中空介孔氧化硅纳米颗粒的制备及应用进展

集空腔与介孔结构于一体的中空介孔氧化硅纳米材料(HMSNs)因其高比表面积、可调孔径、低密度和高渗透等特性,而在诸多领域展现了极大的潜在应用前景。该文对中空-介孔氧化硅纳米颗粒的主要制备方法及其优缺点进行了概述,着重阐述了硬核模板法、液体界面组装法和界面重组与转换法的研究进展;同时,介绍了中空介孔氧化硅纳米颗粒在生物医药、催化和光学领域方面的应用。最后,对其制备和应用目前存在的挑战以及后续突破方向进行了分析和展望。     

中空介孔氧化硅纳米颗粒的制备及应用进展

集空腔与介孔结构于一体的中空介孔氧化硅纳米颗粒因其高比表面积、可调孔径、低密度和高渗透等特性,而在诸多领域展现了极大的潜在应用前景。本文对中空-介孔氧化硅纳米颗粒的主要制备方法及其优缺点进行了概述,着重阐述了硬核模板法、液体界面组装法和界面重组与转换法;同时介绍了中空介孔氧化硅纳米颗粒在生物医药、催化和光学领域的应用情况。最后,对其制备和应用存在的挑战和研究方向进行了分析和展望。     

介孔氧化硅负载贵金属催化剂研究进展

有序介孔氧化硅材料具有独特的结构和性质,如高的比表面积、大的孔容、均一的孔径分布、丰富的结构和形貌等,在多相催化领域受到广泛的关注和研究。本文回顾了近年来介孔氧化硅在负载贵金属催化剂方面的研究现状,介绍了直接浸渍法、官能团修饰法、原子层沉积法、一锅合成法等不同的负载方法,归纳比较了各种方法之间的优缺点。同时也指出了介孔有序SiO2材料在催化负载方面存在的一些局限,并对其发展前景做了展望,认为降低介孔氧化硅的成本、提高载体的水热稳定性、开发新结构和性能的介孔氧化硅以及探索新的催化剂负载工艺,将是未来介孔氧化硅在多相催化领域应用研究的重要方向。     

Impact of inhibitor loaded mesoporous silica nanoparticles on waterborne coating performance in various corrosive environments

This article is a contribution to the development of the smart, self-healing solutions in the context of corrosion protection of metallic materials based on nanotechnology. Mesoporous silica nanoparticles were successfully synthesized and loaded with two different corrosion inhibitors, 1-hydroxybenzotriazole and 8-hydroxyquinoline. Loaded particles were embedded in different concentrations in waterborne epoxy coating, and as such applied to low carbon steel substrates. A continuous immersion test in 3.5% NaCl solution, humidity chamber exposure, and salt spray exposure were performed. Successful synthesis of silica nanoparticles has been demonstrated using scanning electron microscopy and energy-dispersive X-ray spectroscopy characterization techniques. Fourier transform infrared spectroscopy was used to confirm the loading of inhibitors, while the quantity of loaded inhibitors was determined by thermogravimetric method. Anticorrosive performance of intact composite coatings was determined using electrochemical impedance spectroscopy and open-circuit potential measurements. Adhesive properties were determined using the pull-off test (ISO 4624). Significant improvement in corrosion protection performance has been demonstrated for coatings containing inhibitor-loaded nanoparticles.     

银原位改性HMS材料的结构及抗菌性能

采用溶胶凝胶法,以银氨离子为银源,原位合成了含Ag六方介孔硅（Ag-HMS）无机抗菌材料,探讨了其抗菌性能,并利用XRD、FT-IR、TG-DTA、UV-Vis、ESEM、EDS及N₂的吸附/脱附等方法对材料进行了表征。结果表明,材料保持了良好的介孔结构和热稳定性,具有良好的紫外线吸收性能,银物种以骨架态和非骨架态形式存在并且分散均匀;相对于HMS,Ag-HMS材料脱模时的热化学过程、孔体积、介孔有序度、比表面积及粒子形貌均发生了显著改变。在抑菌实验中,Ag-HMS对枯草杆菌(B.subtilis)、大肠杆菌(E.coil)、芽孢杆菌(G.bacillus)及金黄色葡萄球菌(S.aureus)均显示出良好的抗菌性能,其中对枯草杆菌和大肠杆菌尤为显著,当Ag-HMS用量为1.00 mg·L^-1,12 h后即可将两者彻底杀灭。     

H2-induced copper and silver nanoparticle precipitation inside sol-gel silica optical fiber preforms

ABSTRACT: Ionic copper- or silver-doped dense silica rods have been prepared by sintering sol-gel porous silica xerogels doped with ionic precursors. The precipitation of Cu or Ag nanoparticles was achieved by heat treatment under hydrogen followed by annealing under air atmosphere. The surface plasmon resonance bands of copper and silver nanoparticles have been clearly observed in the absorption spectra. The spectral positions of these bands were found to depend slightly on the particle size, which could be tuned by varying the annealing conditions. Hence, transmission electron microscopy showed the formation of spherical copper nanoparticles with diameters in the range of 3.3 to 5.6 nm. On the other hand, in the case of silver, both spherical nanoparticles with diameters in the range of 3 to 6 nm and nano-rods were obtained.     

纳米氧化锌/二氧化硅杂化体的制备及其对天然橡胶复合材料性能的影响

采用3-氰基丙基三乙氧基硅烷（CTOS）对二氧化硅（SiO₂）进行了氰基化改性,并采用热溶剂法将纳米ZnO沉积于氰基官能化SiO₂（SiO₂-CN）表面,制备出纳米氧化锌/二氧化硅杂化体（ZnO@SiO₂）,并使用X射线衍射仪、傅里叶变换红外光谱仪、扫描电镜等对杂化结构进行表征。将ZnO@SiO₂作为填料添加入天然橡胶中制备复合材料（NR/ZnO@SiO₂）,然后对ZnO@SiO₂与橡胶的界面关系进行了分析,并研究了ZnO@SiO₂对橡胶复合材料的硫化特性、力学性能的影响。结果表明,纳米ZnO成功沉积在SiO₂-CN表面,并且NR/ZnO@SiO₂复合材料表现出优异的机械性能和硫化特性。与天然橡胶相比,仅添加5份杂化体的NR/ZnO@SiO₂复合材料的拉伸强度、100%定伸及300%定伸强度分别增加了150.2%、86.2%和65.5%,并且正硫化时间缩短了38.5%。     

Silica foams with ultra-large specific surface area structured by hollow mesoporous silica spheres

Ceramic foams with multi-scale pores and large specific surface area have received extensive attention due to their unique structure and superior properties. Considering that there are still challenges to synthesize porous ceramics with large specific surface area, a novel ceramic foam material with ultra-large specific surface area has been prepared using hollow silica mesoporous spheres (HMSSs) as building block in this work. These building blocks were made weakly hydrophobic in order to produce HMSS particle stabilized foams. The foams exhibit a uniform primary macropore structure, which is composed of a three dimensional HMSS-assembled network, via HMSS-stabilized foams. The influence of sintering temperature on the microstructure and properties of HMSS foams is investigated. The HMSS foams exhibit highest specific surface area of 1733 m²/g, attributed to the radial mesopores in HMSS shell, when sintered at between 500°C and 800°C. This specific surface area is much higher than that of existing ceramic materials. The uniform pore structure and ultra-large specific surface area make it a promising lightweight material in potential application fields, including catalyst, adsorption, fire-resistant thermal insulation, and load and control release system.     

氧化锌纳米棒改性涤纶绸缎的超疏水与抑菌性能

采用温和的湿化学法在涤纶绸缎的表面生长一层取向排列的氧化锌纳米棒阵列。利用X射线衍射仪和场发射扫描电子显微镜对产物进行结构分析和表面形貌观察,通过液滴形状分析系统及纸片法抑菌实验对其湿润性和抑菌性进行表征和测量。结果表明:经氧化锌纳米棒表面改性的涤纶绸缎与水的接触角达到148°,展现出良好的超疏水性能;同时,经取向氧化锌纳米棒阵列改性后的涤纶绸缎对致病性大肠杆菌、金黄色葡萄球菌等细菌表现出了良好的抑制作用。该产品在服装和包装等行业有着诱人的应用前景。     

Preparation and characterization of novel PVA bionanocomposites based on 4H-pyran loaded on silica nanoparticles: Morphological aspects and antibacterial activity

This research consisted of the following steps: (a) synthesis of new organic modifier, (b) preparation of novel generation of silane coupling agent, (c) fabrication of organic modified silica NPs, and (d) preparation of polyvinyl alcohol-based NCs. The obtained materials were characterized by different spectroscopic methods. Also, the microbial activities of surface-modified silica bionanoparticles on Gram-positive and Gram-negative bacteria were investigated.     

An ordered mesoporous hydroxyapatite: Preparation,loading, and sustained releasing to ciprofloxacin

A kind of new mesoporous hydroxyapatite (noted as mesoHA) with about 2.4 nm average porous diameter was successfully prepared by casting Ca²⁺ and H₂PO₄⁻ ions on the inner channel surface of Si-MCM-41 and dissolving the Si-MCM-41 in alkali soluble, and the porous material was used as a pH-responsive platform to adsorb and release ciprofloxacin molecules. A maximum mass of 0.51 mg of ciprofloxacin (noted as Cip) was loaded on 1.00 mg of the host, and the release rate of the drug was found increasing with the acidic increase of the external solution environment (based on the stability of mesoHA) that simulated basic composition to human plasma. About 88.5% of Cip was released from the platform when environmental pH value was about 4.8, which provides a new method on utilizing antibiotics drugs efficiently, for the host mesoHA is friendly to human body.     

Stepwise surface modification of mesoporous silica and its use in poly(urethane-urea) composite films

The compatibility between polymer matrix and filler is a vital issue in the fabrication of composites with desirable properties. To enhance the interfacial adhesion between matrix and filler, various surface modification treatments are applied. The objective of this study was to increase the affinity of silica and poly(urethane-urea)s (PUUs), thereby improving the mechanical properties of the resulting composites. Stepwise surface modification of mesoporous silica with amine-containing dendrimers was done. Various techniques were used to confirm the surface-modified structure during the stepwise reaction. Additionally, the N₂ adsorption–desorption method indicated a gradual reduction in surface area, pore diameter and pore volume of the particles, which warrants the gradual propagation of the dendrimers on the surface and also inside the pores. A type IV isotherm was obtained in this analysis. Two types of pre-synthesized PUUs were chosen for composite preparation containing the surface-modified silica with 0.5, 1, 2.5 and 5 wt% concentrations. Due to the high affinity of the dendrimers containing amine moieties on the particles with polyurethane, a proper dispersion of particles in the matrix was achieved based on scanning electron micrographs. Tensile measurements showed an increased Young's modulus and strength of polyurethane films as a result of addition of the particles. However, no significant improvement in the tensile performance of the composites was seen above 2.5 wt% particle loading due to some particle aggregations. © 2021 Society of Industrial Chemistry.     

Highly antibacterial and toughened polystyrene composites with silver nanoparticles modified tetrapod‐like zinc oxide whiskers

In this work, high‐performance multifunctional composites were obtained by melt blending silver deposited tetrapod‐like zinc oxide whiskers (Ag‐ZnOw) with polystyrene (PS). The chemical, spectroscopic, antibacterial, mechanical, and morphological properties of the PS/Ag‐ZnOw composites were carefully investigated and discussed. The obtained PS/Ag‐ZnOw composites characterized remarkable antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Moreover, it is found that impact strength of the composite increase with increasing nanofiller concentration (up to 0.25 wt %). Morphological characterization of the impact fractured surface of composites revealed that toughening was achieved through uniform filler distribution in the polymer matrix, and anchoring effect was imparted by the tetrapod‐like shape of ZnO whiskers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40900.     

Immobilization of glucose oxidase and platinum on mesoporous silica nanoparticles for the fabrication of glucose biosensor

In this study, amino group modified mesoporous silica nanoparticles (MSN) were prepared and used to immobilize both platinum nanoparticles (PtNP) and glucose oxidase (GOx). The prepared MSN–PtNP demonstrated high stability and reactivity for catalyzing H₂O₂ electro-reduction, mainly due to the large amount of PtNP immobilized, the high surface area of these catalysts and the unique nanostructures formed through the synthetic route. Working at −0.2 V, the linear range in response to H₂O₂ by the prepared MSN–PtNP can be 5 × 10⁻⁷ to 6 × 10⁻² mol L⁻¹. After immobilizing GOx onto MSN–PtNP, the resulting MSN–PtNP–GOx was capable of interference-free determination of glucose with the linear range as wide as 1 × 10⁻⁶ to 2.6 × 10⁻² mol L⁻¹. Furthermore, the fabricated glucose biosensor can offer significant advantages compared with its conventional counterparts, typically like the high sensitivity, good reproducibility and stability, and rapid response ability as well. The fabricated glucose biosensor demonstrated its potential in clinical applications, so as to enable the determination of glucose in real serum samples.     

Effect of silica on the ZnS nanoparticles for stable and sustainable antibacterial application

Silica-capped Zinc Sulfide (ZnS) nanoparticles were synthesized for the use as stable and long-term antibacterial agents because silica is a very important component in food packaging applications for moisture absorption in tune with its property of biocompatibility and water solubility. The variation in morphological and optical properties of core-shell nanostructures was studied by changing the concentration of silica in a core-shell combination. The structural and morphological properties of silica-capped ZnS have been observed by powder X-ray diffraction (PXRD) and transmission electron microscopic (TEM) studies, respectively. Uncapped ZnS nanoparticles with particle size of 2-4 nm in a highly agglomerated state have been observed from TEM, which shows that they can be used only for short-term antibacterial action despite its excellent zone of inhibition (antibiotic sensitivity). However, ZnS/SiO₂ core-shell nanostructures are highly monodisperse in nature and the particle size increases up to 5-8 nm with increase in silica concentration. Fourier-transform infrared spectroscopy (FTIR) analysis confirms the formation of silica capping on the ZnS surface. The inhibition of defect-related emission by silica capping in energy-resolved photoluminescence studies also shows the formation of very stable ZnS nanoparticles. To study the antibacterial properties of the pure and silica-capped ZnS nanostructure the agar-well diffusion method was employed against both gram-positive and gram-negative bacteria. The obtained results indicate that pure ZnS shows excellent antibacterial action but it can last only for few days.     

In vitro efficacy and toxicology evaluation of silver nanoparticle‐loaded gelatin hydrogel pads as antibacterial wound dressings

The silver nanoparticle (nAg)‐loaded gelatin hydrogel pads were prepared from 10 wt % gelatin aqueous solution containing silver nitrate (AgNO₃) at 0.75, 1.0, 1.5, 2.0, or 2.5 wt % by solvent‐casting technique. These AgNO₃‐containing gelatin solutions, that had been aged for 15, 12, 8, 8, and 8 h, respectively, showed noticeable amounts of the as‐formed nAgs, the size of which increased with an increase in the AgNO₃ concentration (i.e., from 7.7 to 10.8 nm, on average). The hydrogels were crosslinked with a glutaraldehyde aqueous solution (50 wt %, at 1 μL mL^?1). At 24 h of submersion in phosphate buffer saline (PBS) or simulated body fluid buffer (SBF) solution, about 40.5–56.4% or 44.4–79.6% of the as‐loaded amounts of silver was released. Based on the colony count method, these nAg‐loaded hydrogels were effective against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, with at least about 99.7% of bacterial growth inhibition. Unless they had been treated with a sodium metabisulfite aqueous solution, these hydrogels were proven, based on the indirect cytotoxicity evaluation, to be toxic to human's normal skin fibroblasts. Lastly, only the hydrogels that contained AgNO₃ at 0.75 and 1.0 wt % were not detrimental to the skin cells that had been cultured directly on them. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Molecular Level Characterisation of the Surface of Carbohydrate-Functionalised Mesoporous silica Nanoparticles (MSN) as a Potential Targeted Drug Delivery System via High Resolution Magic Angle Spinning (HR-MAS) NMR Spectroscopy

Atomistic level characterisation of external surface species of mesoporous silica nanoparticles (MSN) poses a significant analytical challenge due to the inherently low content of grafted ligands. This study proposes the use of HR-MAS NMR spectroscopy for a molecular level characterisation of the external surface of carbohydrate-functionalised nanoparticles. MSN differing in size (32 nm, 106 nm, 220 nm) were synthesised using the sol-gel method. The synthesised materials displayed narrow particle size distribution (based on DLS and TEM results) and a hexagonal arrangement of the pores with a diameter of ca. 3 nm as investigated with PXRD and N₂ physisorption. The surface of the obtained nanoparticles was functionalised with galactose and lactose using reductive amination as confirmed by FTIR and NMR techniques. The functionalisation of the particles surface did not alter the pore architecture, structure or morphology of the materials as confirmed with TEM imaging. HR-MAS NMR spectroscopy was used for the first time to investigate the structure of the functionalised MSN suspended in D₂O. Furthermore, lactose was successfully attached to the silica without breaking the glycosidic bond. The results demonstrate that HR-MAS NMR can provide detailed structural information on the organic functionalities attached at the external surface of MSN within short experimental times.     

Amino functionalized mesoporous silica microspheres with perpendicularly aligned mesopore channels for electrochemical detection of trace 2,4,6-trinitrotoluene

Core-shell structured mesoporous silica microspheres with a SiO₂ particles core and an ordered perpendicularly aligned mesoporous silica shell to the surface have been prepared. The perpendicular orientation mesoporous silica microspheres (SiO₂@mSiO₂) then were functionalized with 3-aminopropyltriethoxysilane (APTS) to graft amino functional groups (SiO₂@mSiO₂@NH₂). The SiO₂@mSiO₂@NH₂ was used to modify glassy carbon electrodes (GCE) as sensing material. Square-wave voltammetry was used to detect the reduction peak of 2,4,6-trinitrotoluene (TNT) in a three-electrode system. The results demonstrate that the SiO₂@mSiO₂@NH₂/GCE can greatly improve the response to TNT due to the large active surface area and high preconcentration efficiency via specific interaction between electron-rich amino groups and electron-deficient aromatic rings. The first reduction peak current of TNT at the SiO₂@mSiO₂@NH₂/GCE is ca. 4.6 times larger than that at the un-functionalized SiO₂@mSiO₂/GCE. A limit of determination of 0.5 nM and a sensitivity of 0.011 μA nM⁻¹ was obtained. Excellent wide linear range (2.0-50.0 nM) and good repeatability (relative standard deviation of 2.4%) were obtained for TNT. Moreover, the SiO₂@mSiO₂@NH₂/GCE shows a higher electrochemical response to TNT than to 1,3,5-trinitrobenzene (TNB) and 2,4-dinitrotoluene (DNT), and the first reduction peak current of TNT at the SiO₂@mSiO₂@NH₂/GCE is 2.9 and 4.8 times larger than that of DNT and TNB, respectively, which shows the as-prepared SiO₂@mSiO₂@NH₂/GCE has a much higher sensitivity to TNT than other kinds of nitroaromatics.