Journal of Physical Chemistry C
·
2020
·
IF 4.189
Meng Liu,Ying-Ying Wang,Yi Liu,Feng-Lei Jiang
Ligand exchange is a critical step for tuning the properties of quantum dots (QDs), as well as functionalization for wide applications. Previous studies have categorized X-, L-, and Z-types of ligands and classified the ligand exchange process accordingly. Many works have investigated the influences of ligand exchange on the optical properties of QDs. To date, however, the thermodynamic implications of ligand exchange are not well understood, and the mechanisms of distinct effects of the ligands of the same type are unclear. To address these issues, ligand exchange reactions of the oleate-capped CdSe QDs with alkylamines of different carbon chain length, namely, n-butylamine (C4Am), n-octylamine (C8Am), n-dodecylamine (C12Am), were investigated using 1H nuclear magnetic resonance (1H NMR) spectroscopy, fluorescence spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), etc. 1H NMR studies showed that the equilibrium constants (Keq) for the desorption of the Z-type ligand (cadmium oleate) from the surface of CdSe QDs, as promoted by the L-type ligands (alkylamines), were in the order of C4Am > C8Am > C12Am, presumably highlighting the small steric barrier of ligands with short carbon chain. In addition, the ligand exchange was studied by fluorescence titration at varied temperatures from a perspective of ligand adsorption following the desorption of cadmium oleate. The binding constants were of magnitude 103 M–1. A “two-step ligand exchange” (TSLE) model was developed to describe the ligand desorption–adsorption process with thermodynamic perspectives. The increased length of the carbon chain brought not only increasing steric barrier but also increasing van der Waals interactions, exhibiting a double-edged sword effect in ligand exchange. The ligand exchange with C8Am contributed the most negative value of ΔH and ΔS since the van der Waals interactions between C8Am and neighboring ligands were stronger than that for C4Am, whereas its steric barrier was weaker than that of C12Am. These demonstrated the importance of ligand–ligand interactions, relatively less documented in the previous studies, besides the predominance of the nanocrystal–ligand interactions. UV–vis absorption spectroscopic and fluorescence lifetime studies further showed that the ligand exchange with all three alkylamines affected optical properties of CdSe QDs to some extent. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) results showed that the ligand exchange process basically did not affect the crystal structure and core size of the CdSe QDs. Our work had proposed a conceivable mechanism for ligand exchange, elucidated the thermodynamic implications, and provided a reasonable guidance for selection of suitable ligands.
研究领域:
材料科学
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化学
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DOI
高影响因子
Journal of Energy Storage
·
2023
·
IF 9.4
Xiaoyin Cao,Lijuan Yang,Jia Zhang,Zhaoqi Zhu,Jiyan Li,Hanxue Sun,Weidong Liang,An Li
The fabrication of composite phase change materials (CPCMs) is significant for harvesting and converting solar energy. Hence, we first report novel CPCMs based on inorganic multi-shelled hollow spheres (MHS) via a facile hydrothermal method and calcination treatment. 1-Hexadecylamine (HDA) and Octadecylamine (ODA) were incorporated into MHS by a simple impregnation treatment to prepare CPCMs. Owing to its multi-shelled structure, the CPCMs have an outstanding ability of leakage resistance . In addition, the CPCMs themselves exhibit excellent solar absorption of up to 80 % without further surface modification. The thermal conductivity of the CPCMs containing HDA and ODA was increased by 1.03 times and 1.67 times by comparison with that of pure PCMs. The enthalpy of the as-resulted CPCMs is 207.6 J/g and 151.5 J/g, which is higher than most existing CPCMs, and the enthalpy of the CPCMs containing HDA and ODA after 100 times cycles can still attain 110.9 J/g and 104.7 J/g. Under 1sun irradiation, the light-to-thermal conversion efficiency of the CPCMs containing HDA and ODA was measured to be 90.0 % and 92.1 %, respectively. Taking advantage of its inherently physicochemical stability, superior light absorption and thermal conductivity and leakage resistance , scalable and cost-efficient fabrication process, such MHS-based CPCMs may have great potential for a wide variety of applications such as photothermal conversion, solar energy harvesting and storage, and so on.
研究领域:
材料科学
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能源材料
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太阳能转换
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热管理
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DOI
高影响因子
Journal of Physical Chemistry C
·
2019
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IF 4.309
Keyang Yin,Dandan Lu,Liping Wang,Quanxin Zhang,Junying Hao,Gaozhan Li,Hongguang Li
In the preparation of carbon dots (C dots) through pyrolysis, organic molecules with multiple functional groups are popular, and monosubstituted compounds, such as aliphatic amines, are used only as an auxiliary component. Here, we provide a strategy to transfer aliphatic amines and aliphatic aldehydes to C dots in the absence of any other reagent under mild conditions. In a typical experiment, C dots were facilely obtained by refluxing dodecylamine (C12–NH2) in chlorobenzene, which shows blue emission with wavelength-dependent characteristics. The C dots are soluble in a variety of organic solvents and can be further processed by either gel permeation chromatography or silica gel column chromatography, which gives highly pure C dots with absolute fluorescence quantum yield over 10%. The C dots are photoluminescent in the solvent-free state and can be used as fluorescent ink. They are also compatible with polymers such as poly(methyl methacrylate) and polydimethylsiloxane. Influence of the type of functional group was checked. Blue-emitting C dots were obtained as well by refluxing dodecanal in chlorobenzene, but using a compound bearing a carboxylic or hydroxy group only showed little success.
研究领域:
材料科学
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化学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2020
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IF 9.038
Ruilin Wang,Shiquan Liu,Shivani Bhardwaj Mishra,Hui Zhao
Silica species generated by the hydrolysis and condensation of tetraethyl orthosilicate (TEOS) could assemble with alkylamines to form silica gel . Herein, it was evidenced that part of the added amines, including butylamine (BA), octylamine (OA) or dodecylamine (DA), was protonated in the mixture of water and ethanol. Therefore, besides the hydrogen bonding between neutral silica species and the micelles composed of the non-protonated amines (Tanev and Pinnavaia, 1995), there existed strong electrostatic attraction between negatively charged silica species and the micelles composed of the protonated amines. This coexisting assembly mechanism could explain why the uncalcined BA- and OA-gels were millimeter-sized small blocks with large porosities and synthesized without waste water emission, while the uncalcined DA-gel was almost non-porous and formed via precipitation from its reaction medium. The uncalcined BA gel was proved to be efficient as a solid basic catalyst, replacing the commonly used ammonia solution which is easily volatilized and has a pungent smell, for the hydrolysis and condensation of TEOS to prepare silica microspheres.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2018
·Vol. 29
·期 13
·10864-10874
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IF 2.324
Shao Zhi,Zhuang Zhuang,Lin Haidan,Zhao Chengji
Here, a series of novel poly(ether ether ketone) containing sulfoalkylamine pendant groups (SNPEEK- x ) were synthesized by grafting copolymerization reaction. The chemical structure of SNPEEK- x was identified by 1 H NMR and the morphology of all films was measured by SAXS and TEM. The impedance varied for five orders of magnitude (from 10 7 to 10 2 Ω) as the relative humidity increasing from 11 to 97% RH. At the same time, all samples exhibited a fast response time of less than 3 s, outstanding repeatability and good long-term durability against high humidity. Especially, SNPEEK- x sensors displayed an extremely small humidity hysteresis in the impedance versus RH relationship during absorption and desorption processes. These essential properties of humidity sensors such as the impedance at various humidity, sensitivity, linearity and humidity hysteresis revealed that SNPEEK- x are suitable to be used as humidity sensors.
研究领域:
材料科学
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传感器技术
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产品关联
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
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2018
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IF 3.716
Shengqian Zhou,Jing Lin,Xiaofei Qin,Ying Chen,Congrui Deng
An improved ion chromatographic method including two elution procedures was proposed for the quantitative determination of atmospheric alkylamines in field atmospheric samples involving high levels of inorganic cations by using 18-crown-6 as mobile phase additive. When 18-crown-6 was added to the mobile phase, the retention times increased significantly for Na + , NH 4 + , K + and primary alkylamines but decreased for secondary and tertiary alkylamines due to the complexation with certain cations and interaction with both stationary and mobile phases of 18-crown-6. As a result, the separation of the cations was greatly promoted, which reduced the interference of peak distortion of overloaded inorganic cations on the quantitation of adjacent alkylamines. By using the presented method, five inorganic cations (Na + , NH 4 + , K + , Mg 2+ , Ca 2+ ) and six alkylamines (dimethylamine (DMAH + ), trimethylamine + diethylamine (TMAH + + DEAH + ), propylamine (MPAH + ), triethylamine (TEAH + ), ethanolamine (MEOAH + ) and triethanolamine (TEOAH + )) were effectively separated and determined, and the relative standard derivations (RSDs) of objective cations were all less than 1% for retention time and 3.1% for peak area (n = 9), respectively. The linearity was excellent for each cation (R 2 > 0.993) except for NH 4 + and TEOAH + showing a non-linear response (R 2 > 0.998 for theoretical non-linear fitting), and the detection limit of these cations were 0.03–1.19 ng. The proposed method was successfully used in the determination of both alkylamines and inorganic cations in ambient particulate matters and gaseous alkylamines in ceiling duct exhaust. The annual average concentrations of DMAH + , TMAH + + DEAH + and TEAH + were 15.56, 4.35 and 16.00 ng m −3 in PM 2.5 over Shanghai in 2013. The concentrations of gaseous DMA and TMA + DEA in ceiling duct exhaust reached a maximum of 940.0 and 112.7 μg m −3 , and were positively correlated with the human activity intensity, suggesting that human excreta emissions was a potential important source of atmospheric alkylamines in urban area of Shanghai.
研究领域:
环境科学
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分析化学
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产品关联
DOI
PubMed
高影响因子
LANGMUIR
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2017
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IF 3.833
Congxin Xia,Zhi Wang,Di Sun,Baolai Jiang,Xia Xin
A novel simple strategy for alkylamine-directed self-assembly of Weakley-type polyoxometalate (POM, Na9[EuW10O36]·32H2O, abbreviated to EuW10) to form three-dimensional nanoflowers has been successfully developed through the ionic self-assembly (ISA) method. For comparison, different molecular weights of alkylamines including diethylenetriamine, triethylenetetramine, and tetraethylenepentamine (TEPA) were selected to construct hierarchical nanostructures. Our results revealed that the morphologies and sizes of the nanostructures could be simply controlled by varying the molecular weights and concentrations of alkylamines. The fluorescent color of EuW10/TEPA nanoflowers changed compared with that of EuW10 owing to the varied symmetry degree of europium coordination in EuW10/TEPA nanoflowers. It is demonstrated that this effective self-assembly occurs mainly though the hydrogen bond and electrostatic interaction between EuW10 and TEPA. What’s more, the EuW10/TEPA nanoflowers after calcining showed excellent decomposition efficiency toward methylene blue dyes. Our results further confirmed that ISA method between small molecules and POM can provide a unique “bottom-up” strategy to construct novel structures with functional properties.
研究领域:
材料科学
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环境科学
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化学
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产品关联
DOI
PubMed
高影响因子
FIBERS AND POLYMERS
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2022
·Vol. 23
·期 10
·2740-2747
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IF 2.347
Zheng Jiaojiao,Zhang Hong,Cao Tianyu,Zhu Yuanyuan,He Lizhong,Li Jianwei,Chen Xudong,Qu Yinhu
Superhydrophobic surfaces by creating surface roughness followed by coating with low-surface-energy fluorinated materials have been intensively developed on cotton fabrics. However, exploring superhydrophobic surfaces with non-fluorine components and further improving their attachment with cotton fabrics is still challenging. Herein, we developed a superhydrophobic surface on cotton fabric by dip coating with hexadecylamine (HDA) modified copper nanowires (Cu NWs) based on the coordination between Cu atoms and amine groups. The HDA modified Cu NWs not only created surface roughness, but also decreased the surface energy, leading to a superhydrophobic cotton fabric with water contact angle of 164 °±2.0 °. Furthermore, ultrasonic washing and tape peeling tests exhibited the Cu NWs were adhered tightly to the surface of cotton fibers, owing to the strong hydrogen bond between amine groups on HDA molecules and hydroxyl groups on cotton fibers. In addition, the superhydrophobic cotton fabric showed excellent antifouling, oil-water separation and infrared reflection properties. It is believed that this facile method provide promising industrial applications for fabricating superhydrophobic surfaces on other substrates.
研究领域:
材料科学
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表面化学
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环境工程
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产品关联
DOI
高影响因子
International Journal of Coal Preparation and Utilization
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2016
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IF 0.855
Liang Shen,Huai-fa Wang,Bing-lin Guo,Hao Wang
Reverse flotation of Pingsuo thermal coal was investigated and it turned out that a large amount of DDA-HCL (dodecylamine hydrochloride) was needed in this process. Two fatty acids (dodecanoic acid and oleic acid) of different carbon chain lengths emulsified by DDA-HCL were used to compare with DDA-HCL in the experiments. Experimental results showed that the two emulsions had stronger collectivity than DDA-HCL. Dodecanoic emulsions had higher selectivity than OA (oleic acid) emulsions. The application of dodecanoic emulsions can obtain a lower ash content of the concentrate than DDA-HCL at the same collector dosage. And it can reduce DDA-HCL consumption greatly under the same concentrate ash content. Reverse flotation results of the two emulsions were also compared. The results indicated that the selectivity of dodecanoic emulsions dropped sharply when the amount of substance ratio of DDA-HCL and dodecanoic acid was less than 1:1.
研究领域:
矿物加工工程
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化学工程
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产品关联
DOI
高影响因子
ACS Nano
·
2023
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IF 17.1
Chuansheng He,Linlin Yang,Xiaohui Peng,Shangheng Liu,Jia Wang,Chengyuan Dong,Delin Du,Leigang Li,Lingzheng Bu,Xiaoqing Huang
Thickness regulation of transition metal hydroxides/oxides nanosheets with superior catalytic properties represents a promising strategy to enhance catalytic performance, but it remains an enormous challenge to achieve precise control, especially when it comes to the ultrathin limit (several atomic layers). In this work, a facile strategy of alkylamine-confined growth is proposed for the synthesis of thickness-tunable metal hydroxide/oxide nanosheets. Specifically, ultrathin cobalt hydroxide and cobaltous oxide hybrid (Co(OH)2-CoO) nanosheets (Co–O NSs) with a thickness in the range of 2–6 nm (5–13 atomic layers) are synthesized by using alkylamines with different carbon chain lengths as the ligand to modulate vertical coordination ability. Co–O NSs with a thickness of 2 nm (Co–O NSs-2 nm) exhibit excellent oxygen evolution reaction (OER) performance with an overpotential of 278 mV at 10 mA/cm2. The maximized number of active sites including oxygen vacancies, optimal adsorption strength, and the highest electrical conductivity are considered as the potential factors contributing to the excellent OER performance of Co–O NSs-2 nm. This work holds great significance for the precise thickness-tunable synthesis of transition metal layered hydroxide nanosheets with modulated and improved catalytic performance.
研究领域:
材料科学
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催化化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2025
·
IF 4
Ling Liu,Yizhe Zhu,Zitao Chai,Ruifen Zheng,Zhiqiang Zeng,Caiming Tang
This study developed a rapid and reliable liquid chromatography high-resolution mass spectrometry (LC-HRMS) method for the simultaneous determination of 8 alkylamines and 12 alkylamides in meat products. Sample preparation and instrumental conditions were optimized to achieve efficient extraction and accurate quantification. Meat samples were extracted with methanol-acetonitrile mixture (1:1, v / v ) using vortex-ultrasonication for 15 min, followed by evaporation and reconstitution prior to analysis. The mobile phases were ultrapure water containing 0.1% formic acid and acetonitrile, and a gradient elution program was employed. Mass spectrometric analysis was performed in positive electrospray ionization mode with full scan and data-dependent acquisition. Quantification was carried out using an internal standard method. The limits of quantification were 5 ng/g, and calibration curves showed good linearity. Recoveries ranged from 85.2% to 103.0% with relative standard deviations (RSDs) of 0.3-8.0%, and matrix effects ranged from 61.7% to 109.6% with RSDs of 0.2-10.3%. The method was successfully applied to meat samples collected from local markets, with concentrations of individual alkylamines and alkylamides ranging from below the detection limit to 13105.0 ng/g. Migration experiments indicated that alkylamines and alkylamides could transfer from plastic materials into meat, with migration extent increasing with the increase of contact time and temperature. Hydrophobic alkylamides migrated more rapidly in early stage, while some alkylamines continued to migrate at low temperatures, indicating that meat characteristics and contact conditions could significantly affect the migration. The developed method is suitable for the determination of alkylamines and alkylamides in meat products, and can provide a reference approach for assessing the potential migration and exposure risks of alkylamines and alkylamides.
研究领域:
分析化学
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食品科学
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毒理学
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食品安全
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药物代谢
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环境健康
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2014
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IF 2.538
Xuyu Yang,Tao Mei,Jia Yang,Changan Zhang,Meijiao Lv,Xianbao Wang
Functionalized reduced graphene oxide (RGO) was synthesized by modification of graphene oxide (GO) with octadecylamine (ODA), dodecylamine (DDA) and octylamine (OTA) and subsequent reduced by hydrazine hydrate . The successful grafting of alkylamine onto the RGO surface was confirmed by Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA), and the structure of alkylamine-functionalized graphene was characterized by means of XRD and Raman spectroscopy. UV–vis spectra showed that RGO–DDA and RGO–ODA are of equivalent solubility in organic solvents. For the potential application of the alkylamine functionalized-graphene on polyolefin matrix, the properties of functionalized-graphene/low density polyethylene (LDPE) nanocomposites were evaluated in this paper. Initial results showed that RGO–DDA/LDPE nanocomposites exhibited higher mechanical properties and thermal stability at the same content of alkylated graphene compared with the RGO–ODA/LDPE nanocomposites. Our work provides a new horizon to choose a compatilizer with appropriate alkyl chain lengths in the development of graphene/polyolefin nanocomposites.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
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