EUROPEAN POLYMER JOURNAL
·
2023
·
IF 6
Yuanzhen Xu,Mengru Zhang,Yuanyuan Pang,Tianyue Zheng,Chun Tian,Zhen Wang,Jingling Yan
Colorless polyimide (CPI) copolymers were synthesized by one-step or two-step methods, using 2,2′-bis(trifluoromethyl)benzidine (TFMB), 2,2′,3,3′-biphenyltetracarboxylic dianhydride (3,3′-BPDA), and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (4,4′-BPDA) as the monomers . These polymers exhibited a d -spacing value of 5.7–6.7 Å, and their d -spacing values increased while the intensity of π-π stacking interactions decreased with the increase of 3,3′-BPDA/TFMB contents. The solubility of the copolymers were gradually enhanced as the increase of 3,3′-BPDA/TFMB contents. Their coefficients of thermal expansion and glass transition temperatures increased with 3,3′-BPDA/TFMB contents, ranging from 15 to 68 ppm K −1 and 300 to 359 °C, respectively. These polymers exhibited excellent optical transparency ( λ 0 < 390 nm, T 450 > 83.2%, and b* < 4). CPI-4 and CPI-5 with 40 mol% and 20 mol% of 3,3′-BPDA/TFMB contents exhibited well-balanced solution processability and physical properties. The CPI copolymers can be potentially used in optical and optoelectronic fields owing to their desirable overall properties.
研究领域:
材料科学
·
聚合物化学
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Liang Bai
Salbutamol, clenbuterol, ractopamine and albuterol have the effect of promoting protein synthesis and increasing muscle mass. Despite that these substances are banned or restricted in animal husbandry in many countries, some farmers still use them illegally to improve profits. Athletes can test positive for stimulants after ingesting food with these drug residues. In this study, the electrochemical behavior of salbutamol, clenbuterol, ractopamine and albuterol were investigated with carbon nanotubes modified glassy carbon electrodes. The linear detection range and detection limit of four stimulants were studied under optimal conditions.
研究领域:
分析化学
·
药物检测
·
食品安全
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS CHEMISTRY
·
2011
·Vol. 21
·期 29
·10894-10902
·
IF 5.101
Wenbin Niu,Suli Wu,Shufen Zhang
Here we elucidate the “cooperative effect” of carboxylic acid/amine on the size, shape, and multicolor output of fluoride upconversion nanoparticles (UCNPs) utilizing the amidation reaction. During the synthesis of NaYF4 UCNPs using oleic acid (OA) and octadecylamine (OM) as ligands, the evolution of the reaction solution was monitored by FT-IR and proton nuclear magnetic resonance (1H-NMR) spectroscopy. It is shown that N-octadecyloleamide (OOA) was formed and tightly bonded to the surface of the fluoride UCNPs. FT-IR and 1H-NMR analyses point towards a two-step OOA formation mechanism where OA initially reacted with OM to form an acid–base complex (C17H33CO2− +NH3C18H37) in reaction mixture, which further transformed into OOA before the nucleation of fluoride UCNPs at elevated temperature. Importantly, we find that the interaction of OOA with the surfaces of the fluoride UCNPs was stronger than that of OM, and that OOA could strongly quench the green-emitting levels of excited Er3+ ions. A series of control experiments and analyses demonstrate that OOA was not only responsible for the control of the size and shape of NaYF4: 20% Yb, 2% Er UCNPs, but also for the multicolor tuning of them. Those observations reveal that the “cooperative effect” between carboxylic acid and amine results from the amidation reaction and its product. This paper provides us with some new deep insights into the “cooperative effect” of carboxylic acid and amine during the synthesis of inorganic nanoparticles under thermolysis. Furthermore, other lanthanide-ion doped fluoride UCNPs with controlled size, shape and multicolor output can also be obtained in the same way.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 13
·10381-10389
·
IF 2.22
Xie Houpeng,Yu Qijian,Mao Jie,Wang Sui,Hu Yufang,Guo Zhiyong
Flexible strain sensors, based on their good electrical conductivity and strain sensitivity, are widely used in wearable health monitoring, sensitive tactile information display and multi-functional robot skin. However, it is still a challenge for wearable devices to prepare conductive hydrogel with flexibility, high strain, high sensitivity and biocompatibility. Herein, we designed an interpenetrating network conductive composite hydrogel, which composed with polyaniline, double bond modified chitosan and acrylamide, has excellent strength and toughness due to its unique physically and chemically cross-linked double network. The obtained hydrogel exhibited good tensile strength (0.3 MPa), high electrical conductivity (6.97 S/m) and strain sensitivity (gauge factor 15.9). The results showed that the strain sensor could detect the movement of human joints through electrical signals, and had good stability and reproducibility, which indicated that it was expected to be used in wearable health monitoring and multi-functional robot skin.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
DOI
高影响因子
POLYMER COMPOSITES
·
2023
·Vol. 44
·期 8
·4495-4508
·
IF 5.2
Ping Han,Susu Zhang,Shaokai Hu,Ying Yu,Shaolong Han,Haoyu Wang,Jianfa Wang,Gang Wei,Zheng Gu
Polymer composites with tailored structure and enhanced properties and functions have attracted great attentions due to their wide applications in materials science, nanotechnology, and engineering science. In this work, we demonstrate the innovative concepts of fabricating both gradual “rigid-flexible” and alternate “rigid-flexible” structures, which are achieved by altering the grafting sequence of flexible polyethyleneimine with high flexibility and polydopamine with suitable rigidity. Then, the effect of different rigid-flexible structures on the structure and properties of the carbon fiber-epoxy (CF/EP) composites are studied. It is found that the composites reinforced by the alternate rigid-flexible polymer layer possess superior interfacial effects and mechanical properties. Compared with the CF/EP without polymer layer modification, the rigid-flexible layer contributes to about 80.3% and 167.3% on the interfacial shear strength and the impact strength of final composites. These great improvements are attributed to the complex crack propagation path, more energy consumption, wider interface region, higher wettability, as well as strong physical and chemical interactions. This work provides practical and scalable potentials for regulating the structure and functions of the CF-reinforced polymer composites by optimal interfacial design.
研究领域:
材料科学
·
纳米技术
·
工程科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Siyu Chen,Guodong Meng,Bo Kong,Bing Xiao,Zhengdong Wang,Ziang Jing,Yushuan Gao,Guanglei Wu,Hong Wang,Yonghong Cheng
Crosslinked structure is proved to be efficient to improve breakdown strength ( E B ), thermal stability and charge-discharge efficiency ( η ) of polymer film capacitors, which is of great interest for their application in electric power systems and electrical automobile industry. However, highly crosslinked molecular networks usually lead to weak polarization ability of polymer, which greatly restrict their energy storage density ( U d ). To improve polymers’ high-field polarization ability while guaranteeing their E B and thermal stability, we propose the asymmetric molecular chain structure in crosslinked network of epoxy resin by attaching ring-like alicyclic amine (ACA) and linear polyether amine (PEA) on phenol via Mannich reaction. The film exhibits high U d up to 9.12 Jcm −3 at 550 MVm −1 and ambient temperature with 90% efficiency, which is a record high value for U d among single-layer polymer under the same condition. At 200 MVm −1 and 120 °C, a future operating condition towards electric-vehicle applications, prepared film still exhibits U d of 1 Jcm −3 with 90% efficiency, which is twice of the state-of-the-art BOPP. The results prove that the asymmetric ACA-PEA structure can greatly improve U d of crosslinked polymer film while maintaining superior energy storage efficiency at high temperature. This work paves a new way for the material design of high-performance polymer film capacitor.
研究领域:
材料科学
·
电气工程
✓ 已验证
DOI
高影响因子
CARBON
·
2012
·Vol. 50
·期 8
·2810-2815
·
IF 5.378
Yongqiang Dong,Ruixue Wang,Hao Li,Jingwei Shao,Yuwu Chi,Xiaomei Lin,Guonan Chen
Polyamine-functionalized carbon quantum dots (CQDs) with high fluorescence quantum yield (42.5%) have been synthesized by the low temperature (<200 °C) carbonization of citric acid with branched polyethylenimine (BPEI) in one simple step. The obtained BPEI–CQDs are spherical graphite nanocrystals (average 6.2 nm in size) capped with abundant BPEI at their surfaces. It is the first report that CQDs are both amino-functionalized and highly fluorescent, which suggests their promising applications in chemical sensing.
研究领域:
分析化学
·
纳米材料
·
生物传感
·
荧光成像
·
分子探针
✓ 已验证
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2021
·
IF 7.46
Jiangwei Ma,Huiqing Fan,Zhexin Li,Yuxin Jia,Arun Kumar Yadav,Guangzhi Dong,Weijia Wang,Wenqiang Dong,Shuren Wang
The flexible room-temperature gas sensors are highly desirable to apply in wearable and portable equipment owing to their wearability. The research mainly focuses on the gas-sensing materials and few studies paid attention to the conjunction between flexible substrates and sensing materials. In this work, the polyethylene terephthalate (PET) fibers substrate is modified by ethylenediamine (EDA) to expose the amino group on the surface (PET-NH 2 ). This method is simple, cost-efficient, and easy to operate. The positively charged amino group could interact with negatively charged carboxyl (−COOH) of multi-walled carbon nanotubes (MWCNTs) by electrostatic attraction. The EDA treatment on PET effectively strengthens the connection between the flexible PET substrate and gas sensing materials with carboxyl as evidenced by SEM images. After the in situ polymerization process, the polyaniline (PANI) is successfully decorated on the MWCNTs. The fabricated PET-NH 2 -MWCNTs/PANI sensor exhibits strongly enhanced ammonia (NH 3 ) sensing performance as compared to the PET-MWCNTs/PANI sensor without the EDA treatment. The results suggest that the EDA treatment is an effective method to conjunct between flexible substrates and sensing materials, which shows great potential in the field of flexible gas sensors.
研究领域:
材料科学
·
传感器技术
✓ 已验证
DOI
高影响因子
MACROMOLECULAR RESEARCH
·
2017
·Vol. 26
·期 1
·9-12
·
IF 1.405
Zhang Rongli,Fan Xiaoxia,Xu Xiaofang,Lv Jingjing,Jin Zhenzhen,Hao Hui,Zhang Cuige
Dopamine modified γ -polyglutamic acid ( γ -PGA-DA) copolymer and melamine (Mel) can self-assemble into Mel/ γ -PGA-DA micelles via weak intermolecular interactions in aqueous solution containing small amount of methanol. When Mel/ γ -PGA-DA micellar solution was cast on the surface of formvar stabilized with carbon support films, the lotus-like nano-architectures were formed on the surface of substrate via hierarchical assembly of micelles. The size of lotus-like nanoarchitectures was approximately 200 nm×500 nm. The possible driving forces for hierarchical assembly of micelles were the solution fluid and interaction between micelles. The hierarchical assembly of micelles was similar to the fractal aggregation of inorganic particles and a possible reason was discussed.
研究领域:
材料科学
·
纳米技术
·
化学
✓ 已验证
DOI
高影响因子
Catalysts
·
2023
·Vol. 14
·期 1
·23
·
IF 3.9
Zi-Han Zhang,An-Qi Wang,Bao-Di Ma,Yi Xu
The effective synthesis ofN-benzyl cyclo-tertiary amines using imine reductase, key components in natural products and pharmaceutical synthesis, is a green approach. Traditional methods faced challenges with enzyme activity and selectivity. This study focused on enhancingMesorhizobiumimine reductase (MesIRED) for betterN-benzyl cyclo-tertiary amine production. Through alanine scanning and consensus mutation, 12 single-siteMesIRED mutants were identified from 23 candidates, showing improved conversion ofN-benzylpyrrolidine andN-benzylpiperidine. Notably, mutants from I177, V212, I213, and A241 significantly boosted conversions. The best-performing mutant forN-benzylpyrrolidine,MesIREDV212A/I213V(M1), increased conversion from 23.7% to 74.3%. ForN-benzylpiperidine,MesIREDV212A/I177A/A241I(M2) enhanced conversion from 22.8% to 66.8%. Tunnel analysis revealed M1 and M2 have more efficient tunnels for larger product movement compared to wild-typeMesIRED. Using recombinantE. colicoexpressingMesIRED and glucose dehydrogenase (GDH), high conversions were achieved: 75.1% forN-benzylpyrrolidine (M1) and 88.8% forN-benzylpiperidine (M2). A preparative experiment resulted in 86.2% conversion and 60.2% yield forN-benzylpiperidine. This research offers an efficient method for engineering IRED, significantly improving conversion and selectivity forN-benzyl cyclo-tertiary amines, aiding drug synthesis and providing insights into rational design of other enzymes.Keywords:imine reductase;N-benzyl cyclo-tertiary amines;alanine scanning;consensus mutation;whole-cell biocatalysis;coexpression
研究领域:
生物化学
·
酶工程
·
药物合成
✓ 已验证
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Lingyuan Wang,Lanfeng Hui,Weiyin Su
We prepared super-hydrophobic nanocellulose films using a non-toxic octadecylamine/polydopamine system. Octadecylamine, a low surface energy material, was used to provide hydrophobic alkyl long chains. Polydopamine was produced by dopamine under alkaline conditions, creating an adhesive substance, which reinforced the hydrophobic long chains and increased the surface roughness of nanocellulose. The effects of reagent concentration, reaction temperature, and reaction time on hydrophobicity were then investigated. The results showed that with a 1:1 mass ratio of nanocellulose to octadecylamine, and reacting at 60 °C for 4 h, the contact angle of the obtained composite membrane reached 168.2°. Scanning electron microscope images revealed that the modified nanocellulose had a smaller particle size and more uniform distribution, which effectively improved the hydrophobicity of the nanocellulose. Thus, the green preparation of superhydrophobic films with high-temperature resistance and wear resistance was realized, which contributed to the high-value utilization of nanocellulose.
研究领域:
材料科学
·
纳米技术
·
表面化学
✓ 已验证
DOI
高影响因子
ORGANIC & BIOMOLECULAR CHEMISTRY
·
2022
·Vol. 20
·期 15
·3201-3210
·
IF 3.89
Lin Chen,Wei Liang
Michael/ammonolysis cascade reactions between cyclohexane-1,3-dione-derived enaminones and olefinic azlactones via phase-transfer catalysis have been developed. This method provides rapid access to a suite of architecturally complex and diverse quinoline-2,5-diones bearing a secondary amide group at the C-3 position in moderate to excellent yields (53–94%) and with excellent diastereoselectivities (>99 : 1 dr in most cases). The achievement of a preparative-scale reaction and the diverse product derivatization that can be obtained highlight the application potential of this protocol both in academic and industrial settings. An investigation of the reaction mechanism implies that tetrabutylammonium hydroxide may be the actual catalyst during this cascade reaction.
研究领域:
有机化学
·
药物化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）