths and graft densities, poly(glycidyl methacrylate)- graft -poly( N -isopropylacrylate) (PGMA- g -PNIPAM), were successfully prepared by combination of controlled/living free radical polymerization and click chemistry. Effects of grafting length and density on the thermoresponsive behavior, aggregating mean diameter, and self-assembly morphology are systematically investigated. The thermosensitive characteristics of graft polymers in aqueous solution prove that the length and graft density had positive co-relationship with the lower critical solution temperature value and mean diameter of micelles as well as the size distribution, while the effect of graft length of polymers is more significant than that of density. Transmission electron microscopy analysis shows that the conformations of PGMA 45 - g -PNIPAM 20 and PGMA 45 - g -PNIPAM 46 with longer length and bigger grafting density in aqueous solutions are spherical nanoparticles with the increasing trend of the diameters, while that of PGMA 45 - g -PNIPAM (73, 50%) shows a spherical-like morphology, which indicates that the graft length and density have a significant effect on the mean diameter of micelle but not on the self-assembly morphology. These results reveal that to obtain desired thermoresponsive behavior and self-assembly morphology of functional polymers, it is essential to design and fabricate the structure of graft polymers with proper length and graft density. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52 , 2442–2453
研究领域:
高分子化学
·
材料科学
·
纳米医学
·
药物递送
·
生物材料
·
智能响应材料
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2023
·Vol. 11
·期 43
·23319-23329
·
IF 11.9
Bang-Zhou Tian,Yi-Yan Liao,Fang Xu,Xiao-Ling Qiu,Fu-Jie Zhang,Ran Ang
Interfacial modulation has been considered an effective strategy to enhance the thermoelectric (TE) performance by decoupling thermal and electrical parameters. However, inappropriate interfacial heterojunctions can significantly deteriorate electrical transport while enhancing phonon scattering, which causes no substantial improvement in TE performance. Herein, we introduce two-dimensional graphene or MXene into the Mg3.2Sb0.5Bi1.49Te0.01 matrix by ball mixing combined with rapid sintering to modify the composition and structure at the interface. The differences in morphology, size and distribution of interfacial graphene and MXene lead to distinct results which show that incorporated graphene flakes with larger size hinder the carrier transport, while the homogeneously dispersed tiny MXene provides improved carrier channels and boosts the mobility. On the other hand, such uniformly diffused heterogeneous MXene structures create stronger scattering on phonons compared to enriched graphene phases, resulting in a low lattice thermal conductivity of ∼0.66 W m−1 K−1 and enhanced zT of ∼1.0 at 513 K in Mg3.2Sb0.5Bi1.49Te0.01-0.6 wt% MXene with good component stability in air. This work highlights the importance of size, concentration, and distribution in the interfacial modulation strategy, demonstrating an effective method for developing high TE performance Mg3(Sb, Bi)2-based near-room-temperature materials.
研究领域:
材料科学
·
凝聚态物理
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纳米材料
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能源材料
·
固体化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2015
·Vol. 41
·期 3
·1550-1558
·
IF 3.313
Meilin Lv,Shuang Ni,Zhuo Wang,Tongcheng Cao,Xiaoxiang Xu
Doping has generally been served as one of the most efficient strategies for the improvement of wide band gap semiconductor photocatalysts . However, atomic arrangements of doped elements in the host crystal structure have often been overlooked, particularly during the investigation and evaluation of dopant functionality. It is known that electronic structures of a semiconductor are profoundly controlled by atomic occupancies in different crystallographic positions. Knowledge about dopant accommodations in the crystal structure and their influence towards photocatalytic performance is highly desired. Here, we investigated four compositional and structural relevant compounds CrNbO 4 , CrTaO 4 , Sr 2 CrNbO 6 and Sr 2 CrTaO 6 with the aim to study the effects of cation ordering/disordering upon their photocatalytic activity . Our results showed that ordered cations, namely Cr and Nb/Ta, are detrimental to the photocatalytic performance. Theoretical calculations indicate that cation ordering would enlarge the band gap and inhibit charge transfer between Cr and Nb/Ta. Our findings imply that ordered dopants in photocatalytic materials would severely offset the benefits of doping and might be a reason for the decreased activity at high doping levels often encountered.
研究领域:
材料科学
·
半导体物理
·
光催化
·
固体化学
·
能源材料
✓ 已验证
DOI
高影响因子
SCRIPTA MATERIALIA
·
2019
·
IF 4.539
Qingshuang Ma,Feng Lan,Xinhua Li,Zunfeng Du,Huijun Li,Zongqing Ma
In this work, the superconducting properties of FeSe 1−x S x with 0 ≤ x ≤ 0.5 were studied. With S doping, T c is enhanced and shows a dome shape in the studied composition range. XRD measurements demonstrate that S substituting Se sites introduces positive chemical pressure, which can suppress the orbital ordering, manifesting as the decrease of T s . Hall measurements demonstrate that S doping can effectively tune the charge carriers and make hole-type carriers predominant. However, no maxing T c is obtained as T s vanishes in FeSe 0.7 S 0.3 , indicating the nematic order has no universal influence on the superconductivity of FeSe system.
研究领域:
凝聚态物理
·
材料科学
·
低温物理学
·
强关联电子系统
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2016
·
IF 3.15
Lingwei Lu,Meilin Lv,Gang Liu,Xiaoxiang Xu
Constituting solid solutions has been an appealing means to gain control over various physicochemical properties. In this work, we synthesized a series of SrTiO 3 -BiFeO 3 solid solutions and systematically explored their structural, optical and photocatalytic properties. Our results show that all solid solutions crystallize in a primitive cubic structure and their band gap values can be easily tuned by adjusting molar ratios between SrTiO 3 and BiFeO 3 . Photocatalytic hydrogen production under both full range and visible light irradiation is greatly improved after forming solid solutions. The highest hydrogen production rate obtained is ∼180 μmol/h under full range irradiation (λ ≥ 250 nm) and ∼4.2 μmol/h under visible light irradiation (λ ≥ 400 nm), corresponding to apparent quantum efficiency ∼2.28% and ∼0.10%, respectively. The activity is found to be strongly influenced by surface area and light absorption. Theoretical calculation suggests that Fe contributes to the formation of spin-polarized bands in the middle of original band gap and is responsible for the band gap reduction and visible light photocatalytic activity .
研究领域:
材料化学
·
光催化
·
能源材料
·
无机固体化学
·
半导体物理
·
太阳能转化
·
表面科学
✓ 已验证
DOI
高影响因子
MACROMOLECULAR RAPID COMMUNICATIONS
·
2015
·Vol. 36
·期 15
·1437-1443
·
IF 4.941
Linge Wang,Paul D. Topham,Oleksandr O. Mykhaylyk,Hao Yu,Anthony J. Ryan,J. Patrick A. Fairclough,Wim Bras
Polymer beads have attracted considerable interest for use in catalysis, drug delivery, and photonics due to their particular shape and surface morphology. Electrospinning, typically used for producing nanofibers, can also be used to fabricate polymer beads if the solution has a sufficiently low concentration. In this work, a novel approach for producing more uniform, intact beads is presented by electrospinning self-assembled block copolymer (BCP) solutions. This approach allows a relatively high polymer concentration to be used, yet with a low degree of entanglement between polymer chains due to microphase separation of the BCP in a selective solvent system. Herein, to demonstrate the technology, a well-studied polystyrene-poly(ethylene butylene)–polystyrene triblock copolymer is dissolved in a co-solvent system. The effect of solvent composition on the characteristics of the fibers and beads is intensively studied, and the mechanism of this fiber-to-bead is found to be dependent on microphase separation of the BCP.
研究领域:
高分子科学
·
纳米材料
·
生物医学工程
·
药物递送
·
组织工程
✓ 已验证
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 112
·111052-111059
·
IF 3.289
Yuemei Li,Rui Wang,Yanling Xu,Jianjun Zhou,Zhihua Liu,Xiaojing Yan,Li Ma
ZnO:Yb3+,Tm3+,Ga3+ up-conversion nanoparticles (UCNPs) with sizes of between 20 and 65 nm are synthesized by the hydrothermal method. The size of the nanocrystals is affected by different Ga3+ concentrations. The variation in size has influence on the particles' visible blue and red up-conversion (UC) emission. In this paper, X-ray powder diffraction results show different amounts of gallium substituting for Zn in the ZnO lattice. When the concentration of Ga3+ is 3 mol%, the resulting UCNPs exhibit strong UC emission, longer fluorescence lifetime and narrower band gap. Due to their adjustable size and UC fluorescence properties, ZnO:Yb3+,Tm3+,Ga3+ nanocrystals have broad prospects for future applications in the biomedical field.
研究领域:
材料科学
·
纳米医学
·
生物光子学
·
无机功能材料
·
分子影像
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2017
·Vol. 33
·期 8
·850-855
·
IF 2.764
Nannan Bi,Lei Zhang,Qiang Zheng,Fei Zhuge,Jiupeng Li,Xuan P.A. Gao,Juan Du
A vapor deposition method was applied to synthesize zinc oxide (ZnO) nanowires and nanorods with diameter from 40 nm to 500 nm, length from 1 μm to 70 μm by adjusting the flow rate of argon, oxygen and the pressure during growth. Results of scanning electron microscopy (SEM) and high resolution transmission electron microscopy (TEM) proved the hexagonal wurtzite structure of the synthesized ZnO nanowires or nanorods , which grow along the <0001> direction. The results show that the growth conditions strongly impact the morphology, growth rate and optical properties of the ZnO nanostructures . The ZnO nanowires with small diameters tend to show stronger ultraviolet (UV) light emission from the electron-hole recombination near band edge in photoluminescence (PL), while those with larger diameters tend to exhibit PL spectra dominated by the broad green light emission due to the defects.
研究领域:
材料科学
·
纳米技术
·
半导体物理
·
光电子学
·
功能材料
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Yilin Huang,Wenjian Wang,Xingwang Hou,Ke Ran,Dongxu He,Shuai Wang,Yuan Fang,Rui Zhao,Weidong Xue
With the development of technology, microwave absorption technology shows its important position. In this work, A simple salt-template method was used to prepare copper phthalocyanine as N-doped graphene intercalated with CuO (CuO/NC). And a method to controllably regulate the dielectric constant by varying the ratio of salt templates and sintering temperature was proposed. When the treatment temperature is 900 °C and the ratio of salt template to raw material is 100:1, The minimum reflection loss (RL min ) of CuO/NC composite can reach −42.05 dB and the effective absorption bandwidth can reach 6.88 GHz with a thickness of 2.1 mm and a raw material filling of only 2 %, covering the entire Ku band. And the superior performance of the material was confirmed by simulation of the monostatic radar cross section. This research provides a new research direction for the synthesis of lightweight broadband microwave absorbing materials.
研究领域:
材料科学
·
纳米科技
·
电磁功能材料
·
复合材料
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2022
·
IF 4.598
Mingyuan Chen,Yaxin Lv,Peilin Wu,Liuyan Dong,Xingquan He,Lili Cui
To obtain highly active electrocatalyst for the whole electrochemical water splitting is of importance to generate hydrogen. Co(OH) 2 is used as electrocatalyst towards OER, however, the performance can be improved further. Usually, to construct the interface and adjust the electronic environment of electrocatalysts are regarded as powerful ways to improve the activity. Herein, CeO 2 -Co(OH) 2 sheets supported on copper foam (CF) are fabricated by electrodeposition method. The morphology and the electron structure of metals are adjusted by changing the molar ratio of Co to Ce, thus, resulting in different electrocatalytic activity. The optimal hybrids of CeO 2 -Co(OH) 2 exhibits lower overpotentials of 188, 269 mV to reach 10 mA cm −2 towards HER and OER, respectively, and good stability. Notably, it is found that the electroactivity is extremely superior to that of bare CF as well as the counterparts in the literature. Also, we try to employ M(OH) 2 (M = Fe, Ni) to substitute Co(OH) 2 to investigate the effect of species of hydroxides on the electron interaction between CeO 2 and hydroxides, the XPS results indicate that Ce and Co shows stronger electron interaction compared to other two control hydroxides. As electrocatalysts for alkaline full water splitting, CeO 2 -Co(OH) 2 requires a cell voltage of 1.62 V to drive 10 mA cm −2 . Experimental results prove the advantages of the electron engineering and morphology control.
研究领域:
材料科学
·
电化学
·
能源化学
·
纳米材料
·
催化化学
✓ 已验证
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2020
·
IF 4.244
Xiuyu Liu,Yan Jiang,Lijun Wang,Xueping Song,Chengrong Qin,Shuangfei Wang
This study explores the possibility of producing tunable cellulose nanofibers (CNFs) with a wide range of size and properties from sugarcane bagasse in an energy-efficient manner, which is very meaningful for specific application of CNFs. The bleached bagasse kraft pulp was subjected to endoglucanase pretreatment with a wide range of enzyme dosage followed by mechanical grinding to obtain size-tunable CNFs. The size distribution and structural characteristics of CNFs, energy consumed during the CNF production process, and properties of CNF films were systematically investigated as a function of the enzyme dosage applied in the pretreatment. The results showed that endoglucanase-assisted mechanical grinding was able to produce CNFs with controllable length (298–4500 nm) and diameter (9–26 nm), meanwhile improving CNF yield and energy-efficiency. The controllable range of CNF length was extremely wide based on our best knowledge. The optical performance and mechanical properties of the prepared CNF films could be effectively tuned by regulating the structural characteristics of the CNFs. Moreover, all the as-prepared CNFs retained high thermal stability. The tailor-made CNFs from sugarcane bagasse are expected to provide compatibility with various CNF-related applications.
研究领域:
材料科学
·
纳米技术
·
生物质转化
·
可再生资源
·
高分子材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）