JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2013
·
IF 2.004
Qian Zhang,Xiuhong Wang,Xilian Wei,Jie Liu
The detailed micellization behavior of 3-alkyloxy-2-hydroxypropyl trimethylammonium chloride (RnHTACl, n = 12, 14, 16) in aqueous solution was studied by electric conductivity, steady-state fluorescence, and isothermal titration microcalorimetry (ITC) methods. The critical micelle concentration (CMC) and degree of counterion dissociation (α0) were estimated from conductivity curves in the temperature range of 293.15 K to 323.15 K. Then the thermodynamic parameters of micellization (ΔGm0, ΔHm0, and ΔSm0) were calculated by applying a mass-action model equation. On the basis of the ITC results, the CMCs and thermodynamic parameters were also estimated at 293.15 K, which were basically consistent with the results from the conductivity method. According to the Turro–Yekta method, the micelle aggregation number (Nagg) of RnHTACl was determined through static luminescence quenching, and found that the decreased temperature, the elongation of the alkyl chain length or the increased concentration of RnHTACl could lead to an increase of the Nagg.
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POLYMER DEGRADATION AND STABILITY
·
2015
·
IF 3.163
Hongli Wu,Binbin Wen,Hua Zhou,Jiadong Zhou,Zuolong Yu,Liyan Cui,Ting Huang,Fei Cao
Polyethylene 2, 5-furandicarboxylate-lactic acid copolyesters (PEFL) were synthesized from bis (hydroxyethyl)-2, 5-furandicarboxylate and oligomer of l -lactic acid, through two-stage condensation . The polyesters were characterized using FTIR, 1 H NMR, GPC , and WXRD. The weight-average molecular weight (M w ) of the polyesters ranged from 68240 to 130433. The glass transition temperature (T g ) of the copolyesters increased gradually with increasing content of 2, 5-furandicarboxylate. In phosphate buffer solution (PBS, pH = 7.4) and in soil, the degradability of the polyesters was evaluated for 55 d. More weight loss was obtained with a higher ratio of lactate polymers in soil than those with a lower ratio in PBS. After 55 d, the weight loss of PEFL20/80 reached 65% and 24% in soil and PBS, respectively. However, the mole fraction of lactyl and furanic units that was calculated by 1 H NMR data did not change. Comparing the scanning electron microscopy images, we found many micro-cracks on the copolyester surfaces. Meanwhile, M w and T g also decreased prominently during degradation.
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ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
Mingshu Xiao,Dazhang Yang,Yuhua Yan,Yanping Tian,Mao Zhou,Meifeng Hao,Rui Cheng,Yuqing Miao
The Co 3 (VO 4 ) 2 multilayer nanoplates [Co 3 (VO 4 ) 2 -MNs] and Co 3 (VO 4 ) 2 ultrafine particle-comprised nanospheres [Co 3 (VO 4 ) 2 -UPNs] were prepared for the oxygen evolution reaction (OER). They are synthesized by a simple hydrothermal reaction using ethylenediaminetetraacetic acid and polyvinyl pyrrolidone as dispertants and pretectants. With the help of multi-walled carbon nanotubes (MWCNTs), the Co 3 (VO 4 ) 2 -MNs and Co 3 (VO 4 ) 2 -UPNs were immobilized respectivtly onto the surface of glassy carbon electrodes (GCEs). By comparison, the GCE–Co 3 (VO 4 ) 2 -MN/MWCNT exhibits higher performance of OER electrocatalysis and better stablity than the GCE–Co 3 (VO 4 ) 2 -UPN/MWCNT in the alkali electrolyte of 1 M KOH due to its higher surface roughness. The high surface free energy of Co 3 (VO 4 ) 2 -MNs is helpful for their immobilization on elelctrode surface, leading a better stability. The work shows that the noble metal-free electrocatalysts can lower the energy barrier and improve the energy efficiency for electrochemical water splitting to generate hydrogen.
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Materials
·
2015
·Vol. 8
·期 3
·1009-1026
·
IF 2.651
Juan Wang,Dongsong Li,Tianyi Li,Jianxun Ding,Jianguo Liu,Baosheng Li,Xuesi Chen
Surface coating is the simplest surface modification. However, bioactive molecules can not spread well on the commonly used polylactone-type skeletons; thus, the surface coatings of biomolecules are typically unstable due to the weak interaction between the polymer and the bioactive molecules. In this study, a special type of poly(lactide-co-glycolide) (PLGA)-based scaffold with a loosened skeleton was fabricated by phase separation, which allowed gelatin molecules to more readily diffuse throughout the structure. In this application, gelatin modified both the internal substrate and external surface. After cross-linking with glutaraldehyde, the surface layer gelatin was tightly bound to the diffused gelatin, thereby preventing the surface layer gelatin coating from falling off within 14 days. After gelatin modification, PLGA scaffold demonstrated enhanced hydrophilicity and improved mechanical properties (i.e., increased compression strength and elastic modulus) in dry and wet states. Furthermore, a sustained release profile of recombinant human bone morphogenetic protein-2 (rhBMP-2) was achieved in the coated scaffold. The coated scaffold also supported thein vitroattachment, proliferation, and osteogenesis of rabbit bone mesenchymal stem cells (BMSCs), indicating the bioactivity of rhBMP-2. These results collectively demonstrate that the cross-linked-gelatin-coated porous PLGA scaffold incorporating bioactive molecules is a promising candidate for bone tissue regeneration.Keywords:biomaterials;bone tissue engineering;gelatin;surface coating;recombinant human bone morphogenic protein-2
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Analytical Methods
·
2014
·Vol. 6
·期 6
·1736-1742
·
IF 1.938
Shiquan Xiong,Junjie Cheng,Lulu He,Min Wang,Xin Zhang,Zhengyan Wu
A β-cyclodextrin–graphene (β-CD–G) hybrid composite modified glassy carbon electrode for the first time was used for electrochemically detecting di(2-ethylhexyl)phthalate (DEHP), based on the inclusion of DEHP into β-CD. The electrode was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. At the composites electrode, the impedance value increased linearly with the increasing DEHP concentration in the range of 2 μM to 18 μM, the limit of detection was 0.12 μM (3σ method), with a correlation coefficient of 0.998. The electrode showed good selectivity, reproducibility and stability. Obviously, the collected amounts of DEHP by β-CD–G could be detected through this electrochemical method. Furthermore, this simple and low-cost sensing platform can in principle be extended to the detection of other phthalate esters which can form host–guest complexes with cyclodextrin.
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Journal of Materials Chemistry A
·
2013
·Vol. 1
·期 37
·11438-11442
·
IF 0
Songjie Fan,Fuxing Sun,Jijiang Xie,Jin Guo,Laiming Zhang,Chunrui Wang,Qikun Pan,Guangshan Zhu
Cu(bipy)2(SiF6) is a highly porous metal–organic framework (MOF) and represents a prototypal “pillared sheet” platform offering opportunities to control the pore sizes. Its structural features, low cost and facile synthesis make it a great candidate to fabricate membranes for gas separation. The key to obtaining thin, continuous Cu(bipy)2(SiF6) membranes is to control the Cu(bipy)2(SiF6) crystal growth and enhance the binding between membrane and substrate. Here we explored a new route by direct synthesis and successfully obtained a continuous thin Cu(bipy)2(SiF6) membrane on a macroporous glass-frit disk with high robustness. It is speculated that the SiF62− used to construct the Cu(bipy)2(SiF6) membrane came from the fluorinated substrate. The Cu(bipy)2(SiF6) membrane shows the separation factors of H2–CO2, H2–CH4 and H2–N2 are 8.0, 7.5, and 6.8 respectively at 293 K and 1 bar with H2 permeance of 2.7 × 10−7 mol m−2 s−1 Pa−1 as well as high thermal stability. We expect to explore more membranes of Cu(bipy)2(SiF6) analogues with tuneable pore sizes using this route and to obtain membranes with higher gas separation performance.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2013
·
IF 2.206
Jinming Peng,Yanlei Su,Wenjuan Chen,Xueting Zhao,Zhongyi Jiang,Yanan Dong,Yan Zhang,Jiazhen Liu,Xiaochen Fan
In this study, a solvent-free approach to antifouling membranes is tentatively presented. The membrane bulk matrix is formed through bulk polymerization of liquid monomer 2-hydroxyethyl methacrylate (HEMA) in the absence of an organic solvent. The membrane pores are formed via removal of silica particles generated from the sol–gel process of tetraethyl orthosilicate. The membranes have a homogeneous structure and acquire water flux around 1020 L m–2 h–1 at 0.1 MPa. The rates of rejection of the yeast and oil droplet for all the polyHEMA membranes are above 97.0 and 99.0%, respectively. The polyHEMA membranes exhibit strong hydrophilic and excellent fouling resistance properties as a result of hydrophilic HEMA. The flux recovery ratio is as high as 91.0% using protein as a foulant. After the fluorine-containing additive dodecafluoroheptyl methacrylate (DFHM) had been blended in a casting solution, the poly(HEMA/DFHM) membranes possess an amphiphilic surface and exhibit excellent fouling resistance as well as fouling release properties. The flux recovery ratio is >90%, and the total flux decline ratio is as low as 11.7% using an oil/water emulsion as the foulant.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2015
·
IF 2.353
Renping Cao,Dedong Peng,Haidong Xu,Shenhua Jiang,Ting Fu,Wenjie Luo,Zhiyang Luo
A series of Sr 3 (VO 4 ) 2 :Sm 3+ ,P 5+ ,Na + phosphors are synthesized by using solid-state reaction method in air. The strongest emission band peaking at ∼600 nm is assigned to the 4 G 5/2 → 6 H 7/2 transition of Sm 3+ ion, and the strong excitation peak at ∼402 nm due to 6 H 5/2 → 4 F 7/2 transition indicates that these phosphors can be excited by near ultraviolet light emitting diode chip. Energy transfer (ET) between VO 4 3− group and Sm 3+ ion can be observed. Sr 3 (VO 4 ) 2 :Sm 3+ phosphor with excitation 320 nm exhibits a systematically varied hues from green to yellow by changing Sm 3+ ion concentration from 0 to 6 mol%. The luminous mechanism of Sr 3 (VO 4 ) 2 :Sm 3+ phosphor is explained by using the energy level diagrams of VO 4 3− group and Sm 3+ ion. The luminescence properties of Sr 3 (VO 4 ) 2 :Sm 3+ phosphor can be improved and tuned by codoping the P 5+ and Na + ions due to ET and charge compensation. Lifetimes of Sr 2.925 Sm 0.05 (VO 4 ) 2 , Sr 2.925 Sm 0.05 (V 0.9 P 0.1 O 4 ) 2 , and Sr 2.9 Na 0.05 Sm 0.05 (V 0.9 P 0.1 O 4 ) 2 phosphors are 1.208, 1.219, and 0.796 ms, respectively. The experiment results are helpful to adjust the luminescence properties of Sm 3+ -doped other phosphors.
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高影响因子
Materials Science & Engineering C-Materials for Biological Applications
·
2015
·
IF 3.088
Jun Xiang,Jianguo Sun,Jiaxu Hong,Wentao Wang,Anji Wei,Qihua Le,Jianjiang Xu
Corneal disease is a common cause of blindness, and keratoplasty is considered as an effective treatment method. However, there is a severe shortage of donor corneas worldwide. This paper presents a novel T-style design of a keratoprosthesis and its preparation methods, in which a mechanically and structurally effective artificial cornea is made based on a poly(2-hydroxyethyl methacrylate) hydrogel. The porous skirt was modified with hyaluronic acid and cationized gelatin, and the bottom of the optical column was coated with poly(ethylene glycol). The physical properties of the T-style Kpro were analyzed using ultraviolet and visible spectrophotometry and electron scanning microscopy. The surface chemical properties were characterized using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The surface modification in the spongy skirt promoted cell adhesion and produced a firm bond between the corneal tissue and the implant device, while the surface modification in the optic column resisted cell adhesion and prevented retroprosthetic membrane formation. Through improved surgical techniques, the novel T-style keratoprosthesis provides enough mechanical stability to facilitate long-term biointegration with the host environment. In vivo implantation experiments showed that the T-style keratoprosthesis is a promising cornea alternative for patients with severe limbal stem cell deficiency and corneal opacity.
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高影响因子
Journal of Physical Chemistry C
·
2015
·
IF 4.772
Di Bao,Peng Gao,Yanbo Wang,Han Zhou,Yujin Chen,Guorui Chen,Piaoping Yang,Xitian Zhang
In this paper, Cd(OH)2 1D three-side nanobelt architectures have been fabricated through a facile two-phase reaction system. Considering their electropositive character proven by zeta potential measurement, the as-obtained Cd(OH)2 nanomaterials have been applied to capture negatively charged DNA. On the basis of the above results, the Cd(OH)2 nanomaterials have been employed for trapping negatively charged double-stranded DNA molecules (salmon sperm DNA). Assisted by the detailed observation of their DNA interaction results as well as through UV–vis spectroscopy, infrared imaging automatic target recognition (IRATR) and inductive coupled plasma atomic emission spectrometer (ICP-AES) measurements, it has been clearly shown that this 1D nanoarchitecture can effectively trap and release DNA molecules without use of any other organic reagents. In addition, a miniaturized electrochemical DNA-releasing device based on the Cd(OH)2 1D three-side nanobelt architectures has been fabricated. Using this device, it is possible to recycle the Cd(OH)2 nanostructures. In addition, the Cd(OH)2 nanomaterials maintain their nanostructures, and no Cd2+ ions were released in repeated DNA separation and transfer processes, which demonstrate their practicality for DNA trapping.
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MACROMOLECULES
·
2017
·
IF 5.835
Dongdong Zhou,Shaoyong Huang,Jingru Sun,Xinchao Bian,Gao Li,Xuesi Chen
The crystallization behaviors and microstructures of poly(l-2-hydroxyl-3-methylbutanoic acid)/poly(l-lactide) blends [P(L-2H3MB)/PLLA] were investigated by OM, DSC, SAXS, in situ temperature-dependent WAXD, and in situ synchrotron WAXS. The blends exhibited a homogeneous state at 250 °C. In the cooling process, P(L-2H3MB), with higher melting temperature, crystallized first at 166.7 °C and drove the formation of the phase separation and microstructure. And the amorphous P(L-2H3MB) and PLLA were excluded into the interlamellar and interfibrillar regions of the former P(L-2H3MB) crystallites. For P(L-2H3MB)/PLLA (5/5), the amorphous P(L-2H3MB) in the interfibrillar regions continued to form crystallites sequentially at 134.6 °C, which clearly confirmed the fractional crystallization of P(L-2H3MB). In our knowledge, this unique fractional crystallization has not been reported yet, of the component in miscible blend, which crystallized first under little confinement. This work provided a new viewpoint and understanding of the relationship between fractional crystallization and microstructures in crystalline/crystalline blends.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2015
·
IF 2.037
Fang Zhang,Yaocun Tang,Long Wang,Li Xu,Guoji Liu
The solubility behavior of 2-naphthaldehyde in six pure solvents (methanol, ethanol, isopropanol, n-butyl alcohol, n-heptane, and n-hexane) and binary solvent mixtures of methanol + ethanol with various concentrations were experimentally studied by the equilibrium method at temperatures ranging from (283.15 to 313.15) K and (283.15 to 308.15) K, respectively, under an atmosphere pressure of 0.1 MPa. The solubilities of 2-naphthaldehyde in the pure solvents accord with the following order: ethanol > isopropanol > n-butyl alcohol > methanol > n-heptane > n-hexane. In the mixed solvents, the solubility of 2-naphthaldehyde increases with decreasing mass fraction of methanol. All of the solubility data were correlated with the van’t Hoff equation, the modified Apelblat equation, and the λh equation. The correlation results with the modified Apelblat equation showed better agreement with the experimental values than those with the other two models. Furthermore, the thermodynamic properties of the dissolution process of 2-naphthaldehyde were also calculated and discussed.
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