RSC Advances
·
2015
·Vol. 6
·期 8
·6504-6510
·
IF 3.84
Yaoquan Jiang,Yafei Zhao,Xin Feng,Jianhui Fang,Liyi Shi
The first use of nanocellulose extracted from bamboo fibers as a fibrous network skeleton and carbon dots derived from nanocellulose as guest fluorescent nanomaterials to construct a transparent, photoluminescent hybrid film is reported. The primary hydroxyls of nanocellulose are firstly converted to the carboxyl form by using tetramethyl-1-piperidinyloxy (TEMPO)-mediated oxidation to enhance the interfacial interaction with carbon dots and then to assemble heterogeneous network architectures through covalent bonding. The carbon dots derived from TEMPO-mediated oxidized nanocellulose display highly uniform spherical morphology with a narrow size distribution ranging from 6 nm to 11 nm. The resultant nanocellulose-based hybrid film has high transparency in bright field imaging and a strong blue luminescence under ultraviolet excitation. Furthermore, the biocompatible hybrid film extracted from the biomass exhibits excellent thermal stability and outstanding mechanical durability, which could be utilized as a substitute for petroleum-based film for diverse applications.
研究领域:
材料科学
·
生物化学
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高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2020
·Vol. 22
·期 6
·1-11
·
IF 2.132
Sun Tingting,Liang Huazhe,Liu Shaojie,Tang Erjun,Fu Cuiyan
Magnetic nanoparticles (MNPs) modified by polyamidoamine (PAMAM)-immobilized 2,2,6,6-tetramethyl-1-piperidinyl-oxyl (TEMPO) as recoverable catalysts for catalytic oxidation of polyethylene glycol were designed and prepared, which were expected to combine the advantages of easy recovery of MNPs and high activity of PAMAM-immobilized TEMPO. The catalysts of MNPs modified by PAMAM-immobilized TEMPO (MNPs-PAMAM-T) were characterized by Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analyzer (TGA), and transmission electron microscopy (TEM). The mean particle size of MNPs was about 10 nm. MNPs-PAMAM-T/NaBr/NaClO was used as catalytic system for catalytic oxidation of monomethoxy poly (ethylene glycol). The catalytic performances were affected by the loading amounts of TEMPO and PAMAM generations. It was shown that the catalyst with TEMPO loading of 5.198 mmol/g using G2.0 PAMAM-modified MNPs as carrier had the best catalytic performance, which could be up to 94% of the free TEMPO level. The efficient recovery of catalyst could be achieved by magnetic separation and the recycling performance was good.
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Applied Materials Today
·
2019
·
IF 8.013
Ozioma Udochukwu Akakuru,M. Zubair Iqbal,Chuang Liu,Jie Xing,Zhenni Wei,Zhenqi Jiang,Qianlan Fang,Bo Yuan,Elvis Ikechukwu Nosike,Jianbi Xia,Yinhua Jin,Jianjun Zheng,Aiguo Wu
Magnetic resonance imaging (MRI) signal intensities in tissues are usually enhanced by the injection of metal-based contrast agents (CAs) in patients. Some of these metal compounds have been linked to incurable nephrogenic systemic fibrosis and other neurological disorders, leading to their discontinuation. Herein, we report the design, synthesis, and characterization of a self-assembled metal-free CA which is based on an organic nitroxide radical (4-carboxy-TEMPO) compartmentalized in the biocompatible, biodegradable natural polymer, chitosan (CS), alongside folate targeting for in vivo tumor MRI. This extension conceivably heralds a new application for CS-TEMPO, which hitherto was used in macro-sizes as initiators for grafting CS to various polymers. Significantly, the folic acid (FA)-modified metal-free CA (CS-TEMPO-FA; average size ∼113 nm) is substantially benign, with no evidence of acute toxicity; it exhibits desirable pharmacokinetic profile, enhanced stability in highly reducing environments, high nitroxide loading (molecular relaxivity ∼18.56 mM −1 s −1 ), and effective tumor targeting. This latter characteristic ameliorates the non-specific uptake of CAs by normal cells. CS-TEMPO-FA nanoparticles demonstrate commensurate contrast enhancement of the tumor region up to 1 h post-injection when injected into 4T1 tumor-bearing mice, a contrast enhancement capability hitherto unattained by TEMPO-based CAs. This work points to CS-TEMPO-FA as a potential alternative to metal-based CAs as well as an active folate-targeted metal-free CA for long-term longitudinal tumor MRI which ameliorates the otherwise short in vivo lifetimes of typical organic radicals-based CAs.
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FIBERS AND POLYMERS
·
2022
·Vol. 23
·期 10
·2809-2819
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IF 2.347
Yang Yuhui,Chen Hongbin,Zhang Ruquan,Huang Jingjing,Bai Zhikui,Xiao Shili
The ferric ions sludge produced during pollutants degradation was an obstacle for large scale application of Fenton oxidation technology. Herein, we reported a facile method using 2,2,6,6-tetramethylpiperidine-1-oxygen radical (TEMPO)-oxidized cotton fabric as a substrate for anchoring Fe(II) ions to produce Fe(II)-anchored cotton fabric. The formation of Fe(II)-anchored cotton fabric was confirmed using EDS analysis and FTIR measurement. Bath experiments indicated that Fe(II)-anchored cotton fabric could Fenton oxidize rhodamine B (RhB) dye in a high efficient rate (95.9 %) within 60 min without second pollution. Fe(II)-anchored cotton could be reused without any physical/chemical treatment and its decolorization efficiency was retained at 89.9 % even after the third cycle. Moreover, the decolorization behavior of Fe(II)-anchored cotton fabric for the RhB solution was affected by H 2 O 2 dosage, Fe(II) ion content, and inorganic salts. Kinetic study indicated that the RhB decolorization process fits a pseudo-first order well and the sorption isotherm assessment revealed that the reactive sorption of RhB dye on Fe(II)-anchored cotton fabric fits the Freundlich model.
研究领域:
环境科学
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材料科学
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PLoS One
·
2013
·Vol. 8
·期 6
·e64722
·
IF 3.73
Fei Wang,Naimin Shao,Yiyun Cheng
In this study, the host-guest behavior of poly(amidoamine) (PAMAM) dendrimers bearing amine, hydroxyl, or carboxylate surface functionalities were investigated by paramagnetic NMR studies. 2,2,6,6-Tetramethylpiperidinyloxy (TEMPO) derivatives were used as paramagnetic guest molecules. The results showed that TEMPO-COOH significantly broaden the 1 H NMR peaks of amine- and hydroxyl-terminated PAMAM dendrimers. In comparison, no paramagnetic relaxation enhancement (PRE) was observed between TEMPO-NH 2 , TEMPO-OH and the three types of PAMAM dendrimers. The PRE phenomenon observed is correlated with the encapsulation of TEMPO-COOH within dendrimer pockets. Protonation of the tertiary amine groups within PAMAM dendrimers plays an important role during this process. Interestingly, the absence of TEMPO-COOH encapsulation within carboxylate-terminated PAMAM dendrimer is observed due to the repulsion of TEMPO-COO- anion and anionic dendrimer surface. The combination of paramagnetic probes and 1 H NMR linewidth analysis can be used as a powerful tool in the analysis of dendrimer-based host-guest systems.
研究领域:
化学
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材料科学
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生物物理学
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2025
·
IF 8.5
Zhonggeng Wang,Luzhu Fang,Sensen Ma,Xuejing Zheng,Jianfeng Wang,Yanyu Yang,Wanjie Wang,Yanxia Cao
Nanofibrillated cellulose (NFC) is widely utilized across various fields due to its excellent comprehensive properties. An important area of research focuses on developing high-performance composites by blending NFC with different media, including solvents and polymers. The dispersion of NFC within the medium plays a crucial role in determining the overall performance of these composites. Hansen Solubility Parameters (HSPs) are essential for assessing intermolecular interactions and predicting the dispersion of nanofillers. In this study, microcrystalline cellulose (MCC) was used as the primary raw material to prepare eight types of NFC using the TEMPO oxidation method. The dispersibility of these NFC variants in twenty-nine different solvents was evaluated through turbidity measurements, and MATLAB software was employed to fit and obtain the HSPs for each type of NFC. Further research revealed a significant inverse relationship between NFC diameter, which serves as an indicator of its size, and the dispersion parameter (δ D ) value. Additionally, as the -COOH content increased, the hydrogen bonding parameter (δ H ) value also increased. In contrast, no significant correlation was observed between the polar parameter (δ P ) value and the morphological structure of NFC. This research aims to expand the HSP database for nanomaterials, providing valuable guidance for selecting the most suitable medium for optimal NFC dispersion.
研究领域:
材料科学
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化学工程
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PubMed
高影响因子
CELLULOSE
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2013
·Vol. 20
·期 5
·2427-2437
·
IF 3.476
Yang Dong,Peng Xin-Wen,Zhong Lin-Xin,Cao Xue-Fei,Chen Wei,Sun Run-Cang
Cellulose nanocrystals (CNCs) have drawn tremendous attention because of their extraordinary physical and chemical properties as well as renewability and sustainability. In this work, after a range of pretreatments, such as freeze-drying, ball-milling, mercerization, N -methylmorpholine- N -oxide dissolution and ionic liquid dissolution, various CNCs with different crystalline properties and morphologies were obtained by hydrolysis or oxidation. XRD and AFM were used to determine the influences of pretreatments on the crystalline properties and morphologies of CNCs. New methods, i.e., specific pretreatments followed by sulfuric acid hydrolysis or 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidation, were developed to obtain sphere-like CNCs. It was found that sphere-like CNCs were more likely to be obtained from cellulose materials possessing high accessibility. Pretreatments produced cellulose with various crystallinities and polymorphs, and therefore changed the yields of CNCs and influenced their morphology. CNCs prepared by TEMPO oxidation generally had smaller size than the corresponding products obtained by sulfuric acid hydrolysis. In addition, for the dissolved/regenerated cellulose, TEMPO oxidation was a better method to yield sphere-like CNCs than sulfuric acid hydrolysis.
研究领域:
材料科学
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化学工程
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AATCC Journal of Research
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2021
·
IF 1.127
Sayed Waqar Azhar,Fujun Xu,Yiping Qiu
In recent decades, rational management of agricultural residues presented a new approach for extraction, characterization, and utilization of cellulose nanofibers (CNF). In this context, the valorization of flaxseed fibers, providing an annual yield of millions of metric tons, as an abundant sustainable fiber source, was carried out. The cleaned and ground raw material was delignified and bleached, followed by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)/NaBr/NaClO oxidization along with mechanical homogenization. The resulting extracted cellulose and cellulose nanofibers were characterized by various analytical methods. The overall yield of CNF based on the raw material was 31.2% ± 1.5%. This study explored a simple method for converting flaxseed fibers to fluorescent, high quality, nano-sized cellulosic precursors for novel applications in pharmaceutical and bio-composite applications.
研究领域:
材料科学
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生物工程
·
农业科学
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高影响因子
SOLAR ENERGY
·
2018
·
IF 4.374
Xichuan Yang,Weihan Wang,Yanyun Zhang,Licheng Sun
P-type doping is a rational strategy for the enhancement of hole transporting properties of the organic semiconductors as well as the device performance of organic photo-electric devices. We originally introduce a stable and solution processed p-type dopant based on N-oxoammonium salts termed 2,2,6,6-tetramethyl-1-oxopiperidinebromide salt (TEMPO-Br) for 2,2′,7,7′-tetrakis(N, N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene (Spiro-OMeTAD) based solid state dye sensitized solar cells (ssDSC). By introducing TEMPO-Br doped Spiro-OMeTAD and a commercialized D-π-A sensitizer into ssDSCs, a promising device performance of 6.83% is achieved under simulated AM 1.5G solar irradiation (100 mW cm −2 ), which is significantly better than the control devices (∼1.7 times). The doping effect of TEMPO-Br on the photophysical and electrochemical properties of Spiro-OMeTAD, solid state device performance, cationic dye regeneration kinetics and preliminary long-term stability have been systematically investigated. This work indicates a potential application of N-oxoammonium salts as chemical P-type dopants for triphenylamine based hole transporting materials in solid state photo-electric devices.
研究领域:
材料科学
·
光电化学
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高影响因子
ACS Applied Polymer Materials
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2021
·
IF 4.089
Tianyou Chen,Zihao Wang,Wei Xiao,Changfeng Yi,Zushun Xu
Transformation of multifunctional homogeneous catalysts to the corresponding heterogeneous catalytic systems makes catalytic reactions interesting from both economic and environmental points of view. Here, we have devised a controllable and efficient strategy for the preparation of supported multifunctional catalysts by taking the Cu/2,2,6,6-tetramethyl-1-piperidine-N-oxyl (TEMPO) catalytic system as an example. Polystyrene-supported Cu/TEMPO catalysts were, for the first time, prepared via nanoprecipitation of polymers in water and efficient for aerobic oxidation of benzyl alcohol (BnOH). Cooperative behaviors could be regulated by precise control of local concentrations of functional groups. We have demonstrated that the incorporation of functional groups into polystyrene supports can make better use of catalytic components, resulting from confinement-enhanced cooperation. This strategy provides access to build more efficient multifunctional heterogeneous catalysts through establishing structure–activity relationships.
研究领域:
化学工程
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材料科学
·
催化化学
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ENVIRONMENTAL RESEARCH
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2025
·
IF 7.7
Dongdong Liu,Shun-xin Chen,Runkai Wang,Lin Li,Jiangyan Ji,Tong Wu,Kunlin Ke,Fei Chai
Enrofloxacin (ENR), characterized by its remarkable stability and resistance to degradation, has become a significant contaminant in aquatic ecosystems. In this study, a CNC/UiO-66(Fe) composite was synthesized via a one-step hydrothermal method, and response surface methodology (RSM) was employed to optimize the key experimental conditions for the efficient removal of ENR from aqueous solutions. The incorporation of cellulose nanocrystals (CNC) improved the dispersibility and stability of UiO-66, and significantly enhanced the crystallinity of the material, as confirmed by XRD analysis. Iron (Fe) doping introduced additional active sites and defects, synergistically enhancing the overall adsorption capacity. The composite exhibited a high BET surface area of 1294.81 m 2 /g and a well-developed porous structure. The adsorption process was spontaneous and exothermic, fitting well with both the pseudo-second-order kinetic model and the Langmuir isotherm model. Under alkaline conditions, the material showed excellent adsorption performance, with a theoretical maximum adsorption capacity of 275.84 mg/g for ENR at 25°C and pH 10. The adsorption mechanism involved multiple synergistic interactions, including electrostatic attraction, hydrogen bonding, π-π stacking, metal coordination, and pore filling. Furthermore, CNC/UiO-66(Fe) exhibited excellent stability and reusability, retaining over 80% of its removal efficiency after five cycles. This study provides an effective and sustainable approach for remediating antibiotic contaminants in aquatic environments.
研究领域:
环境科学
·
材料化学
·
水处理技术
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纳米材料
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吸附工程
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PubMed
高影响因子
Industrial Chemistry & Materials
·
2026
·
IF 15.7
Meijuan Cao,Xiaopei Wu,Dongdong Qiu,Shouzheng Jiao,Jian Sun,Jie Zong
Improving the interfacial interaction between conductive polymers and fiber substrates is essential for developing high-performance flexible supercapacitor electrodes. Herein, a simple and scalable approach is reported to modify cotton fibers via TEMPO-mediated oxidation, introducing carboxyl groups onto the fiber surface to produce carboxylated cotton fibers (C-CF). These functional groups significantly enhance the affinity between the fiber substrate and conducting polymers. Sequential in situ polymerization of polyaniline (PANI) and polypyrrole (PPy) on C-CF results in a well-integrated composite structure with improved active material loading and optimized multi-scale pore architecture (mesoporous channels together with a preserved open macroporous fiber network). Compared with unmodified fibers, the PPy/PANI/C-CF electrodes exhibit higher porosity, stronger interfacial bonding, and enhanced electrochemical activity. The symmetric flexible supercapacitor exhibits an areal capacitance of 102 μF cm−2 and a mass-specific capacitance of 85 mF g−1 at an operating voltage of 1.0 V, with an active material loading of 1.2 mg cm−2. The optimized electrode achieves a specific capacitance of 911 F g−1 at a current density of 2 mA cm−2 and maintains 79.08% capacitance after 1000 cycles, demonstrating cycling stability. This work highlights the effectiveness of fiber surface functionalization via TEMPO oxidation in improving electrode structure and performance, offering a promising strategy for flexible energy storage applications.
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