Effect of silica nanoparticles/poly(vinylidene fluoride-hexafluoropropylene) coated layers on the performance of polypropylene separator for lithium-ion batteries

In an effort to reduce thermal shrinkage and improve electrochemical performance of porous polypropylene （PP） separators for lithium-ion batteries, a new composite separator is developed by introducing ceramic coated layers on both sides of PP separator through a dip-coating process. The coated layers are comprised of heat-resistant and hydrophilic silica nanoparticles and polyvinylidene fluoride-hexafluoropropylene （PVDF-HFP） binders. Highly porous honeycomb structure is formed and the thickness of the layer is only about 700 nm. In comparison to the pristine PP separator, the composite separator shows significant reduction in thermal shrinkage and improvement in liquid electrolyte uptake and ionic conduction, which play an important role in improving cell performance such as discharge capacity, C-rate capability, cycle performance and coulombic efficiency.

Radio-frequency-heating capability of silica-coated manganese ferrite nanoparticles

MnFe204 nanoparticles （NPs） with various sizes and tight size-distribution were synthesized by a chemical solution- phase method. The as-synthesized NPs were coated with a silica shell of 4 nm-5 nm in thickness, enabling the water- solubility and biocompatibility of the NPs. The MnFe204 NPs with a size of less than 18 nm exhibit superparamagnetic behavior with high saturated magnetization. The capacity of the heat production was enhanced by increasing particle sizes and radio frequency （RF） field strengths. MnFe204/SiO2 NPs with 18-nm magnetic cores showed the highest heat- generation ability under an RF field. These MnFe204/SiO2 NPs have great potentiality to cancer treatments, controlled drug releases, and remote controls of single cell functions.

Photodegradation and Aggregation Prevention of Natural Melanin Nanoparticles by Silica Coating Method

Melanin, the main photoreceptor in living organics, is largely abundant in pigmented hair tissues. Its promising properties have been widely studied in order to fully explore the corresponding applications. However, the photodegradating and aggregating natures of melanin, to some extent, restrict the development of this eco-friendly biomaterial. This study is conducted to overcome both disadvantages by a mature method that coating the original melanin nanoparticles with silica as shells. The results revealed that the aggregation of the melanin/silica nanoparticles (MSNP) was decreased obviously by a 5 h coating and appeared a uniformly mono-dispersed solution. The MSNP that coated for 20 h provided an efficient protection on the photodegradation of the melanin with a 50% maintenance of the melanin content compared with 16% of original melanin and 2% of MSNP-5 h.

Hydrophilic Silica/Copolymer Nanoparticles and Protein-Resistance Coatings

Hydrophilic silica/copolymer nanoparticles of SiO2-g-P(PEGMA)-b-P(PEG) are prepared by silica surface-initiating atom transfer radical polymerization (SI-ATRP) of poly (ethylene glycol) methyl ether methacrylate (PEGMA) and poly(ethylene glycol) methacrylate (PEG), by using Three molar ratios of SiO2-Br/PEGMA/PEG as 1/42.46/19.44, 1/42.46/38.88 and 1/42.46/77.76. Their temperature sensitive behaviour, pH response and surface properties as protein-resistance coatings are characterized. 220 nm core-shell nanoparticles as P(PEGMA)-b-P(PEG) shell grafted on SiO2 core are formed in water solution, which gained LCST at 60。C - 77。C and good dispersion in water when pH > 5.0. The water-casted films by SiO2-g-P(PEGMA)-b-P(PEG) obtain a little rough surface (Ra = 26.8 - 29.7 nm). While, the introduction of P(PEG) segments could slight increase the protein-repelling adsorption of SiO2-g-P(PEGMA)-b-P(PEG) films (△f = ?6.96 Hz ~ ?7.25 Hz) compared with SiO2-g-P(PEGMA) films (△f = ?9.5 Hz). Therefore, SiO2-g-P(PEGMA)-b-P(PEG) could be used as protein-resistance coatings.

Bioinspired Hollow Mesoporous Silica Nanoparticles Coating on Titanium Alloy with Hierarchical Structure for Modulating Cellular Functions

3D-printed Porous Titanium Alloy Implants(pTi),owing to their biologically inertness and relatively smooth surface morphology,adversely affect the biological functions of surrounding cells.To address the challenges,constructing a bioinspired interface that mimics the hierarchical structure of bone tissue can enhance the cellular functions of cells.In this context,Hollow Mesoporous Silica Nanoparticles(HMSNs),renowned for their unique physicochemical properties and superior biocompatibility,offer a promising direction for this research.In this research,the initially synthesized HMSNs were used to construct a“hollow-mesoporous-macroporous”hierarchical bioinspired coating on the pTi surface through the Layer-by-Layer technique.Simultaneously,diverse morphologies of coatings were established by adjusting the deposition strategy of PDDA/HMSNs on the pTi surface(pTi-HMSN-2,pTi-HMSN-4,pTi-HMSN-6).A range of techniques were employed to investigate the physicochemical properties and regulation of cellular biological functions of the diverse HMSN coating strategies.Notably,the pTi-HMSN-4 and pTi-HMSN-6 groups exhibited the uniform coatings,leading to a substantial enhancement in surface roughness and hydrophilicity.Meantime,the coating constructed strategy of pTi-HMSN-4 possessed commendable stability.Based on the aforementioned findings,both pTi-HMSN-4 and pTi-HMSN-6 facilitated the adhesion,spreading,and pseudopodia extension of BMSCs,which led to a notable upsurge in the expression levels of vinculin protein in BMSCs.Comprehensive analysis indicates that the coating,when PDDA/HMSNs are deposited four times,possesses favorable overall performance.The research will provide a solid theoretical basis for the translation of HMSN bioinspired coatings for orthopedic implants.

Preparation and luminescence properties of monodisperse silica/aminosilane-coated Y_2O_3:Yb,Ho upconversion nanoparticles

Monodisperse silica/aminosilane-coated Y 2 O 3:Yb,Ho nanoparticles are prepared via homogenous precipitation combined with a polyvinylpyrrolidone-assisted ammoniation method.The factors that contribute to the success of the coating are examined,and the procedure is optimized.Compared with uncoated nanoparticles,coated nanoparticles exhibit an increased ratio of green to red emission intensity,which can mainly be attributed to the decreased number of surface defects induced by the surface coating.

Fabrication and ultraviolet-shielding properties of silica-coated titania-doped ceria nanoparticles

A series of well-dispersed titania-doped ceria nanoparticles Ce1–xTixO2 were rapidly prepared by a novel salt-assisted solution combustion process using correspondent metal nitrates as oxidizers and ethyl glycol as fuel, and then coated with amorphous silica by seeded polymerization using tetraethyl orthoslicate （TEOS）. The as-prepared samples were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, Fourier-transform infrared spectroscopy （FTIR）, and ultraviolet-visible light （UV-Vis） diffuse reflectance spectroscopy. The results indicated that compared with the as-prepared pure ceria nanoparticles, the red-shift phenomenon occurred for Ti-doped ceria nanoparticles with Ti incorporation. Meanwhile, the absorption intensity in the UV light region slightly decreased and transmission rate in visible light region was somewhat enhanced. In comparison with the silica-coated CeO2 nanopowders, the silica-coated Ce0.95Ti0.05O2 nanopowders displayed the same absorption intensity in the UV light region, broader UV absorption band and higher transmission rate in visible light region.

Effect of Temperature on Thermal Treatment of Silica Coated Magnetic Nanoparticles

In the quest for developing a catalyst with as many desired characteristics, a facile synthetic route was designed for the preparation of mesoporous silica coated magnetic nanoparticles（MSMNP） employing a colloid mill reactor. The composite particles were characterized by the techniques, such as nitrogen adsorption-desorption isotherms, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction patterns （XRD）, thermo-gravimetric analysis（TGA）, Fourier transform infrared spectroscopy（FTIR） and vibrating sample magnetometer（VSM）, etc. The analysis showed that the resulted MSMNP composites were composed of silica shell layers with open pores connecting channels and NiFe204 with spinel structure, so the thermal treatment temperature did not show significant effect on pore textural properties, and its specific surface areas were in the range of 443-- 474 m2/g, while pore volume of about 0.8 cm3/g with an average pore size of around 9.5 nm. The composites with super paramagnetic nature were encapsulated entirely with amorphous silica layers contributing to optimum porosity and abundant surface hydroxyl groups.

Silica-coating-assisted nitridation of TiO_(2) nanoparticles and their photothermal property

Nanoparticles of refractory compounds represent a class of stable materials showing a great promise to support localized surface plasmon resonances(LSPRs)in both visible and near infrared(NIR)spectral regions.It is still challenging to rationally tune the LSPR band because of the difficulty to control the density of charge carriers in individual refractory nanoparticles and maintain the dispersity of nanoparticles in the processes of synthesis and applications.In this work,controlled chemical transformation of titanium dioxide(TiO_(2))nanoparticles encapsulated with mesoporous silica(SiO_(2))shells to titanium nitride(TiN)via nitridation reaction at elevated temperatures is developed to tune the density of free electrons in the resulting titanium-oxide-nitride(TiO_(x)N_(y))nanoparticles.Such tunability enables a flexibility to support LSPR-based optical absorption in the synthesized TiO_(x)N_(y)@SiO_(2) core-shell nanoparticles across both the visible and NIR regions.The silica shells play a crucial role in preventing the sintering of TiO_(x)N_(y) nanoparticles in the nitridation reaction and maintaining the stability of TiOxNy nanoparticles in applications.The LSPR-based broadband absorption of light in the TiO_(x)N_(y)@SiO_(2) nanoparticles exhibits strong photothermal effect with photo-to-thermal conversion efficiency as high as〜76%.

光伏玻璃用高透明无氟超疏水涂层的制备及其性能研究

在光伏玻璃上制备透明超疏水涂层的方法有多种,但大多数纳米粒子采用氟硅烷改性,不仅对环境不友好,而且对人体有害。在本研究中,提出了一种喷涂不含氟的纳米粒子来制备透明超疏水涂层。经过十八胺(ODA)修饰的SiO_(2)纳米颗粒附着在半固化的粗糙水性聚氨酯(WPU)层上,提供低表面能和粗糙度。采用非氟改性剂六甲基二硅氮烷(HMDS),进一步提高了涂层的疏水性能。实验结果表明,在400~700 nm波长范围内,EW3涂层的平均透过率为90.63%,平均静态水接触角(WCA)为155.8°。在自清洁试验中,EW3涂层表面没有砂石残留。一系列的耐久性测试表明,EW3涂层具有优异的粘接性、耐腐蚀性、抗辐射性以及抗水流冲击能力。这种环保和低成本的制备方法为光伏玻璃和其他领域制备环境友好型透明超疏水涂层提供了新的思路。

Functionalization of silica nanoparticles for nucleic acid delivery

Silica nanoparticles （SiNPs） have been widely engineered for biomedical applications, such as bioimaging and drug delivery, because of their high tunability, which allows them to perform specific functions. In this review, we discuss the functionalization and performance of SiNPs for nucleic acid delivery. Nucleic acids, including plasmid DNA （pDNA） and small interfering RNA （siRNA）, constitute the next generation molecular drugs for the treatment of intractable diseases. However, their low bioavailability requires delivery systems that can circumvent nuclease attack and kidney filtration to ensure efficient access to the target cell cytoplasm or nucleus. First, we discussed the biological significance of nucleic acids and the parameters required for their successful delivery. Next, we reviewed SiNP designing for nucleic acid delivery with respect to nucleic acid loading and release, cellular uptake, endosomal escape, and biocompatibility. In addition, we discussed the co-delivery potential of SiNPs. Finally, we analyzed the current challenges and future directions of SiNPs for advanced nucleic acid delivery.

Preparation and upconversion luminescence of monodisperse Y_2O_2S:Yb/ Ho-silica/aminosilane core-shell nanoparticles

Y2O2S:Yb/Ho-silica/aminosilane core-shell nanoparticles were prepared by a solid-gas method in combination with polyvinylpyr-rolidone assisted one-step ammoniating method. The core was a single Y2O2S:Yb/Ho with 80 nm in diameter and the shell was silica/aminosilane with around 5 nm in thickness. The results of sedimentation experiment indicated that the nanoparticles could be well-dispersed in ethanol and water to form stable colloids. Since the coating weakened lattice vibration energies of the Y2O2S:Yb/Ho...

Bioinspired surface functionalization of biodegradable mesoporous silica nanoparticles for enhanced lubrication and drug release

Osteoarthritis is associated with the significantly increased friction of the joint,which results in progressive and irreversible damage to the articular cartilage.A synergistic therapy integrating lubrication enhancement and drug delivery is recently proposed for the treatment of early-stage osteoarthritis.In the present study,bioinspired by the self-adhesion performance of mussels and super-lubrication property of articular cartilages,a biomimetic self-adhesive dopamine methacrylamide-poly(2-methacryloyloxyethyl phosphorylcholine)(DMA-MPC)copolymer was designed and synthesized via free radical polymerization.The copolymer was successfully modified onto the surface of biodegradable mesoporous silica nanoparticles(bMSNs)by the dip-coating method to prepare the dual-functional nanoparticles(bMSNs@DMA-MPC),which were evaluated using a series of surface characterizations including the transmission electron microscope(TEM),Fourier transform infrared(FTIR)spectrum,thermogravimetric analysis(TGA),X-ray photoelectron spectroscopy(XPS),etc.The tribological test and in vitro drug release test demonstrated that the developed nanoparticles were endowed with improved lubrication performance and achieved the sustained release of an anti-inflammatory drug,i.e.,diclofenac sodium(DS).In addition,the in vitro biodegradation test showed that the nanoparticles were almost completely biodegraded within 10 d.Furthermore,the dual-functional nanoparticles were biocompatible and effectively reduced the expression levels of two inflammation factors such as interleukin-1β(IL-1β)and interleukin-6(IL-6).In summary,the surface functionalized nanoparticles with improved lubrication and local drug release can be applied as a potential intra-articularly injected biolubricant for synergistic treatment of early-stage osteoarthritis.

纳米硅材料对植物生长发育影响的研究进展

随着纳米技术的快速发展,其在植物和农业上的应用已逐渐引起广泛兴趣。作为纳米材料的一种,纳米硅由于独特的结构和物理化学性质被广泛应用。纳米硅材料不断增加的生产和应用是否对环境中的植物及农作物带来影响,是一个值得关注的问题。本文就近年来国内外在纳米硅材料与植物相互作用及其对植物生长发育影响的研究进行了详细综述。首先介绍植物对纳米硅材料的吸附和吸收,分析纳米硅在植物体内的运输方式并描述纳米硅在植物体内的积累和分布情况;随后,详细介绍了纳米硅材料对植物不同生长发育阶段的影响,并分析了该影响产生的生理和分子机理;接着分析了纳米硅材料对植物抗逆性的影响及其原因;阐述了纳米硅作为肥料对植物(尤其是农作物)的应用效果;最后概括了纳米硅材料与植物互作研究中存在的问题、理论深度以及进一步的研究方向,并提出了具体建议,以期为纳米硅材料在农业生产上的安全、高效利用提供参考。

SiO_2纳米粒子对溶胶凝胶涂层性能的影响

在高强钢表面制备了防护性溶胶凝胶涂层,并研究了不同浓度二氧化硅纳米粒子的加入对于涂层形貌、耐蚀性和硬度的影响。采用扫描电子显微镜(SEM)和电子能谱(EDS)观察了涂层的微观结构和成分;采用显微硬度计测试了涂层的硬度;采用电化学方法研究了二氧化硅纳米粒子的浓度对于涂层耐蚀性能的影响;采用傅里叶红外光谱研究涂层的化学结构,进而探讨了二氧化硅纳米粒子对于涂层的强化机理。结果显示涂层加入二氧化硅纳米粒子的最佳浓度为500 mg.L-1,此条件下的涂层表面均匀致密,有较高的硬度并且在3.5%NaCl溶液中体现出较好的耐蚀作用。纳米粒子在溶胶中反应形成活性羟基基团并与硅烷发生反应生成空间网状结构,从而强化涂层。

硅壳纳米颗粒对COS-7细胞的生物效应

从硅壳纳米颗粒对细胞存活率、细胞周期及细胞生长曲线的影响等方面系统地考察了包裹RuBpy染料的硅壳荧光纳米颗粒(FSiNPs)对美洲绿猴肾细胞(COS-7)的生物效应.结果表明,FSiNPs对COS-7细胞的影响是浓度依赖性的,低浓度(<0.2μg/μL)的FSiNPs对细胞的存活率、细胞周期及整个生长过程均无负面影响,但随着与COS-7细胞作用的FSiNPs浓度的增大,FSiNPs对COS-7细胞的毒性也逐渐增大,尤其是对细胞周期及细胞生长曲线的影响更为敏感.同时,利用FSiNPs的荧光信号同步指示作用,考察了COS-7细胞对FSiNPs的吞噬作用,发现FSiNPs通过细胞膜的吞噬作用随机地进入到细胞内,一部分FSiNPs被细胞当成异物外排到细胞培养基中,另一部分则进入到下一代细胞中.随着细胞传代次数的增多和新生胞质的产生,FSiNPs在细胞内的含量逐渐减少,最后消失.在这一过程中,细胞的形态和生长状况依然良好.上述研究结果有望为FSiNPs在细胞生物学的研究和应用提供一定的安全标准,并为开展基于新型纳米颗粒的纳米颗粒器件的研究与应用打下了基础.

纳米二氧化硅在外墙涂料中的改性研究

在传统的建筑用外墙涂料中加入纳米SiO2得到纳米涂料，比较了加入纳米SiO2前、后涂料涂膜的性能。结果表明，涂料中纳米SiO2的最佳用量为0．3～1．0g，在此用量内，所得纳米涂料的稳定性、流平性均有所提高；涂膜的耐洗刷性为原来的2倍，耐碱性从原来的48h无异常增强为7d无异常，耐老化时间从之前的500h延长至1000h。

Ag纳米粒子聚集体的SiO_2包覆及其SERS效应

为实现表面增强拉曼散射(SERS)信号的快速检测分析,报道了一种简单的利用SiO2包覆对巯基苯甲酸(4MBA)修饰的Ag纳米粒子形成核壳结构纳米颗粒SERS标记物的方法。通过调控溶液中硝酸钠的浓度来控制4MBA-Ag的聚集程度,获得不同的"热点"效应,然后利用SiO2包覆实现对聚集体的固定。扫描电镜结果证实此种方法非常有效。该体系中SERS的信号强度依赖于4MBA-Ag的聚集程度。该研究结果有助于实现聚集体SERS标记物在生物成像、检测和传感等方面的应用。

自组装法制备中空二氧化硅纳米粒子减反射薄膜

以正硅酸乙酯（TEOS）为壳层材料,聚丙烯酸（PAA）为核材料,以传统的St？ber水解法为基础制备得到结构规整的中空二氧化硅纳米粒子,并采用自组装法制备单层减反射薄膜和宽波段双层减反射薄膜。主要研究中空二氧化硅纳米粒子的结构调控方法;自组装次数和中空二氧化硅纳米粒子分散液的pH值对减反射薄膜透光率的影响规律,以及具有渐变折射率的双层减反射薄膜的制备。研究结果表明：通过调节PAA和TEOS的用量可精确调控中空二氧化硅纳米粒子的粒径和空腔体积分率,进而可精确调控减反射薄膜的厚度和折射率;通过酸洗工艺,将自组装次数由10次减少为2次,简化了涂膜的工艺条件,在最佳工艺条件下所制备的单层减反射薄膜在350-800 nm波长范围内可显著提高玻璃的透光率,在最佳波长（λ=520 nm）处将玻璃的透光率由91.6%提高至98.1%;双层减反射薄膜可在更宽的波段范围内提高基材的透光率,在400~1500 nm波长范围内将玻璃的透光率提高了5%以上。

磁性二氧化硅纳米粒子的制备及性能

为了克服磁性四氧化三铁纳米粒子易团聚、易氧化、耐酸性差等缺点,提高其在催化剂、靶向药物载体、生物分离、核磁共振成像、磁热疗等领域的利用效率,采用共沉淀法合成了四氧化三铁纳米粒子,然后以其为核用Stber法制备出二氧化硅包覆四氧化三铁的复合纳米粒子.对包覆前及包覆后的磁性纳米粒子分别进行了X射线衍射、透射电子显微镜、振动样品磁强计的表征,并研究了二氧化硅的包覆对四氧化三铁纳米粒子磁性和耐酸性的影响.实验结果表明:磁性四氧化三铁及磁性二氧化硅纳米粒子的粒径分别为约20 nm和40 nm;磁性四氧化三铁的磁饱和强度为5.7 emu/g,磁性二氧化硅纳米粒子的磁饱和强度也达到5.1 emu/g;此外,在稍微降低磁性的条件下,表面二氧化硅的包覆显著改善了四氧化三铁纳米粒子的分散性和耐酸性.