RSC Advances
·
2016
·Vol. 6
·期 35
·29279-29287
·
IF 3.289
Mei Liu,Wanquan Jiang,Qian Chen,Sheng Wang,Ya Mao,Xinglong Gong,Ken Cham-Fai Leung,Jie Tian,Huijuan Wang,Shouhu Xuan
A facile one-step method was developed to synthesize core–shell structured SiO2@polydopamine (PDA) nanospheres. During the synthesis, a PDA shell was simultaneously coated on the SiO2 nanospheres to form the core–shell nanostructure. The PDA shell thickness was tunable by varying the concentration of the starting dopamine precursor. After dispersing the core–shell nanospheres into poly(ethylene glycol) 200 (PEG200), a SiO2@PDA based shear thickening fluid (STF) was obtained. In comparison to pristine SiO2, the SiO2@PDA based STF presented better ST effects and its maximum viscosity could reach as high as 194.6 Pa s. A possible enhancement mechanism was proposed in order to investigate the structural dependence of the ST effect. This high performance SiO2@PDA based STF could be widely applied in body armor and other safe-guarding areas.
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MONATSHEFTE FUR CHEMIE
·
2016
·Vol. 147
·期 9
·1605-1614
·
IF 1.131
Zhang Dawei,Chen Xiaodong,Guo Xue,Zhang Yumin,Hou Yaya,Zhao Tianqi,Gu Qiang
Abstract An efficient synthesis of 1,4-dihydropyridines was developed. 1,4-Dihydropyridines were synthesized starting from various 3-substituted isoxazolyl-5-carbaldehydes, ethyl acetoacetate, and ammonium acetate under microwave irradiation and solvent-free conditions (86–96 %), and were characterized by HRMS, FT-IR, 1 H NMR, and 13 C NMR spectroscopy. Solid support SiO 2 was found to possess favorable catalysis and dispersancy for the condensation reaction. The merits of the method included the environmental friendly reaction conditions, simple operation, extensive substrates, good yields and reuse of the SiO 2 . Moreover, the crystal structure of compound diethyl 4-[3-(2-methoxyphenyl)isoxazol-5-yl]-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate in orthorhombic Pbca space group was presented. Graphical abstract
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RSC Advances
·
2016
·Vol. 6
·期 66
·61109-61118
·
IF 3.289
Baowen Sun,Chunsheng Wang,Shuhua Han,Yongfeng Hu,Lijuan Zhang
A silver nanocube (Ag NC) nanoparticle-enhanced fluorescent nanocomposite was developed. The designed nanocomposite contained an Ag NC core of 50 nm in size as enhancer, the 10 nm silica interlayer, and outer shell-periodic mesoporous organosilicas (PMOs) which incorporated the bis(rhodamine Schiff-base derivative) siloxane groups. Little fluorescence emission of nanocomposites was observed due to the existence of spirolactam in the rhodamine derivative, however, upon the addition of Cu2+, the fluorescence emission intensity increased dramatically, which resulted from ring-opening of the spirolactam in the rhodamine moieties. We showed the effect of using an Ag NC core on the fluorescence emission intensity of the novel system. The emission intensity was approximately 3-fold higher for Ag-nanocube@SiO2@PMOs than the control sample prepared by etching the silver core away with iodide. Moreover, the metal-enhanced fluorescence (MEF) mechanism in this system was investigated through measuring the fluorescence lifetime. In addition, the designed core–shell Ag-nanocube@SiO2@PMOs nanocomposite could act as a sensitive and selective sensor to detect the Cu2+, and we have been expecting that the detection limit would be reduced by reaping benefits from the plasmon resonance of Ag NC core in this nanocomposite system.
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NANOTECHNOLOGY
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2017
·Vol. 28
·期 41
·415301
·
IF 3.44
Sanyuan Hu,Heping Li,Zhen Su,Youwei Yan
This paper describes a near-field electrospinning technique combined with heat treatment process used to directly align parallel metal oxide and metal nitride fibers on silicon dioxide substrate. The effects of near-field electrospinning parameters (including collector-to-needle distance, applied voltage and the moving speed of the collector) on the morphology of the resulted fibers have been studied. Metallic salt-contained precursor fibers are individually aligned via near-field electrospinning of metallic salts and polymeric solution mixtures. After applying calcination process to these well aligned precursor fibers, patterning by metal oxide and metal nitride fibers such as ZnO, Ga2O3, TiO2, GaN and TiN is successfully obtained. The optical microscope images and the scanning electron microscopy show the presence of fiber patterns, whose crystalline structure is characterized by x-ray diffraction and Raman spectroscopy measurement. The results demonstrate the potential of this approach for assembling ceramic fibers into parallel arrays with controllable orientation and position.
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PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2016
·
IF 3.15
Tongtong Han,Caifeng Li,Xiangyu Guo,Hongliang Huang,Dahuan Liu,Chongli Zhong
A series of SiO 2 @aluminum-MOF(MIL-68) composites with different SiO 2 loadings have been synthesized by a simple and mild compositing strategy for high-efficiency removal of aniline. As evidenced from SEM and TEM images as well as the particle size distribution , the incorporation of SiO 2 can improve the dispersity of MIL-68(Al) in composites, and result in the smaller particle size than that of pristine MIL-68(Al). Besides, the adsorption of aniline over SiO 2 , MIL-68(Al), the physical mixture of these two materials, and SiO 2 @MIL-68(Al) composites was investigated comparatively, demonstrating a relatively high adsorption capacity (531.9 mg g −1 ) of 7% SiO 2 @MIL-68(Al) towards aniline. Combining the ultrafast adsorption dynamics (reaching equilibrium within 40 s) and great reusability, 7% SiO 2 @MIL-68(Al) shows excellent adsorption performance. This indicates that the SiO 2 @MIL-68(Al) composites possess great potential applications as a kind of fascinating adsorbent in water pollution protection.
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RSC Advances
·
2016
·Vol. 6
·期 84
·81310-81317
·
IF 3.289
Yue Liu,Lu Li,Shiwei Liu,Congxia Xie,Shitao Yu
(3-Aminopropyl)-triethoxysilane (APTS) and (3-mercaptopropyl)-trimethoxysilane (MPTS) grafted SiO2-coated iron oxide (Fe3O4@SiO2) magnetic supports were prepared. Various noble metal nanoparticles such as Ru, Pt, Rh and Pd were directly grown on the surfaces of the magnetic supports with ultrasmall and nearly monodisperse sizes, especially the APTS grafted Fe3O4@SiO2 (Fe3O4@SiO2/APTS) nanospheres. The Fe3O4@SiO2/APTS/Ru catalyst demonstrated a high catalytic activity towards the hydrogenation of α-pinene to form cis-pinane. The conversion of α-pinene was 99.1% and the selectivity for cis-pinane reached 97.6% at 120 °C after 4 h. The Fe3O4@SiO2/APTS/Ru catalyst was easily separated from the reaction mixture when applying an external magnetic field, and the separated Fe3O4@SiO2/APTS/Ru had good reusability. After being reused eight times, the α-pinene conversion and the cis-pinane selectivity also can reach 97.8% and 96.9%, respectively.
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TRIBOLOGY INTERNATIONAL
·
2016
·
IF 2.259
Yuanliang Zhao,Xiaowen Qi,Yu Dong,Jian Ma,Qinglong Zhang,Laizhou Song,Yulin Yang,Qingxiang Yang
Polyimide (PI)/nano-SiO 2 composites were successfully fabricated via a novel in-situ polymerization. Microstructure, thermal properties, mechanical performance and tribological behaviors of these composites were investigated. The results indicate that nano-SiO 2 dispersed homogeneously. Compared with pure PI, thermal stability and heat resistance are higher about 10 °C with the addition of 5 wt% nano-SiO 2 . Compressive strength and modulus of composite with 5 wt% nano-SiO 2 increase by 42.6 and 45.2%, respectively. The coefficient of friction (COF) of composite with 5 wt% nano-SiO 2 decrease by 6.8% owing to the thick and uniform transfer films. Excess nano-SiO 2 could adversely affect the COF of PI/nano-SiO 2 composite. Additionally, wear resistance deteriorates obviously since transfer film exfoliates easily and nano-SiO 2 aggregates on the surface of transfer films.
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MICROCHIMICA ACTA
·
2017
·Vol. 184
·期 7
·2241-2248
·
IF 4.58
Zhang Yufeng,Zhou Zhiping,Zheng Jiahong,Li Hongji,Cui Jiuyun,Liu Siwei,Yan Yongsheng,Li Chunxiang
The authors describe a fluorescence based assay for determination of the macrolid antibiotic erythromycin (ERY). It is based in the use of fluorescent gold nanoclusters (AuNCs) coated first with silica (to obtain AuNC@SiO 2 ) and then with a molecularly imprinted polymer (MIP). The MIP was synthesized from 3-aminopropyltriethoxysilane as the functional monomer, ERY as the template, and tetraethoxysilane as the cross-linker via a sol-gel process that leads to surface imprinting. By using this method, the strong fluorescence of AuNCs was maintained in the resultant MIPs. After optimization of the experimental conditions, the signal (measured at excitation/emission wavelengths of 396/585 nm) decreases linearly with increasing concentration of ERY in the 0.1 to 11.9 μM ERY concentration range. The limit of detection is 12 nM, and the imprinting factor is 4.0. The method was successfuly applied to the determination of ERY in spiked human urine and saliva.
Schematic of the preparation of a core-shell sensor material with the silica coated by fluorescent gold nanoclusters as core and a molecularly imprinted polymer. It can be used to selectively detect residual erythromycin in biological samples.
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Journal of Materials Chemistry C
·
2016
·Vol. 4
·期 41
·9841-9847
·
IF 5.066
Yuqi Zhang,Lidan Mu,Ru Zhou,Pei Li,Jiaqi Liu,Loujun Gao,Liping Heng,Lei Jiang
We demonstrate a quickly responsive, highly sensitive, excellently selective and conveniently recyclable fluorescent film sensor for the detection of formaldehyde (FA) vapor, which is based on Fluoral-p infiltrated SiO2 inverse opal photonic crystals (IOPCs). The as-prepared sensor combined the properties of the IOPC’s interconnected macroporous structure, high surface area, and slow photon effect which can amplify the fluorescence, and the formation of a fluorescent product generated from selective reaction between Fluoral-p and FA. Upon exposure to FA vapor for 20 s, the resulting fluorescence can be clearly observed and the intensity can be magnified remarkably. The fluorescence enhancement for FA detection on the optimized sensor can be up to 76.3-fold compared with that for the control sample. The sensor achieved a detection limit of 0.008 mg m−3 and had good selectivity for FA. Additionally, the sensor could be easily recycled by washing with ethanol, followed by infiltration by Fluoral-p again. Therefore, the designed Fluoral-p infiltrated IOPC can be utilized as a highly effective fluorescent sensor for detecting gaseous FA, which provides a promising strategy for improving response rate and detection sensitivity, and has enormous potential for the detection of other gases by choosing suitable IOPCs and functional reaction molecules.
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Catalysis Science & Technology
·
2016
·Vol. 7
·期 1
·168-180
·
IF 5.287
Xiaoxiong Huang,Yong Men,Jinguo Wang,Wei An,Yuanqiang Wang
A series of magnesia–silica binary composite catalysts with different molar ratios were prepared using various preparation methods and evaluated for the one-step production of 1,3-butadiene (BD) from bio-ethanol. The MgO–SiO2 catalyst prepared by wet-kneading is distinguished from the samples prepared by other methods by its superior activity. An exceptionally high productivity of butadiene with the high ethanol conversion of 95% and BD selectivity of 77% was obtained over wet-kneaded hierarchical flower-like MgO nanostructures with the catalytic material made up of SiO2 spheres (with a MgO : SiO2 molar ratio of 65 : 35 at 450 °C and an WHSV of 4.1 h−1), which translates into an unprecedented BD yield of 0.025 mol gcat−1 h−1. The as-prepared catalysts were characterized by XRD, FESEM, BET, FT-IR, UV/vis, CO2-TPD and NH3-TPD. The Mg precursor used and the preparation method are found to influence the extent of MgO and SiO2 interactions during preparation, as estimated by various techniques, which, in turn, was found to correlate with the catalytic performance. A subtle balance of surface acidity/basicity was found to be necessary to achieve a high butadiene yield which can be obtained by variation of MgO : SiO2 ratios in wet-kneaded samples. In view of the difference in catalytic activity and the physicochemical properties of the MgO–SiO2 composite catalysts, the Si–O–Mg chemical bond formed by the strong MgO and SiO2 interaction is suggested to be essential for the balanced surface acid/base sites in relation to the strong interaction between MgO and SiO2 and the consequent high catalytic performance.
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JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2017
·Vol. 82
·期 2
·424-431
·
IF 1.575
Zhang Jing,Liu Mao,Liu Zhijie,Yang Tao,He Qiulai,Yang Kai,Wang Hongyu
Abstract This paper presents the synthesis of a novel core–shell covalently functionalized Fe 3 O 4 coated SiO 2 decorated graphene oxides (Fe 3 O 4 @SiO 2 –GO) adsorbent. The prepared Fe 3 O 4 @SiO 2 –GO was characterized by fourier transform infrared spectrum, X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), and magnetic measurements. And the adsorption properties of the Fe 3 O 4 @SiO 2 –GO toward malachite green were systematically investigated. Various factors possibly affecting the adsorption behavior (initial concentration, contact time, and adsorbent dosage) were also studied in detail. The adsorption capacity (q m ) of Fe 3 O 4 @SiO 2 –GO for malachite green was found to be 265.87 mg/g with best fit to Langmuir isotherm ( R
2 = 0.968), and the adsorption mechanism follows the pseudo-second-order model ( R
2 = 0.981). The results indicate that the Fe 3 O 4 @SiO 2 –GO adsorbent, which is easily separated via an external magnetic field, is a potential low-cost effective material for malachite green removal from contaminated water. Graphical Abstract
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CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Xiaolin Liu,Yongxin Tao,Huihui Mao,Yong Kong,Jian Shen,Linhong Deng,Linsong Yang
Near-infrared (NIR) light has great potential in biomedical applications due to its advantages of deep penetration depth and low photodamage to biological tissues. In this paper, we constructed a novel core-shell structured drug nanocarrier, Fe 3 O 4 @Au@SiO 2 , for the controlled delivery of etoposide (VP16), a chemotherapeutic drug for cancer patients. The novel core-shell structured drug delivery platform is composed of a mesoporous silica shell and a magnetic Fe 3 O 4 core using Au nanoparticles (AuNPs) as the interlayer, which is characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, N 2 adsorption/desorption isotherms and the magnetic measurements with vibrating-sample magnetometer (VSM). The synergistic effects of AuNPs, mesoporous silica and Fe 3 O 4 make the core-shell structured nanocomposites an excellent candidate for targeted and NIR light irradiation-controlled drug delivery. For the proposed nanocarrier of VP16, the mesopores in silica can enhance the encapsulation capacity of the nanocarrier and the AuNPs can effectively convert the NIR light into heat to speed up the drug deliver; meanwhile, the incorporation of Fe 3 O 4 with high magnetization to the drug delivery platform realize drug targeting under an applied external magnetic field.
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