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1.
The formation of hierarchical porous protein scaffolds from oil‐in‐water (o/w) high internal phase emulsions (HIPEs) stabilized by bovine serum albumin (BSA) protein nanoparticles (Pickering HIPE) is reported. The route consists of three principal steps. First, a stable o/w HIPE stabilized by BSA protein nanoparticles is formulated. Next, crosslinking the dispersed protein nanoparticles gives rise to a gel in the continuous water phase to freeze the emulsion's microstructure. Finally, removal of the oil components and water directly leads to a three dimensional, bimodal meso‐macroporous protein scaffold, which is suitable for a wide range of biomedical applications.  相似文献   

2.
《化学:亚洲杂志》2017,12(4):470-475
Significant progress has been made on the synthesis and application of mesoporous γ‐alumina. To date, little attention has been paid to the synthesis of microporous crystalline alumina. Here, fabrication of microporous crystalline γ‐alumina using a microporous covalent triazine framework (CTF‐1) as a template is described. Microporous crystalline γ‐alumina with a micro‐meso binary pore system was replicated by infiltration of aluminum nitrate into the micropores of the CTF‐1 template through a NH3/water‐vapor‐induced internal hydrolysis method, followed by thermal treatment, and subsequent removal of the CTF‐1 template with a 30 % H2O2 aqueous solution. The obtained crystalline γ‐alumina material exhibits a large surface area (349 m2 g−1) with micropore distribution centered at about 1.27 nm. Ru supported on microporous γ‐Al2O3 can be employed as catalyst for hydrolytic dehydrogenation of ammonia borane, and it exhibits high catalytic activity and good durability. This finding provides a new benchmark for preparing well‐defined crystalline microporous alumina materials by a template method, which can be applied in a wide range of fields.  相似文献   

3.
Hierarchical ZSM‐5 zeolites with micro‐, meso‐ and macroporosity were prepared from diatomite zeolitization through a vapor‐phase transport process on solid surfaces. The aromatization performance of the catalysts was investigated on a fixed bed reactor by using FCC gasoline as feedstock. The crystal phase, morphology, pore structures, acidity and coke depositions of the hierarchical ZSM‐5 zeolites were characterized by means of X‐ray diffraction (XRD), scanning electron microscope (SEM), N2 adsorption/desorption, Fourier transform infrared (FT‐IR) and thermogravimetry‐mass spectrogram (TG‐MS), respectively. The results show that the prepared hierarchical ZSM‐5 zeolite possesses excellent porosity and high crystallinity, displaying an improved aromatization performance and carbon deposition resistance due to its meso‐ and macroporous structures.  相似文献   

4.
A novel synthesis method for ordered mesoporous carbons is presented. The inverse replication of a silica template was achieved using the carbonization of sucrose within mesoporous KIT‐6. Instead of liquid acid etching, as in classical nanocasting, a novel dry chlorine etching procedure for template removal is presented for the first time. The resultant ordered mesostructured carbon material outperforms carbons obtained by conventional hard templating with respect to high specific micro‐ and mesopore volumes (0.6 and 1.6 cm3 g?1, respectively), due to the presence of a hierarchical pore system. A high specific surface area of 1671 m2 g?1 was achieved, rendering this synthesis route a highly convenient method to produce ordered mesoporous carbons.  相似文献   

5.
Macroscopic monoliths are highly desirable in many fields of application. Herein, well organized organic–inorganic cryogel composite with a three‐dimensional hierarchical meso‐ and macroporous structure are presented, which were produced by in situ copolymerization of mesoporous multifunctional silica (size: 1–20 μm; pore: 2–20 nm mostly) and monomers (hydroxyethyl methacrylate and diallyldimethylammonium chloride) in water below the freezing point. This copolymerization method effectively adjusted the macropores of the basic cryogel, and the nanosilica was more homogeneously dispersed in the basic cryogel. The specific surface area of the cryogel composite was increased 17 times versus than that of the basic cryogel. The abundant meso‐ and macroporous pores on the cryogel composite provided sufficient reactive sites favorable for the efficient mass transport of target compounds. When the cryogel composite, as solid phase extraction adsorbent, was coupled with high‐performance liquid chromatography, an analytical tool, the nucleosides were quantified with good selectivity, lower detection limits (0.9–1.3 ng/mL) and satisfactory recoveries of greater than 80% from spiked human serum.  相似文献   

6.
Two types of templates, an active metal salt and silica nanoparticles, are used concurrently to achieve the facile synthesis of hierarchical meso/microporous FeCo‐Nx‐carbon nanosheets (meso/micro‐FeCo‐Nx‐CN) with highly dispersed metal sites. The resulting meso/micro‐FeCo‐Nx‐CN shows high and reversible oxygen electrocatalytic performances for both ORR and OER, thus having potential for applications in rechargeable Zn–air battery. Our approach creates a new pathway to fabricate 2D meso/microporous structured carbon architectures for bifunctional oxygen electrodes in rechargeable Zn–air battery as well as opens avenues to the scale‐up production of rationally designed heteroatom‐doped catalytic materials for a broad range of applications.  相似文献   

7.
Micro/nanoscale magnesium silicate hollow spheres were synthesized by using silica colloidal spheres as a chemical template in one pot. The hollow spherical structure, consisting of well‐separated nanoscale units, was microscale as a whole and could be easily handled in solution. The as‐synthesized magnesium silicate hollow spheres with large specific surface area showed availability for the removal of organic and heavy‐metal ions efficiently from waste water. Importantly, the micro/nanoscale magnesium silicate hollow spheres that had adsorbed organic pollutants could be regenerated by calcination and used repeatedly in pollutant removal. Magnesium silicate hollow spheres synthesized by a scaled‐up chemical template method may have potential applications in removing cationic dyes and heavy‐metal ions from waste water.  相似文献   

8.
A novel meso–macroporous bioglass has been synthesized based on a sol–gel technique. This method used mushroom stalk as macroporous template and EO20PO70EO20 as the mesoporous template. The final sample has copied the macroporous structure of the plant template, precisely. Ibuprofen was used as the model drug, and the drug loading and release test indicated the loading amount of the sample could reach 33.59 wt% and the releasing amount closed 75 wt% after 48 h. The excellent biomineralization and bioactive are also confirmed in vitro tests. It takes only 4 h to induce the formation of hydroxyapatite. Notably, the biocompatibility assessment confirmed that the obtained materials presented good biocompatibility and the enhanced adherence of HeLa cells. The exquisite mesoporous structure of the sample would be propitious to storage and transport guest molecule, making the hierarchical porous materials have more distinctive performance and application on bone tissue regeneration and drug delivery, etc.  相似文献   

9.
采用双模板法,向正硅酸甲酯的水解体系中同时引入聚乙二醇和三嵌段共聚物,成功制备出具有双连续大孔、同时孔壁中分布着有序介孔的复合孔结构硅胶独石材料. 产物的比表面积高达880 m2/g, 大孔孔径为0.2~5 μm, 介孔高度集中地分布在 5 nm. 结合物理吸附、扫描电镜、粉末X射线衍射和透射电镜等表征手段,发现合成条件如原料组成、反应温度和pH值等对反应体系中凝胶化转变和相分离发生的相对速度有重要影响,进而影响产物复合孔结构的生成. 此外,通过对合成条件的优化,一方面增强了无机骨架的强度,另一方面降低了湿凝胶干燥过程中的毛细管压力降,有效缓和了凝胶结构在干燥过程中的开裂和变形,使复合孔结构硅胶独石在厘米尺度内具有良好的整体性能.  相似文献   

10.
In this work we propose a new crosslinking agent and the method to use it for the synthesis of acrylate based hydrogels. The use of this diacrylate of glycerol, synthesized in our laboratory, allows the generation of materials with well defined micro‐structures in the dry state, unique meso‐ and macro‐structures during swelling, and enhanced mechanical properties and swelling capacity in water. These properties depend on the crosslinking agent concentration, as well as synthesis thermal history. Poly(acrylamide‐co‐acrylic acid) hydrogels are commonly crosslinked with N, N′‐methylenebisacrylamide or N‐isopropylacrylamide. Here we obtain and use a new crosslinking agent, obtained from the reaction between glycerol and acrylic acid to produce a Diacrylate of glycerol (DAG). Two synthesis methods at equivalent molar ratio of acrylamide/acrylic acid (AM/AA) were analyzed. The mechanical properties, the swelling capacity, and the morphology at microscale of these hydrogels showed a well defined transition at a critical concentration of crosslinking agent. DAG induces the generation of hydrogels with hierarchichal structure. The micro‐structure surface morphology was investigated by scanning electron microscopy, the meso‐structure by polarized light microscopy and the macro‐structure by CCD imaging. The hydrogels with hierarchical structures showed improved mechanical properties when compared with structureless hydrogels. Control of the microstructure allows the generation of materials for different applications, i.e. templates or smart materials that interact with electromagnetic radiation. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2667–2679, 2008  相似文献   

11.
Replacing platinum as an oxygen reduction catalyst is an important scientific and technological challenge. Herein we report a simple synthesis of a complex carbon with very good oxygen reduction reaction (ORR) activity at pH 13. Pyrolysis of magnesium nitrilotriacetate yields a carbon with hierarchical micro/meso/macro porosity, resulting from in situ templating by spontaneously forming MgO nanoparticles and from etching by pyrolysis gases. The mesopores are lined with highly graphitic shells. The high ORR activity is attributed to a good balance between high specific surface area and mass transport through the hierarchical porosity, and to improved electronic conductivity through the graphitic shells. This novel carbon has a high surface area (1320 m2g?1), and high nitrogen content for a single precursor synthesis (~6 %). Importantly, its synthesis is both cheap and easily scalable.  相似文献   

12.
Specially synthesized extra‐large crystallites of zeolite LTA with intentionally added mesoporosity are used for an in‐depth study of guest diffusion in hierarchical nanoporous materials by the pulsed field gradient NMR technique. Using propane as a guest molecule, intracrystalline mass transfer is demonstrated to be adequately described by a single effective diffusivity resulting from the weighted average of the diffusivities in the two (micro‐ and meso‐) pore spaces. Gas‐kinetic order‐of‐magnitude estimates of the diffusivities are in satisfactory agreement with the experimental data and are thus shown to provide a straightforward means for predicting and quantifying the benefit of hierarchically structured nanoporous materials in comparison with their purely microporous equivalent.  相似文献   

13.
A negatively charged poly(para ‐phenyleneethynylene) (PPE) forms electrostatic complexes with four positively charged antimicrobial peptides (AMP). The AMPs partially quench the fluorescence of the PPE and discriminate fourteen different bacteria in water and in human urine by pattern‐based fluorescence recognition; the AMP‐PPE complexes bind differentially to the components of bacterial surfaces. The bacterial species and strains form clusters according to staining properties (Gram‐positive and Gram‐negative) or genetic similarity (genus, species, and strain). The identification and data treatment is performed by pattern evaluation with linear discriminant analysis (LDA) of the collected fluorescence intensity data.  相似文献   

14.
An efficient and environment friendly surface‐protected etching method by using mesoporous silica as a template and alkaline polyelectrolyte as both the protecting and etching agent was developed to prepare a SiO2 nanotube with a porous shell. The polyelectrolytes attached to the template not only create a localized alkaline environment, but also effectively protect the silica surface, whereas the mesopore channels accelerate the diffusion of etchant throughout the template, all of which facilitate the formation of hollow structures in a fully controllable way. By tuning the etching power and protecting ability of the polyelectrolyte, the rigidity and porosity of products can be precisely manipulated. It is inspiring that various alkaline polyelectrolytes including polypeptide and dextran derivative can be used for the etching process, so that the porous and hollow nanostructures are born with positively charged and biocompatible surface as well as abundant amino groups for further coupling, which make them potential capsules for drug delivery and probes for imaging and detection. The protective etching process can also be extended to the preparation of yolk‐shell super structures with functional cores, or porous nanoparticle assemblies with their individual characteristics maintained.  相似文献   

15.
In spite of recent advances in the synthesis of hollow micro/nanostructures, the fabrication of three‐dimensional electrodes on the basis of these structures remains a major challenge. Herein, we develop an electrochemical sacrificial‐template strategy to fabricate hollow Co3O4 microtube arrays with hierarchical porosity. The resultant unique structures and integrated electrode configurations impart enhanced mass transfer and electron mobility, ensuring high activity and stability in catalyzing oxygen and hydrogen evolution reactions. Impressively, the apparent performance can rival that of state‐of‐the‐art noble‐metal and transition‐metal electrocatalysts. Furthermore, this bifunctional electrode can be used for highly efficient overall water splitting, even competing with the integrated performance of Pt/C and IrO2/C.  相似文献   

16.
The development in the synthesis and self‐assembly of patchy nanoparticles has resulted in the creation of complex hierarchical structures. Co‐assembly of polymeric nanoparticles and protein molecules combines the advantages of polymeric materials and biomolecules, and will produce new functional materials. Co‐assembly of positively charged patchy micelles and negatively charged bovine serum albumin (BSA) molecules is investigated. The patchy micelles, which were synthesized using block copolymer brushes as templates, leads to co‐assembly with protein molecules into vesicular structures. The average size of the assembled structures can be controlled by the molar ratio of BSA to patchy micelles. The assembled structures are dissociated in the presence of trypsin. The protein–polymer hybrid vesicles could find potential applications in medicine.  相似文献   

17.
沸石分子筛是许多工业过程中不可缺少的催化剂。其中,Beta沸石因其具有三维大微孔结构而成为生产广泛并且具有重要工业意义的沸石材料之一。与传统微孔Beta沸石相比,多级孔Beta沸石具有更小的空间位阻,更高的传质效率等诸多优点,从而能减少其在作为催化剂时积碳的形成,从而延长催化剂的使用寿命,提高催化剂利用效率。本文以Beta沸石为代表,从“自下而上”(直接合成)和“自上而下”(后期修饰)两种策略详细地介绍了多级孔沸石合成的研究进展,对硬模板剂法、软模板剂法、无介孔模板剂法、脱铝法和脱硅法进行了全面的介绍,并简要介绍了多级孔Beta沸石的特点,最后总结了各种合成方法的优点及存在的问题并对其未来发展前景进行了展望。  相似文献   

18.
《中国化学》2018,36(1):51-54
Antireflection surfaces and coatings have attracted considerable interests because they can maximize light transmittance of the substrates. In this work, zeolite antireflective (ZAR) coatings are prepared via layer‐by‐layer (LBL) assembly of MFI ‐type zeolite silicalite‐1 and polyelectrolyte. A micro‐ and macroporous hierarchical structure was obtained which contributes to the antireflective property of the zeolite coatings. The light transmittance of the coating on quartz can achieve as high as 99.3% at 650 nm. Furthermore, a superhydrophobic ZAR coating can be obtained by chemical modification with 1H,1H,2H,2H–perfluorooctyl‐triethoxysilane. This work demonstrates that zeolites are excellent candidates as high transparent superhydrophobic coatings.  相似文献   

19.
The tendency of bacteria to assemble at oil–water interfaces can be utilized to create microbial recognition sites on the surface of polymer beads. In this work, two different groups of bacteria were first treated with acryloyl‐functionalized chitosan and then used to stabilize an oil‐in‐water emulsion composed of cross‐linking monomers that were dispersed in aqueous buffer. Polymerization of the oil phase followed by removal of the bacterial template resulted in well‐defined polymer beads bearing bacterial imprints. Chemical passivation of chitosan and cell displacement assays indicate that the bacterial recognition on the polymer beads was dependent on the nature of the pre‐polymer and the target bacteria. The functional materials for microbial recognition show great potential for constructing cell–cell communication networks, biosensors, and new platforms for testing antibiotic drugs.  相似文献   

20.
In this paper, one kind of well-ordered hierarchical mesoporous–macroporous bioactive glasses (MMBG) scaffolds with large pore size of 60–120 μm and mesoporous phase in inner-wall has synthesized successfully. This method used stem core of corn as macroporous template and P123 as mesoporous template. The final samples have replicated the structure of the macroporous plant templates precisely. Since the aperture and pore structure of different plants are variable, it provides a possible way for the synthesis of materials with various aperture holes and pore structure. The organizational structure of final sample is benefit to transport and storage guest molecule, making these hierarchical porous materials have more superior performance and application in the field of macromolecules separation, bone tissue regeneration, and drug delivery, etc. The in vitro tests indicated hierarchical MMBG scaffolds have well capacity for inducing the HA growth. They have the potential to satisfy the demands of bone tissue engineering regeneration.  相似文献   

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