水介质中纳米金刚石表面改性研究

对纳米金刚石在水介质中的分散进行了探讨,利用机械力和化学力共同作用,对纳米金刚石表面进行改性,从而实现纳米金刚石在水介质中的分散和稳定,采用不同的机械化学处理工艺,可以使得体系在酸性和碱性介质条件下均保护良好的分散。对表面改性过程进行了机理分析。     

纳米金刚石计算机磁头抛光液的研制及应用

用聚氧乙烯型非离子表面活性剂可有效分散纳米金刚石于油介质中,由此制得了纳米金刚石抛光液,探讨了纳米金刚石的分散机理,认为庞大的亲水性基团聚氧乙烯基象一巨大的屏障膜,使纳米金刚石颗粒在油中相互弹开,削弱颗粒间的相互作用能,阻止了纳米颗粒的重新团聚,从而实现了纳米金刚石在油中的稳定分散.本文研制的纳米金刚石抛光液应用于计算机磁头的精抛光,能降低计算机磁头表面粗糙度50%以上,解决了计算机磁头行业的技术难题.实验结果表明,纳米金刚石是一种理想的计算机磁头抛光材料.     

金刚石纳米颗粒合成技术及应用研究进展

金刚石纳米颗粒粉体材料作为一种具有超硬特性、化学稳定性、良好导热性和生物相容性等优良性能的重要功能材料,有望在超精密抛光、复合镀工艺、场发射材料、隐身材料、润滑油、涂料、医疗等领域得到广泛应用[1]。目前,金刚石纳米颗粒粉体工业化规模合成的方法有:静压合成金刚石单晶粉碎、动压冲击合成金刚石聚晶和爆轰法合成纳米金刚石团簇。结合应用需求进行金刚石颗粒与形貌的再加工、表面官能化,实现颗粒在应用介质中的均匀与稳定分散,是金刚石纳米     

改性纳米金刚石-铬（Ⅲ）复合镀中金刚石含量对镀层性能的影响

为研究纳米金刚石（UFD）含量对金刚石-铬（Ⅲ）复合镀层性能的影响,将UFD在水介质中分散改性后添加到三价铬镀液中进行复合电镀。采用扫描电镜、微磨损试验机和显微硬度计对三价铬电镀和UFD复合电镀所得镀层的微观形貌、耐磨性和硬度等性能进行了测试与表征。结果表明：加入少量十二烷基苯磺酸钠（SDBS）改性的UFD就能有效改善...     

激光法制备碳质纳米材料

通过介绍在气体和液体介质中激光与固体材料相互作用的过程,评述了激光在不同介质中发生物理化学现象的差异.与气相中相比,激光冲蚀液体中固体材料产生的气态等离子区受到了液体限制,在该区域会产生更高的气态密度、温度和压力,适合于亚稳相纳米晶的合成.同时评述了激光制备碳基纳米材料的进展.激光在气相和液相中均可制得碳纳米管,气相中适于制备结构完整的碳纳米管,而液相中有利于纳米金刚石的合成.激光冲蚀液体中的石墨靶制备的纳米金刚石粒径较大,辐照石墨悬浮液工艺不仅可以获得超细的纳米金刚石还可以获得线型碳.激光法制备的碳基纳米材料具有尺寸小、纯度高和形状多样性,在未来有着广泛的潜在应用价值.     

水介质中纳米CeO_2的表面电性研究

为改善纳米CeO2在水介质中的稳定分散,在分析纳米CeO2各种性质的基础上,研究了介质pH值、无机电解质、阴离子表面活性剂对纳米CeO2表面电性的影响,并对分散机理进行了分析。结果表明:添加无机电解质可以显著降低碱性水介质中纳米CeO2的ζ电位,对于改善纳米CeO2在碱性区域内的稳定性有较好的效果。     

弱碱性水介质中纳米CeO2的分散

在分析纳米CeO2各种性质的基础上,研究了不同分散剂对纳米CeO2的表面电性及平均粒度的影响,并对分散机理进行了分析。结果表明：添加无机电解质及组合使用离子型表面活性剂和非离子型表面活性剂可以使纳米CeO2在弱碱性水介质中保持良好的分散性。     

聚苯乙烯/纳米金刚石复合微球的制备及性能测定

以纳米金刚石为乳化剂,BPO为引发剂,利用Pickering效应成功合成得到了聚苯乙烯/纳米金刚石复合微球.XRD、TDA-DTA、TEM、BET以及FT-IR分别进行了结构表征.研究结果表明,在聚苯乙烯/纳米金刚石复合微球中,纳米金刚石晶体为立方相,聚苯乙烯为无定形态,颗粒径粒大约为40～70nm,分散较好,比较面积达到230m2/g,该复合材料具有良好热稳定性.进一步的力学系性能测定表明,随着聚苯乙烯/纳米金刚石复合微球添加应用,聚苯乙烯的拉伸强度、断裂伸长率性能得到了明显地改善,但弯曲强度性能有所下降.     

纳米TiO2的分散工艺及其改性水性涂料的性能

通过锐钛型纳米TiO2在水性介质中的分散试验,解决了纳米TiO2在水性介质的团聚问题,并研究了各因素对纳米TiO2水悬浮液稳定性的影响,通过正交试验筛选出最佳分散工艺为:100 mL水性介质中731分散剂0.5 g,偶联剂硅烷1.5 mL,纳米TiO2 0.5%(质量分数),pH值为7.5.将分散后的纳米TiO2浆料加入到普通水性苯丙乳液涂料中,并加入各种助剂,配制出了水性纳米TiO2涂料.对所配制涂料的性能测试结果表明,改性涂料的漆膜柔韧性和附着力提高,光泽、流平性、耐水性、耐碱性和耐擦洗性均优于普通涂料.     

化学处理法制备碳包铜导热纳米流体及其性能表征

氩电弧等离子体法制备碳包铜纳米粒子,采用双氧水化学处理和添加十二烷基苯磺酸钠两种方法制备碳包铜-水纳米流体,探讨了不同分散方法对碳包铜纳米流体导热性能的影响.结果表明,双氧水化学处理碳包铜纳米粒子制备水介质分散体系具有比添加分散剂制备分散体系更高的导热性能.采用化学处理法,添加质量分数为2.0%的碳包铜-水纳米流体导热...     

Polycrystalline diamond on self-assembled detonation nanodiamond: a viable route for fabrication of all-diamond preformed microcomponents

Surface assisted self-assembly of detonation nanodiamond particles (with typical sizes in the range 4-10?nm) has been obtained using different fractions of colloidal aqueous dispersions as starting material. The relationship between dispersion properties and structure/geometry of the aggregates deposited on Si or glass plates has been investigated. A series of differently shaped free-standing nanodiamond structures has been prepared, analysed and used as templates for the growth of polycrystalline diamond layers by the chemical vapour deposition (CVD) technique. The possibility of obtaining textured coating with a relatively strong [Formula: see text] preferred orientation (within a solid angle of about 0.6?srad) is also reported. Overall, the coupling of nanodiamond self-assembling to the CVD diamond growth enables one to produce specimens with complex 3D architectures. The proposed microfabrication methodology could represent a viable route for the production of free-standing all-diamond microcomponents, with tailored shapes and predefined crystalline features, to be used for advanced electronic applications.     

Covalent and noncovalent functionalisation and solubilisation of nanodiamond

Covalent functionalisation of nanodiamond has been carried out by employing several methods. One of them involves the reaction of acid-treated nanodiamond with thionyl chloride followed by reaction with a long-chain aliphatic amine to produce the amide derivative. The second method involves reaction of acid-treated nanodiamond with an organosilicon or organotin reagent such as hexadecyltrimethoxysilane, dibutyldimethoxytin, and perfluoro-octyltriethoxysilane. The products of covalent functionalisation produce excellent dispersions in CCl₄ and toluene. SiO₂–and SnO₂–covered nanodiamond are obtained by heating the nanodiamond coated with the organosilane and the organotin reagents, respectively. By interaction of nanodiamond with surfactants such as sodium bis(2-ethylhexyl) sulphosuccinate (AOT), Triton X-100 (TX-100), polyvinyl alcohol (PVA), cetyltrimethylammonium bromide (CTAB), and tert-octylphenoxy poly(oxyethylene)ethanol (IGEPAL) gives good dispersions in water, the best dispersion with the lowest surfactant concentration being obtained with IGEPAL.     

爆轰纳米金刚石在乙醇中分散性的研究

文章对自制的爆轰纳米金刚石的分散性进行了研究。以高分子聚合物为分散剂、无水乙醇做溶剂、超声作为分散手段进行了实验，得到了平均粒径51．7nm的胶体溶液。采用傅立叶转变红外光谱仪和动态光散射激光粒度仪对金刚石改性效果及分散稳定性做了表征。结果表明两种高聚物分散剂的复配使用可以明显提高纳米金刚石在乙醇中的分散稳定性，同时给出了可能的分散机理。     

Deaggregation of nanodiamond powders using salt- and sugar-assisted milling

Diamond particles of 5-10 nm in size can be produced in large quantities by denonating oxygen-lean explosives in a closed chamber. They have numerous useful properties and are used in applications ranging from lubricants to drug delivery. Aggregation of diamond nanoparticles is limiting wider use of this important carbon nanomaterial because most applications require single separated particles. We demonstrate that dry media assisted attrition milling is a simple, inexpensive, and efficient alternative to the current ways of deaggregating of nanodiamond. This technique uses water-soluble nontoxic and noncontaminating crystalline compounds, such as sodium chloride or sucrose. When milling is complete, the media can be easily removed from the product by water rinsing, which provides an advantage when compared to milling with ceramic microbeads. Using the dry media assisted milling with subsequent pH adjustment, it is possible to produce stable aqueous nanodiamond colloidal solutions with particles <10 nm in diameter, which corresponds to 1-2 primary nanodiamond particles. The study of milling kinetics and the characterization of the produced nanodiamond colloids led us to conclude that aggregates of less than 200 nm in diameter, observed at the tail of the pore size distribution of milled nanodiamond, are loosely bonded and rather dynamic in nature. Color change observed in ND colloids upon shifting their pH toward the basic end allowed us to demonstrate that the coloration comes from the light interaction with colloidal particles and not from an increase in nondiamond carbon content.     

Zwitterion‐Functionalized Detonation Nanodiamond with Superior Protein Repulsion and Colloidal Stability in Physiological Media

Nanodiamond (ND) is a versatile and promising material for bioapplications. Despite many efforts, agglomeration of nanodiamond and the nonspecific adsorption of proteins on the ND surface when exposed to biofluids remains a major obstacle for biomedical applications. Here, the functionalization of detonation nanodiamond with zwitterionic moieties in combination with tetraethylene glycol (TEG) moieties immobilized by click chemistry to improve the colloidal dispersion in physiological media with strong ion background and for the simultaneous prevention of nonspecific interactions with proteins is reported. Based on five building blocks, a series of ND conjugates is synthesized and their performance is compared in biofluids, such as fetal bovine serum (FBS) and Dulbecco's modified Eagle medium (DMEM). The adsorption of proteins is investigated via dynamic light scattering (DLS) and thermogravimetric analysis. The colloidal stability is tested with DLS monitoring over prolonged periods of time in various ratios of water/FBS/DMEM and at different pH values. The results show that zwitterions efficiently promote the anti‐fouling properties, whereas the TEG linker is essential for the enhanced colloidal stability of the particles.     

Mass production and dynamic imaging of fluorescent nanodiamonds

Fluorescent nanodiamond is a new nanomaterial that possesses several useful properties, including good biocompatibility, excellent photostability and facile surface functionalizability. Moreover, when excited by a laser, defect centres within the nanodiamond emit photons that are capable of penetrating tissue, making them well suited for biological imaging applications. Here, we show that bright fluorescent nanodiamonds can be produced in large quantities by irradiating synthetic diamond nanocrystallites with helium ions. The fluorescence is sufficiently bright and stable to allow three-dimensional tracking of a single particle within the cell by means of either one- or two-photon-excited fluorescence microscopy. The excellent photophysical characteristics are maintained for particles as small as 25 nm, suggesting that fluorescent nanodiamond is an ideal probe for long-term tracking and imaging in vivo, with good temporal and spatial resolution.     

Direct deposition of patterned nanocrystalline CVD diamond using an electrostatic self-assembly method with nanodiamond particles

Micron-sized and precise patterns of nanocrystalline CVD diamond were fabricated successfully on substrates using dispersed nanodiamond particles, charge connection by electrostatic self-assembly, and photolithography processes. Nanodiamond particles which had been dispersed using an attritional milling system were attached electrostatically on substrates as nuclei for diamond growth. In this milling process, poly sodium 4-styrene sulfonate (PSS) was added as an anionic dispersion agent to produce the PSS/nanodiamond conjugates. Ultra dispersed nanodiamond particles with a ζ-potential and average particle size of - 60.5 mV and ～ 15 nm, respectively, were obtained after this milling process. These PSS/nanodiamond conjugates were attached electrostatically to a cationic polyethyleneimine (PEI) coated surface on to which a photoresist had been patterned in an aqueous solution of the PSS/nanodiamond conjugated suspension. A selectively seeded area was formed successfully using the above process. A hot filament chemical vapor deposition system was used to synthesize the nanocrystalline CVD diamond on the seeded area. Micron-sized, thin and precise nanocrystalline CVD diamond patterns with a high nucleation density (3.8 ± 0.4 × 10(11) cm(-2)) and smooth surface were consequently fabricated.     

纳米金刚石掺混对碳纳米管薄膜场发射性能的影响

为了提高碳纳米管（CNT）阴极膜的场发射均匀性和稳定性,同时改善CNT膜的制作过程,本文提出一种掺混纳米金刚石（D）制作高性能丝网印刷CNT膜的方法．通过掺混碳相纳米金刚石,形成结构匹配的CNT／D复合膜,CNT膜内的间隙势垒减少,发射体分散更均匀,膜层与基底接触面积增加;同时,结合纳米金刚石的负电亲和势和场发射特性,可有效提高CNT阴极膜的导电性,增大有效发射体的密度．场发射特性测试表明CNT／D复合膜能得到1．89V／μm的低开启电场,在2．8V／μm场强下,场发射电流密度远高于普通CNT膜,达到463μA／cm2,与普通CNT阴极膜相比,CNT／D复合膜的场发射稳定性显著提高,在400℃热处理后CNT／D膜激发阳极发光更均匀．     

GOX-functionalized nanodiamond films for electrochemical biosensor

The importance of nanodiamond in biological and technological applications has been recognized recently, and applied in drug delivery, biochip, sensors and biosensors. Under this investigation, nanodiamond (ND) and nitrogen doped nanodiamond (NND) were deposited on n-type silicon films, and later functionalized with enzyme Glucose oxidase (GOX). The GOX functionalized doped and undoped ND films were characterized using combination of several techniques; i.e. FTIR spectroscopy, Raman spectroscopy, atomic force microscopy (AFM) and electrochemical techniques. ND/GOX and NND/GOX thin films on n-type silicon have been found to provide sensitive glucose sensor. GOX has been chosen as a model enzyme system to functionalize with ND at molecular level to understand the glucose biosensor.     

Raman spectroscopy of amorphous, nanostructured, diamond-like carbon, and nanodiamond

Raman spectroscopy is a standard characterization technique for any carbon system. Here we review the Raman spectra of amorphous, nanostructured, diamond-like carbon and nanodiamond. We show how to use resonant Raman spectroscopy to determine structure and composition of carbon films with and without nitrogen. The measured spectra change with varying excitation energy. By visible and ultraviolet excitation measurements, the G peak dispersion can be derived and correlated with key parameters, such as density, sp(3) content, elastic constants and chemical composition. We then discuss the assignment of the peaks at 1150 and 1480 cm(-1) often observed in nanodiamond. We review the resonant Raman, isotope substitution and annealing experiments, which lead to the assignment of these peaks to trans-polyacetylene.