MICROCHIMICA ACTA
·
2014
·Vol. 181
·期 9
·911-916
·
IF 3.719
Deng Hao-Hua,Li Guang-Wen,Liu Ai-Lin,Chen Wei,Lin Xin-Hua,Xia Xing-Hua
We demonstrate a sensitive and rapid colorimetric assay for selective detection of copper ions based on the strong coordination between Cu(II) ions and the tetrahydroxyaurate anions [Au(OH) 4 ] − on the surface of thermally treated bare gold nanoparticles (GNPs). The method for making the unmodified GNPs is simple and results in a nanomaterial with a highly specific response to Cu(II). The thermal treatment of the bare GNPs and the recognition of Cu(II) ions is accomplished in a single step within 5 min. The presence of Cu(II) causes the color to change from red to purple-blue. The limit of detection (LOD) is 0.04 μM of Cu(II) when using UV–vis spectrometry and ratioing the absorbances at 650 and 515 nm, respectively. The method also is amenable to bare eye (visual) inspection and in this case has an LOD of 2.0 μM of Cu(II).
Due to the strong coordination of Cu(II) ions with the tetrahydroxyaurate anions [Au(OH) 4 ] - on the thermally treated bare GNPs, Cu(II) can directly induce the aggregation of the GNPs, resulting in an obvious color change from wine-red to purple-blue.
研究领域:
分析化学
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纳米技术
·
环境科学
✓ 已验证
DOI
高影响因子
CELLULOSE
·
2021
·Vol. 28
·期 12
·7877-7891
·
IF 5.044
Ma Jianhua,Pu Haihong,He Pengxin,Zhao Qiangli,Pan Shaoxue,Wang Yaowu,Wang Chen
Multifunctional fibers have attracted widespread attention due to applications in flexible smart wearable devices. However, simultaneously obtaining a strong and functional woven fiber is still a great challenge owing to the conflict between the properties mentioned above. Herein, mechanically strong and highly conductive cellulose/carbon nanotube (CNT) composite fibers were spun using an aqueous alkaline/urea solution. The microstructure as well as physical properties of the resulting fibers were characterized via scanning electron microscopy, infrared spectroscopy, mechanical and electrical measurement. We demonstrated that carboxylic CNTs can be well dispersed in alkali/urea aqueous systems which also dissolved cellulose well. The subsequent wet spinning process aligned the CNTs and cellulose molecules inside the regenerated composite fiber well, enhancing the interaction between these two components and endowing the composite fiber having a 20% CNT loading with an excellent mechanical strength of 185 MPa. Benefiting from the formation of conductive paths, the composite fiber with the diameter of about 50 μm possessed an electrical conductivity value in the range of 64–1274 S/m for 5–20 wt% CNT loading. This excellent mechanical strength and high electrical conductivity enable the composite fiber to exhibit a great potential in joule heating; the heating temperature of cellulose/CNT-20 fiber reached more than 55 °C within 15 s at 9 V. In addition, the multifunctional filaments are further manufactured as a water sensor to measure humidity. This work provides a potential material that can be applied in the fields of wearable electronics and smart flexible fabrics. Graphic abstract
研究领域:
材料科学
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智能纺织品
·
柔性电子
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
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2021
·Vol. 39
·期 9
·1211-1216
·
IF 3.603
Xiang Ming-Yue,Lyu Dong,Liu Ling-Zhi,Men Yong-Feng
Crystallinity of bottlebrush polymers due to side chain crystallization has been considered to be related to the length of the side chains only under the assumption of complete participation of crystallization by all side chains. Recent experimental results revealed that in poly( n -alkyl methacrylate)s a fraction of side chains could not crystallize due to constraints imposed by the trapped main chain entanglements and required expansion of main chain-main chain distance. This result renders the original simplified consideration of the origin of crystallinity in bottlebrush polymers questionable. In this work, we introduce a new parameter f c , the fraction of crystallizable side chains, to better describe the crystallinity of bottlebrush polymers. A linear relationship between the melting enthalpy and the number of alkyl groups in side chains for bottlebrush polymers reported repeatedly indicates that f c remains essentially unchanged when bottlebrush polymers had the same main chain structure and grafting degree but different side chain lengths. The slope of the above-mentioned linear relationship is thus \(\Delta H_{\text{CH}_2}\times f_{c}\) , where \(\Delta H_{\text{CH}_2}\) stands for the melting enthalpy of one mole alkyl group packed into the crystal. With a known value of f c , it is possible to estimate the value of \(\Delta H_{\text{CH}_2}\) . In case of poly( n -alkyl methacrylate)s, we estimated \(\Delta H_{\text{CH}_2}\) of hexagonal crystal being at most 5.74 kJ/mol with the knowledge of possibly smallest f c of 0.67 obtained from small angle X-ray scattering data. Therefore, the crystallinity of bottlebrush polymer would be calculated based on the equation \(X_{\rm{c}}=f_{\rm{c}}\times\frac{N_{\rm{c}}}{N}\) with N and N c being the number of alkyl groups in a side chain and those packed in the crystalline structure, respectively. Both chemical structure and grafting degree of bottlebrush polymers affect f c .
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2014
·Vol. 32
·期 5
·531-539
·
IF 1.42
Xing Xin-ming,Liu Guang-ming,Ding Yan-wei,Zhang Guang-zhao
The lower critical solution temperature (LCST) behavior of poly(acrylamide- co -diacetone acrylamide) (poly(AM- co -DAM)) copolymer in aqueous solutions was studied. The results demonstrate the LCST linearly decreases as the molar fraction of DAM ( f
DAM ) increases. In the range of f
DAM < 0.36, the transmittance increases as f
DAM decreases because the more hydrophilic copolymer chains can form looser aggregates with a lower refractive index. The transmittance exhibits a minimum when f
DAM is less than 0.28 as the chains form micelle-like structure with a size smaller than the wavelength. The LCST decreases with the initial polymer concentration, but it levels off when the polymer concentration is high enough. Moreover, no hysteresis can be observed in the change of transmittance during the heating-cooling process because no additional hydrogen bonds are formed in the collapsed state due to the steric hindrance of the large side groups in DAM units.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-12
·
IF 14.7
Cui Zhuangzhuang,Jia Zhuangzhuang,Ruan Digen,Nian Qingshun,Fan Jiajia,Chen Shunqiang,He Zixu,Wang Dazhuang,Jiang Jinyu,Ma Jun,Ou Xing,Jiao Shuhong,Wang Qingsong,Ren Xiaodi
Constraining the electrochemical reactivity of free solvent molecules is pivotal for developing high-voltage lithium metal batteries, especially for ether solvents with high Li metal compatibility but low oxidation stability ( <4.0 V vs Li + /Li). The typical high concentration electrolyte approach relies on nearly saturated Li + coordination to ether molecules, which is confronted with severe side reactions under high voltages ( >4.4 V) and extensive exothermic reactions between Li metal and reactive anions. Herein, we propose a molecular anchoring approach to restrict the interfacial reactivity of free ether solvents in diluted electrolytes. The hydrogen-bonding interactions from the anchoring solvent effectively suppress excessive ether side reactions and enhances the stability of nickel rich cathodes at 4.7 V, despite the extremely low Li + /ether molar ratio (1:9) and the absence of typical anion-derived interphase. Furthermore, the exothermic processes under thermal abuse conditions are mitigated due to the reduced reactivity of anions, which effectively postpones the battery thermal runaway.
研究领域:
电化学
·
材料科学
·
电池技术
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2014
·Vol. 21
·期 6
·1-8
·
IF 1.897
Yue Zhouying,Cai Yang-Ben,Xu Shiai
A new symmetrical diamine that contains benzimidazole ring, 6,6’-bis[2-(4-aminophenyl)benzimidazole], was synthesised directly from p -aminobenzoic acid and 3,3’-diaminobenzidine via benzimidazolisation condensation. The diamine monomer was polymerised with various commercial dianhydrides by a conventional two-step polymerisation reaction to obtain the corresponding polyimides. The obtained polyimides were amorphous and could be used to produce flexible, yet tough, transparent films exhibiting excellent thermal stability with glass transition temperatures of 334 °C to 412 °C and 5 % weight loss temperatures above 540 °C in nitrogen. These polymers also demonstrated outstanding mechanical properties with a tensile strength of 177 MPa to 224 MPa and a tensile modulus of 3.5 GPa to 5.7 GPa. The excellent thermal and mechanical properties of these polyimides are most likely attributable to the rigid-rod structure and the presence of hydrogen bond between the macromolecular chains.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
OPTICAL AND QUANTUM ELECTRONICS
·
2021
·Vol. 53
·期 10
·1-8
·
IF 2.084
Li Chunfang,Zhang Hongyan,Xue Qihao,Li Dongxiang
Azobenzene compounds have been widely used in many fields and through their response to light they can be used to regulate the properties of ordered structures. In this paper, sub-micrometer colloidal SiO 2 spheres were prepared and azobenzene groups were grafted on the surface of SiO 2 microspheres. The SiO 2 microspheres grafted with azobenzene groups could self-assemble to form photosensitive photonic crystals, whose photonic bandgaps red-shifted as irradiated by UV light due to the structure change of the azobenzene groups.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
CELLULOSE
·
2018
·Vol. 25
·期 2
·1499-1511
·
IF 3.809
Chen Yong,Zhang Qiang,Ma Yijia,Han Qiuxia
Most research efforts focus on synthesis of new biocides. This study shows that orientating biocidal groups on top surface with the help of a low-surface-tension constituent also imparts enhanced antibacterial ability. A CO 2 -philic biocidal silicone with pyridinium pendants was synthesized by hydrosilylation reaction of (45% methylhydrosiloxane)–dimethylsiloxane random copolymer (P(MHS–DMS)) and 4-vinylpyridine and subsequent quaternization of pyridine groups with 6-perfluorooctyl-1-bromohexane. The fluorinated pyridinium silicone was impregnated into cotton yarns in supercritical CO 2 to form a 50 nm thickness biocidal layer at 24 MPa and 50 °C. Pyridinium groups preferentially segregated to the top surface with the aid of low-surface-tension perfluorooctyl segments and provided higher biocidal efficacy against Staphylococcus aureus and Escherichia coli compared to their counterparts that were quaternized with 1-bromohexane at similar total pyridinium content of about 4.65 × 10 16 /cm 2 . The synthesis and coating results were characterized by FTIR, SEM, and XPS. The stabilities of fluorinated pyridinium silicone layer toward washing cycles, UV irradiation, and storage were good. The presented strategy uses environmentally benign CO 2 as solvent and affords a general method to functionalize polymers for improved biocidal capability due to the surface orientation of pyridinium groups.
研究领域:
材料科学
·
生物学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS RESEARCH
·
2021
·Vol. 36
·期 9
·1835-1845
·
IF 3.089
Chen Changsong,Wu Yihua,Zhu Zhi-Gang,Shih Wan Y.,Shih Wei-Heng
Abstract All-inorganic perovskite materials have many advantages such as adjustable emission range, narrow emission peaks, and good crystallinity, which have attracted widespread interest. They can be used as solar cells, LEDs, photodetectors, displays, and other optoelectronic devices. However, poor environmental stability is the major factor limiting its applications. We introduced a Poly(styrene-ethylene-butylene-styrene) SEBS polymer to create perovskite/SEBS composite films which have excellent stability even in the water environment. Besides, due to the elastic nature of SEBS, the composite films exhibited good mechanical deformability and could maintain most of its fluorescence intensity after being stretched hundreds of times. A WLED device was constructed by stacking CsPbBr 3 /SEBS films and CsPbI 3 /SEBS films over a blue LED. The WLED performed well with color rendering index of 82.6 with chromaticity coordination (0.35, 0.36) and color temperature 4784 K. Graphic Abstract
In order to create a stable and flexible photoluminescent material, we combined a
poly(styrene-ethylene-butylene-styrene) (SEBS) polymer and cesium lead-halide
nanocrystals forming a flexible photoluminescent composite. The composite films
show both good environment stability and excellent flexibility.
研究领域:
材料科学
·
光电技术
·
纳米技术
·
光子学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2015
·Vol. 26
·期 11
·8413-8420
·
IF 1.569
Tian Jiao,Ma Qianli,Dong Xiangting,Yang Ming,Yang Ying,Wang Jinxian,Yu Wensheng,Liu Guixia
The flexible color-tunable [Eu(BA) 3 phen + Tb(BA) 3 phen]/PMMA composite nanobelts have been fabricated by single axial electrospinning. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and fluorescence spectroscopy were used to characterize the final products. As-prepared nanobelts are almost uniform and the thickness and width of them are respectively ca. 890 nm and 16.6 ± 0.09 μm. The fluorescence intensity of Eu 3+ is increased with adding more Eu(BA) 3 phen into the composite nanobelts, and the fluorescence intensity of Tb 3+ is found to increase monotonically with introducing more Tb(BA) 3 phen into the composite nanobelts. By adjusting the ratio of Eu(BA) 3 phen to Tb(BA) 3 phen complexes, the fluorescence color of composite nanobelts can be tuned from red to yellow, yellow green, and green under the excitation of 290-nm single-wavelength ultraviolet light. Besides, the emission color could also be tuned easily from red to yellow, yellow to green via variation of excitation wavelengths. The novel color-tunable composite nanobelts have potential applications in the fields of color displays and sensor systems.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
·
2019
·Vol. 50
·期 10
·4827-4838
·
IF 1.985
Liu Jun-Kai,Zhang Guo-Hua,Sun Guo-Dong
We propose a process to produce ultrafine W-10 wt pct Cu composite powders by reducing the mixtures of copper tungstate (CuWO 4 ) and tungsten trioxide (WO 3 ) (from the calcination of a mixture of ammonium paratungstate and copper nitrate trihydrate) with carbon black and hydrogen. First, ultrafine pre-reduced tungsten-copper (W-Cu) powders containing a small amount of WO 2 were produced by reducing mixtures of CuWO 4 and WO 3 with insufficient carbon black; then the obtained products were further reduced by hydrogen to remove the residual oxygen. This method provides a simple and low-cost route to prepare ultrafine W-10 wt pct Cu composite powders. The composite powders were sintered at different temperatures [1323 K (1050 °C), 1373 K (1100 °C), 1423 K (1150 °C), 1473 K (1200 °C), and 1523 K (1250 °C)] for 3 hours. A maximum densification of the obtained compact was achieved at a sintering temperature of 1523 K (1250 °C), with a relative density, Vickers hardness and thermal conductivity of the W-10 wt pct Cu composites of 97.8 pct, 365 HV and 165 W/m K, respectively.
研究领域:
材料科学
·
冶金工程
✓ 已验证
DOI
高影响因子
CELLULOSE
·
2021
·Vol. 28
·期 11
·7213-7225
·
IF 5.044
Zhang Jing,Bao Yan,Guo Mingyuan,Peng Zhenghua
Poor water solubility of cellulose acetate is a key factor limiting its application in leather finishing field. Herein, a self-emulsifying aqueous emulsion was synthesized by using cellulose diacetate (CDA) as the substrate, dimethylolbutyric acid (DMBA) as the hydrophilic agent, and hexamethylene diisocyanate (HDI) as the bridging agent. Because the flexible carbon chain of HDI has the advantages of easy bending and deformation, the problem of large steric hindrance and low reactivity of -OH during water-based CDA can be solved by using the method of converting reactive functional groups and transferring reactive sites. At the same time, the flexible molecule 1,4-butanediol (BDO) and propylene glycol polyether (N210) are used as chain extenders to increase the molecular stretch and curl ability by adjusting the ratio of molecular soft and hard segments, and improve emulsion stability and coating flexibility. And through the reaction of -NH 2 and -NCO on the surface of nano SiO 2 modified by KH550, the nano SiO 2 is evenly distributed in the CDA water-based polymer to improve the comprehensive performance of the emulsion coating. Thus the nano-SiO 2 modified cellulose acetate water-based polymer emulsion (SiO 2 /WCDA) is obtained for leather finishing. The emulsion particles show an oil-in-water (O/W) core–shell structure, and the average particle size and dispersion coefficient (PDI) of the particles are 88.79 nm and 0.150, respectively. The surface of the coating film is compact, flat, and hydrophobic, with the contact angle is 104.3 °. In addition, the coating film has good adhesion, water resistance, heat resistance, yellowing resistance, chemical resistance, flexibility and mechanical properties.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）