ChemCatChem
·
2019
·Vol. 12
·期 3
·903-910
·
IF 4.495
Li Zhao,Song Shi,Meng Liu,Chen Chen,Guozhi Zhu,Jin Gao,Jie Xu
Graphical It's good for the microenvironment : Hexagonal mesoporous silicas with hydrophobic microenvironment modified by phenyl group was used to mimic the enzymes with Co 3 O 4 incorporated as active sites, the pore hydrophobic environment had an enhancement in the adsorption of ethylbenzene and in turn improved the catalytic selective oxidation activity than the hydrophilic one. Microenvironments in enzymes play crucial roles in controlling the activities of active centers. Here, hexagonal mesoporous silicas (HMS) with hydrophobic microenvironment was used to mimic the enzymes on the hydrocarbon oxidation with cobalt oxides incorporated as active sites. The variation of the structure and surface properties of the materials with phenyl group incorporation and the state of the supported cobalt oxides were carefully studied. It showed that cobalt oxides presented as Co 3 O 4 distributed evenly among the support, and the catalytic microenvironment was modified by the neighboring phenyl groups to be hydrophobic. This novel catalyst showed enhancement in the adsorption of ethylbenzene and in turn promoted the catalytic conversion than the hydrophilic one. 55.1 % conversion of ethylbenzene and 86.1 % selectivity for acetophenone could be obtained at 393 K for 6 h under 1.0 MPa of O 2 with free solvent. Hydrophobic microenvironment of pore surface was considered as an important factor for the better catalytic activity.
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BIOSENSORS & BIOELECTRONICS
·
2018
·
IF 8.173
Yunfei Tang,Yun Chai,Xiaoqiang Liu,Lele Li,Liwei Yang,Peipei Liu,Yanmei Zhou,Huangxian Ju,Yunzhi Cheng
In this work, a CuS-TiO 2 heterojunction composite was prepared by dispersedly depositing CuS nanoparticles on TiO 2 nanospheres surface with a hydrothermal method , and was then used to construct a photoelectrochemical (PEC) aptasensor for sensitive detection of microcystin-LR (MC-LR) in aquatic environment. The energy bands of CuS nanoparticles and spherical anatase TiO 2 were well matched, which enhanced the photo-to-current conversion efficiency. The composite exhibited the enhanced visible light absorption , the improved separation of photo-generated charges, and the reduced self-aggregation of CuS nanoparticles, leading to the enhanced photocurrent response. The PEC aptasensor was constructed by immobilizing CuS-TiO 2 composite on ITO electrode with chitosan film that further covalently bound aminated aptamer. After the target, microcystin-LR (MC-LR) as an analyte model, was captured by the aptamer on the aptasensor, it could be oxidized by the photo-generated hole to impede the electron-hole recombination and further amplify the photocurrent. The PEC aptasensor showed superior analytical performance for MC-LR with a linear range of 5.0 × 10 −5 nM to 250 nM and a detection limit of 2.0 × 10 −5 nM. The detection results with the aptasensor for practical water samples indicated its promising application in environmental monitoring.
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BIOSENSORS & BIOELECTRONICS
·
2018
·
IF 8.173
Xiaoqiang Liu,Peipei Liu,Yunfei Tang,Liwei Yang,Lele Li,Zhichong Qi,Deliang Li,Danny K.Y. Wong
In this work, a sensitive photoelectrochemical aptasensor was developed for kanamycin detection using an enhanced photocurrent response strategy, which is based on the surface plasmon resonance effect of gold nanoparticles deposited on a 3D TiO 2 -MoS 2 flower-like heterostructure . A significant aspect of this development lies in the photoelectrochemical and morphological features of the unique ternary composite, which have contributed to the excellent performance of the sensor. To develop an aptasensor, mercapto-group modified aptamers were immobilised on the photoactive composite as a recognition unit for kanamycin. The TiO 2 -MoS 2 -AuNP composite was demonstrated to accelerate the electron transfer , increase the loading of aptamers and improve the visible light excitation of the sensor. Under optimal conditions, the aptasensor exhibited a dynamic range from 0.2 nM to 450 nM of kanamycin with a detection limit of 0.05 nM. Overall, we have successfully synergised both the electrical and the optical merits from individual components to form a ternary composite, which was then demonstrated as an effective scaffold for the development of PEC biosensors.
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Nanoscale
·
2018
·Vol. 10
·期 23
·11211-11221
·
IF 7.233
Jiacong Xu,Yanqin Miao,Jingxia Zheng,Hua Wang,Yongzhen Yang,Xuguang Liu
First, oleophilic carbon dots (CDs) with a fluorescence quantum yield (QY) of 41% were synthesized by a one-pot microwave-assisted carbonization method. Then, CD-based electroluminescent light emitting diodes (CD-LEDs) were prepared. The impact of CD aggregation on the brightness of CD-LEDs was studied. The results show that, to some extent, with the decrease of the aggregation of the CD film, the luminescence quenching of the CD-LEDs gradually decreased, and the luminance of the CD-LEDs gradually increased. Hence, in order to improve the dispersion of CDs and reduce the aggregation of CDs and the luminescence quenching of the devices, host–guest doping was adopted to effectively improve the brightness of CD-LEDs. In this work, the yellow emission of the doped devices is mainly derived from the direct carrier trapping on CDs. Moreover, white and yellow CD-LEDs were obtained from the same oleophilic CDs by tuning the structure of the devices. The white CD-LEDs exhibit a high color rendering index (CRI) of 83 with a luminance of 455.2 cd m−2. The yellow CD-LEDs show the maximum brightness of 339.5 cd m−2 and excellent color stability. The results show that the luminescence quenching of CD-LEDs was resisted and the brightness of CD-LEDs was improved by using host–guest doping.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Xiaojie Yang,Xueqin An
An in-situ synthesis method for loading Carbon Dots (CDs) on the surface and the inner cavities (lumens) of akund fibres has been presented. CDs were successfully loaded on the lumens of akund and AgNPs were also synthesized on the inner surface of fibres by using CDs on the surface of akund as reductant. The inner and outer surface morphology of akund-CDs and akund-CDs/AgNPs were obtained by using scanning electron microscope (FESEM). The fluorescence (FL) properties of CDs on the inner surface of akund-CDs and akund-CDs/AgNPs were compared by using confocal laser scanning microscopy (LSCM) and it showed that the FL intensity of CDs on akund-CDs was much stronger than that on akund-CDs/AgNPs. The microstructures of CDs on akund-CDs and akund-CDs/AgNPs were also probed by using time-resolved FL spectra for the first time, and the results showed that the microstructures of CDs on akund-CDs and akund-CDs/AgNPs were different. The FL property, load capacity, stability, antioxidant activity and washability of akund-CDs synthesized by different methods were also measured, and it was found that the in-situ method was much better than the traditional simple soaking method. This work suggested a promising approach to load nanoparticles on the lumens of akund, which endows akund with many functions to be applied in textile industry.
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APPLIED SURFACE SCIENCE
·
2013
·
IF 2.112
Xiang F. Geng,Xing Q. Hu,Ji J. Xia,Xue C. Jia
A series of novel di-hydroxyl-sulfate-betaine-type zwitterionic gemini surfactants of 1,2-bis[ N -ethyl- N -(2-hydroxyl-3-sulfopropyl)-alkylammonium] alkyl betaines (DBA s – n , where s and n represent the spacer length of 2, 4 and 6 and the hydrocarbon chain length of 8, 12, 14, 16 and 18, respectively) were synthesized by reacting alkylamine with sodium 3-chloro-2-hydroxypropanesulfonate (the alternative sulphonated agent), followed by the reactions with а , ω -dibromoalkyl and then ethyl bromide. Their adsorption and aggregation properties were investigated by means of equilibrium surface tension, dynamic light-scattering (DLS) and transmission electron microscopy (TEM). DBA s – n gemini surfactants showed excellent surface activities and packed tightly at the interface. For example, the minimum CMC value for DBA s – n series was of the order of 10 −5 M and the surface tension of water can be decreased as low as 22.2 mN/m. It was also found that the aggregates of DBA s – n solutions were significantly dependent on their hydrocarbon chain lengths. The aggregates changed from vesicles to entangled fiber-like micelles as the chain length increased from dodecyl to tetradecyl.
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EUROPEAN POLYMER JOURNAL
·
2014
·
IF 3.242
Chanjuan Tan,Jun Peng,Weihong Lin,Yuxiu Xing,Kai Xu,Jiancheng Wu,Mingcai Chen
Cellulose nanocrystals (CNCs), surface-modified by grafting long alkyl chain amine onto carboxylated CNCs, have been applied as novel nanofillers to prepare nanocomposite films of poly(ethylene-co-vinylacetate) (EVA) through solution casting technique. The robust amide linkages imparted hydrophobicity to the nanocrystal surface and allowed for a better dispersion of CNCs within the EVA matrix. Atomic force microscopy (AFM) surface images and polarized optical micrographs showed that the nanocrystals were randomly oriented in the plane of the EVA film. To achieve the alignment of anisotropic nanofillers, we carried out mechanical shear experiments at an elevated temperature well above the glass-transition temperature of matrix polymer. Hot-pressing and hot-stretching resulted in preferential reorientation of nanocrystals, but not along the shear direction, which is related to the combined actions between the external tension and intermolecular interaction of amide-modified CNC during shear processing. As a result, external mechanical stress transferred from the matrix to the particles, leading to a preferential orientation of the latter. Mechanical and water vapor barrier properties were found to be drastically enhanced. The amide-based CNC/EVA showed high level of elongation at break (up to 85% retention of the initial values). These enhancements were tentatively attributed to the strong interaction occurring at the interface between CNC amide and the EVA polymer.
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Journal of Materials Chemistry A
·
2014
·Vol. 3
·期 2
·600-607
·
IF 0
Hanxing Chen,Ming Wen,Zaidi Huang,Qingsheng Wu,Jiali Liu,Teng Tu
Highly active Cu@ZnO brush-like nanostructures have been successfully synthesized through the heteroepitaxial growth process of ZnO branched nanorods (NRs) based on Cu core nanowires (NWs), and used for the evaluation of selective catalytic degradation for polycyclic aromatic compounds. The resultant Cu@ZnO nanobrushes, with the main diameter of ∼500 nm, consist of Cu core NWs with diameter of ∼50 nm and outer ZnO branch NRs shells with thickness of ∼250 nm. The as-designed Cu@ZnO nanobrushes exhibit high performance for the selective catalytic degradation of polycyclic aromatic compounds. Nearly 90% conversion with the reaction rate constant (k) of 0.012 min−1 can be achieved for anthracene, while only about 50% and 10% conversions are shown for phenanthrene and naphthalene, respectively. Besides the highly efficient transportation of electrons, Cu NWs have strong capacity for oxygen activation which results in the gathering of negative charges and rich chemisorbed oxygen onto the surface, which is responsible for the high catalytic efficiency of Cu@ZnO nanobrushes toward the selective degradation of anthracene.
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AUSTRALIAN JOURNAL OF CHEMISTRY
·
2014
·Vol. 68
·期 5
·806-813
·
IF 1.644
Liandong Feng,Xinyu Hu,Aming Xie,Hao Yu,Yangyang Liu,Jianfa Zhang,Wei Dong,Liandong Feng,Xinyu Hu,Aming Xie,Hao Yu,Yangyang Liu,Jianfa Zhang,Wei Dong
Polymer vesicles have attracted extensive interest for a variety of biomedical applications. Herein, novel polymer vesicles are prepared by the self-assembly of amphiphilic polyethyleneimine-g-poly(disulfide amine)-g-polyethyleneimine (PEI-g-PSSA-g-PEI) for gene delivery. To investigate the effect of hydrophobicity on transfection efficiency, a small series of PEI-g-PSSA-g-PEI were prepared under uniform conditions containing PEI fragments of the same molecular weight. The hydrophobicity of PEI-g-PSSA-g-PEI was adjusted by varying the hydrophobic content in the poly(disulfide amine) backbone and by choosing hydrophobic monomers ranging in length from C12 to C16. The hydrophobicity of polymers was also related to DNA binding affinity. Polymer vesicles obtained from the water-insoluble polymers condensed with DNA into polyplexes with sizes below 200 nm and surface charge ranging from +10 to +35 mV that were suitable for cell endocytosis. DNA polyplexes exhibited an inverted hexagonal structure, observed by transmission electron microscopy. The results of in vitro transfection demonstrate that the hydrophobic–hydrophilic balance of copolymers greatly affects their transfection properties. The top-performing polymer, II-70 %, showed improved transfection efficiency and significantly lower cytotoxicity on COS-7 cells when compared with commercial reagents polyethyleneimine (PEI 25K) and Lipofectamine 2000. These results indicate that cationic polymer vesicles with tunable hydrophobicity are promising materials for gene delivery.
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COLLOID AND POLYMER SCIENCE
·
2013
·Vol. 292
·期 4
·895-903
·
IF 2.161
Kang Wanli,Ji Yanfeng,Xu Bin,Hu Leilei,Meng Lingwei,Fan Haiming,Bai Baojun
The host cyclodextrin polymer-P(AM/A-β-CD/NaA) is prepared by redox free-radical copolymerization. Additionally, the multi-sticker amphiphilic polymer-P(AM/BHAM/NaA) as a guest polymer is synthesized using micellar polymerization. The copolymer structures are characterized by 1 H NMR. Subsequently, all the polymers and inclusion complexes are evaluated in terms of apparent viscosity, optical absorption spectra and rheological property. The results indicate that the inclusion association between the cyclodextrin group (CD) and multi-sticker hydrophobic monomer (BHAM) is in accordance with ternary interaction (CD/BHAM = 2:1). Because of the inclusion association between the host and guest polymers, the solution of inclusion complex has much higher viscoelasticity even under the low amphiphilic polymer concentration. When the molar ratio of CD to BHAM is 1:1, the critical aggregation concentration (CAC) of the inclusion complex solution still remains. Furthermore, above the CAC, two types of associations, inclusion association and inter-molecular hydrophobic association, can occur in the complex solution and these interactions were also verified by fluorescence spectroscopy and atomic force microscopy (AFM). In this paper, the inclusion rule of cyclodextrin polymer with the multi-sticker amphiphilic polymer is discussed, and the rule of the enhanced solution viscosity is further explored.
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ACS Applied Materials & Interfaces
·
2015
·
IF 6.723
Xiaosong Guo,Yulu Chen,Ming Su,Dong Li,Guicun Li,Chengdong Li,Yu Tian,Chuncheng Hao,Qingquan Lei
Titanium dioxide and Nb-doped titanium dioxide microspheres with the same size were fabricated by a simple sol–gel method, and the formation mechanism of Nb-doped titanium dioxide microspheres was proposed. Titanium dioxide and Nb-doped titanium dioxide microspheres were adopted as dispersed materials for electrorheological (ER) fluids to investigate the influence of the charge increase introduced by Nb doping on the ER activity. The results showed that Nb doping could effectively enhance the ER performance. Combining with the analysis of dielectric spectroscopy, it was found that the interface polarization of Nb-doped TiO2 ER fluid was larger than that of TiO2 ER fluid, which might be caused by more surface charges in Nb-TiO2 microspheres due to Nb5+ doping and resulting in enhancement of electric field force and strengthening of fibrous structure. In addition, by comparing and analyzing the permittivity curves of Nb-TiO2/LDPE solid composite and Nb-TiO2/silicone-oil fluid composite, it could be concluded that the enhancement of permittivity at low frequency resulted from the increase of the order degree of dispersed particles in ER fluid rather than from the quasi-dc (QDC) behavior. Moreover, the absolute value of slope of permittivity curves (K) at 0.01 Hz could be utilized as the standard for judging the ability to maintain the chainlike structure. The relationships between polarizability of dispersed particles, dielectric spectrum, parameter K, and ER properties were discussed in detail.
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高影响因子
JOURNAL OF PHYSICAL CHEMISTRY B
·
2015
·
IF 3.302
Mei Huang,Shuai He,Wenhong Liu,Yunjin Yao,Shiding Miao
Studies on the configuration of dye molecules are of great importance in revealing origins of the electronic bands as well as understanding their transitions. In this work, we utilized dye molecules named Nile blue A, which are a type of oxazine dyes, to study the molecular configurations when they are transferred from solutions to a solid surface. The Langmuir–Blodgett (LB) technique was employed to construct such an interface where the interaction between the dye molecules and solid supports can be pursued. Hybrid films were prepared via the LB depositions, and the dye molecules were assembled on the elementary clay sheets (laponite, saponite). The configuration of Nb reflected by the molecular orientation, packing density, phase behavior, and variances of the surface tension has been derived. The ex situ spectroscopy characterizations such as UV–vis absorption, fluorescence emission, and excitation spectra were carried out on these LB films to reveal the fact that the adsorbed Nb molecules are mainly assembled in two types of configurations. Adsorbed state I was found to be achieved at high concentrations (1–10 ppm) of clay dispersions and low surface pressure (∼5 mN/m). In this state the anionic oxazine rings of Nb are adsorbed on clay sheets sharing a large lift-off area. This configuration gives allowable fluorescence (λ = 550 nm). Lower clay concentration (<1 ppm) and high surface pressure (10–30 mN/m) yield the adsorbed state II in which the oxazine chromophores were arranged in a side-by-side style, and the dye molecules stand perpendicularly to the clay sheets. This conformation exhibits no photoluminescence.
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