石墨烯在金属防护中的应用与展望

石墨烯(类)材料作为明星材料,是诸多应用领域的研究热点。主要从两个方面综述了石墨烯材料在金属腐蚀防护中的应用研究现状,简要概述了单纯的石墨烯薄膜用于金属防护的发展历程,并对该防护手段的弊端进行了分析与讨论,得出石墨烯薄膜不适合直接覆于金属表面用于防腐蚀的结论。详细介绍了石墨烯复合防护涂层的制备方法与性能,针对将石墨烯类材料作为填料改性防护涂层的研究现状,概括了该防护手段的缺点与改进策略,即通过在氧化石墨烯表面进行分子(硅烷偶联剂、聚合物单体等)修饰和表面覆盖纳米粒子(纳米Si O2、Al2O3、Ti O2颗粒等),达到增强石墨烯材料与防护涂层之间的相容性的目的。在此基础上,提出了"主动防护"的概念,构想出一种以石墨烯材料为基础的新型缓蚀剂纳米存储器,同时提出石墨烯材料的深层防护机制仍亟待解决。最后,立足于整个石墨烯行业,从工业化应用的角度出发,对石墨烯防护技术进行了展望。     

Ultra-thin double-walled carbon nanotubes: A novel nanocontainer for preparing atomic wires

Double-walled carbon nanotubes (DWCNTs) with high graphitization have been synthesized by hydrogen arc discharge. The obtained DWCNTs have a narrow distribution of diameters of both the inner and outer tubes, and more than half of the DWCNTs have inner diameters in the range 0.6–1.0 nm. Field electron emission from a DWCNT cathode to an anode has been measured, and the emission current density of DWCNTs reached 1 A/cm² at an applied field of about 4.3 V/μm. After high-temperature treatment of DWCNTs, long linear carbon chains (C-chains) can be grown inside the ultra-thin DWCNTs to form a novel C-chain@DWCNT nanostructure, showing that these ultra-thin DWCNTs are an appropriate nanocontainer for preparing truly one-dimensional nanostructures with one-atom-diameter.      

Amino‐terminated polylactide micelles with an external poly(ethylene oxide) corona as carriers of drug‐loaded anionic liposomes

Micelles were prepared from a mixture of NH₂‐terminated poly(l ‐lactide) and poly(d ,l ‐lactide)‐block‐poly(ethylene oxide) (molar ratio of 3:7). The micelles were complexed with bilayer lipid vesicles (liposomes) composed of anionic palmitoyloleoylphosphatidylserine and zwitterionic dioleoylphosphatidylcholine in a molar ratio of 3:7. The micelles and micelle–liposome complexes were characterized using dynamic light scattering, laser electrophoresis, fluorimetry, transmission electron microscopy, enzymatic hydrolysis and cell viability with the following main findings. (i) Average diameter of micelle cores was found to be 70 ± 10 nm. (ii) Each micelle carried ca 20 000 amino groups. (iii) In a pH 7 solution the impact of the protonated NH₂ groups in the total surface of micelles was negligible owing to their screening by bulky poly(ethylene oxide) blocks. (iv) The micelles were stable in slightly acidic and neutral aqueous solutions, but aggregated in slightly alkaline solutions. (v) The micelles showed no cytotoxicity up to 0.04 mg mL^?1 concentration (the maximum concentration in the experiment). (vi) Each micelle adsorbed ca 30 anionic liposomes loaded with the antitumor antibiotic doxorubicin; the liposomes retained their integrity upon binding with micelles. (vii) The initial micelles and the micelle–liposome complexes showed two‐week stability to enzymatic hydrolysis. © 2018 Society of Chemical Industry     

pH响应的TiO2基纳米容器的制备及缓蚀性能

目的 提高环氧树脂涂层对钢片的耐腐蚀性。方法 采用水热法和NaF刻蚀法合成了中空TiO₂纳米颗粒,以此为材料基底,在TiO₂内部封装了苯并三氮唑（BTA）缓蚀剂,并以正硅酸乙酯（TEOS）和3-氨丙基三乙氧基硅烷（APTES）为硅源,在封装BTA缓蚀剂的TiO₂外表面包覆了硅膜。采用扫描电子显微镜（SEM）、傅里叶变换红外光谱仪（FTIR）、X射线光电子能谱仪（EDS）、X射线粉末衍射仪（XRD）、热重分析仪（TGA）及紫外-可见吸收光谱仪（UV-Vis）等,对纳米容器（TiO₂@BTA@SiO₂）的微观形貌、物相和结构进行了表征,并通过UV-Vis测试了纳米容器在不同p H值（2、4、7）下BTA的释放行为。采用极化曲线测定了钢片在不含和含有修饰TiO₂的0.3%Na Cl溶液中不同p H值下的抗腐蚀行为。结果 pH=2时纳米容器中封装的BTA释放率最大,超过90%的BTA在24h内释放出来,腐蚀抑制率为80.7%。经交流阻抗（EIS）测试表明,在浸泡周...     

Engineering a tubular mesoporous silica nanocontainer with well-preserved clay shell from natural halloysite

The in situ synthesis of mesoporous nanotubes from natural minerals remains a great challenge.Herein,we report the successful synthesis of mesoporous silica nanotubes (MNTs) with a varying inner-shell thickness and a preserved clay outer shell from natural-halloysite nanotubes (HNTs).After the enlargement of the lumen diameter of the tubular aluminosilicate clay by acid leaching,uniform mesopores were introduced by a modified pseudomorphic transformation approach,while the clay outer shell was well-preserved.Using density functional theory calculations,the atomic structure evolution and the energetics during Al leaching and Si-OH condensation were studied in detail.After the leaching of Al ions from the HNTs,local structural changes from Al(Oh) to Al(V) at a medium leaching level and to Al(Td) at a high leaching level were confirmed.The calculated hydroxylation energy of two kinds of silica components in the acid-leached HNTs (the distorted two-dimensional silica source in the inner shell and the intact aluminosilicate structure in the outer shell) was 0.5 eV lower or 1.0 eV higher than that of bulk silica,which clarifies the different behavior of the silica components in the hydrothermal process.The successful synthesis of reactive MNTs from HNTs introduces a new strategy for the synthesis of mesoporous nanocontainers with a special morphology using natural minerals.In particular,MNT samples with numerous reactive Al(V) species and a specific surface area up to 583 m2/g (increased by a factor of 10) are promising drug-loading nanocontainers and nanoreactors.     

Zirconyl Hydrogenphosphate Nanocontainers for Flexible Transport and Release of Lipophilic Cytostatics,Insecticides, and Antibiotics

Administration of lipophilic drugs is often restricted by poor aqueous solubility (especially in blood), limited membrane permeability, uncontrolled drug leakage, and aggregation of lipophilic drugs. As a new nanocarrier concept, LC@ZrO(mdp)@ZrO(HPO₄) core@shell nanocontainers (LC: lipophilic cavity; mdp: monododecylphosphate) are presented. As a proof of concept, the nanocontainers are used to encapsulate different types of lipophilic molecules such as the fluorescent dye lumogen red (LR), the cytostatic drug irinotecan (ITC), the insecticide cypermethrin (CM), and the tuberculosis antibiotic benzothiazinone‐043 (BTZ). Synthesis strategy and material structure of the nanocontainers are discussed in detail. LR@ZrO(mdp)@ZrO(HPO₄), as the first example, shows intense red emission and successful incorporation of LR into the nanocontainers. As ex vivo application, CM@ZrO(mdp)@ZrO(HPO₄) nanocontainers can be used to repel and even kill mosquitoes or flies being in contact with the insecticide‐loaded nanocontainers. The drugs ITC and BTZ—after encapsulation in ITC@ZrO(mdp)@ZrO(HPO₄) and BTZ@ZrO(mdp)@ZrO(HPO₄) nanocontainers—show high activity at low cytotoxicity in in vitro studies against tumor cells (HeLa, SK‐Mel‐28, HTC116, A549, RAW264.7) and tuberculosis (Mycobacterium tuberculosis‐infected macrophages). Taken together, the different lipophilic molecules (LR, CM, ITC, BTZ) point to the adaptability and performance of the novel zirconyl hydrogenphosphate nanocontainer concept.     

Photo and pH dual-responsive polydiacetylene smart nanocontainer

Herein, a novel smart nanocontainer was developed by incorporating photo-responsive azobenzene derivative/cyclodextrin (Azo–CD) supramolecular complex into pH-responsive polydiacetylene (PDA) vesicles matrix. The designed nanocontainer exhibited excellent cell-toxicity, and the controlled release property response to external photo and pH stimuli. The photo-controlled inclusion and exclusion reaction between α-cyclodextrin (α-CD) and azobenzene moiety were used to act as the driving force to induce photo-triggered controlled release behavior of the designed nanocontainer. Moreover, the pH-responsive PDA vesicle matrix endowed the designed system with a controlled release property upon pH variation. The facile preparation procedures and their efficiency of response to the external stimuli render the novel smart nanocontainer potential candidate for future applications in remote controlled drug release.