Macro-micro relationship in nanostructured functional composites
无机纳米相_纳米纤维素杂化纳米材料的研究进展_吴巧妹
以 NCC 为基体和稳定剂，
Ag 合金相NCC 复合物。 用 NaBH4 为还原剂， 原位制备了含有不同化学组成的纳米粒子 Au近年来， 由于银纳米粒子（ AgNPs） 较低的生理毒性及其对多数细菌、 真菌、 霉菌、 孢子等微生物的强 效杀菌活性而广受青睐。选择无毒、 生物相容性佳、 比表面积大的纳米纤维素作为 AgNPs 的分散介质， 可以大大减少 AgNPs 之间的团聚， 从而使 AgNPs 的高效抗菌性得到充分发挥。Fortunati 等
或 CO2 超临界干燥技术处理 NCC 水凝胶， 可以制备获得机械性能良好且高孔隙率 （ ＞ 98% ） 的低密度
［12 ］ NCC 气凝胶， 并有望被进一步应用于光控吸附、 漂浮体、 湿度传感和磁功能材料等领域。 Kettunen 等
以钛酸异丙酯为前驱体， 利用化学气相沉积 （ CVD ） 法成功地实现了 NCC 气凝胶骨架的无机功能化改 性。经 TiO2 纳 米 涂 层 改 性 的 NCC 气 凝 胶 呈 现 出 优 异 的 光 响 应 润 湿 性 能 （ photoswitchable wetting NCC 气凝胶在超疏水状态与超亲水状态之 property） 。通过紫外线辐照的 “开关 ” 控制， 可以实现 TiO2 间的可逆切换（ 图 1 ） 。他们推测这种奇特的性质与冷冻干燥生成的 NCC 气凝胶具有多尺度聚集体结 NCC 气凝胶的微构密切相关： 稳态 TiO2 纳米多级结构或微粗糙表面结构对气泡有稳定作用而呈现超 NCC 气凝胶毛细管效应增强而转变成 TiO2 涂层的结构缺陷增加， 疏水性； 经紫外线照射后， 致使 TiO2 超吸水性。另外， 经 TiO2 修饰的 NCC 气凝胶同样具有光催化活性， 结合它的光调控润湿性能， 预示其 在微流体器件和水体系污染控制领域可能大有作为 。
金属基复合材料的微屈服行为
第20卷 第4期Vol 120 No 14材 料 科 学 与 工 程Materials Science &Engineering总第80期Dec.2002文章编号:10042793X (2002)0420594203收稿日期:2002204224;修订日期:2002206211基金项目:国家自然科学基金资助项目(19972021)作者简介:吴晶(1974—),男,广东清远人,博士生,从事金属基复合材料细观力学研究.金属基复合材料的微屈服行为吴 晶,李文芳,蒙继龙(华南理工大学机械工程学院,广东广州 510641) 【摘 要】 金属基复合材料(M MC )的微屈服行为有其特殊性,主要表现在基体中的热残余应力水平和位错组态与宏观屈服阶段显著不同,因而表现出的力学行为也不同。
本文综述了金属基复合材料微屈服行为的宏观表现和微观特性,并对其研究发展进行了概述,指出了有待深入研究的问题。
【关键词】 金属基复合材料;微屈服;位错;热残余应力中图分类号:TG 151 文献标识码:AMicroyield B ehavior of Metal Matrix CompositesWU Jing ,LI Wen 2feng ,MENG Ji 2long(School of Mech anical E ngineering ,South China U niversity of T echnology ,G u angzhou 510641,China)【Abstract 】 During the M MC ’s microyield process the residual stress level and dislocation con figuration in the matrix is quite differ 2ent rom those in its macroscopical process.S o its mechanical behavior is quite different als o.This paper summarizes the M MC ’s microyield behavior ’s macroscopical behavior ,microcosmic characteristic and the development level.The problems to be further studied were pointed out too.【K ey w ords 】 metal matrix composite ;microyield ;dislocation ;thermal residual stress1 前 言材料的微屈服行为是指塑性应变很小时材料的应力与应变关系(通常指(1～2)×10-6残余应变量),它反映了材料在微小变形量情况下抵抗塑性变形的能力[1]。
jz100978u-BiVO4
Reducing Graphene Oxide on a Visible-Light BiVO4 Photocatalyst for an Enhanced Photoelectrochemical Water SplittingYun Hau Ng,†,§Akihide Iwase,†,§Akihiko Kudo,‡and Rose Amal*,††ARC Centre of Excellence for Functional Nanomaterials,School of Chemical Engineering,The University of New South Wales, Sydney,NSW2052,Australia,and‡Department of Applied Chemistry,Faculty of Science,Tokyo University of Science,1-3Kagurazaka,Shinjuku-ku,Tokyo162-8601,JapanABSTRACT Bismuth vanadate(BiVO4)is incorporated with reduced grapheneoxide(RGO)using a facile single-step photocatalytic reaction to improve its photo-response in visible light.Remarkable10-fold enhancement in photoelectrochemi-cal water splitting reaction is observed on BiVO4-RGO composite compared withpure BiVO4under visible illumination.This improvement is attributed to the longerelectron lifetime of excited BiVO4as the electrons are injected to RGO instantly atthe site of generation,leading to a minimized charge recombination.Improvedcontact between BiVO4particles with transparent conducting electrode using RGOscaffold also contributes to this photoresponse enhancement.SECTION Energy Conversion and StorageT he demand for clean energy technology has triggered research in nanostructured semiconductor films for solarcells,water splitting,and environmental remediation application.1-6Of particular interest are titanium dioxide (TiO2)particulate films synthesized using various methods including the hydrothermal and anodization methods.7-9To date,TiO2serves as the benchmark material for many photo-conversion processes.Despite initial success in achieving considerable efficiency in converting light energy into useful chemicals and electricity,TiO2activation limited to UV light only has substantially hampered its relevance in a genuine solar light energy conversion application.From the viewpoint of solar energy utilization,the development of photocatalysts capable of photoinduced charge separation upon excitation in the visible spectral region is emerging as the important research direction in this field.10-12Bismuth vanadate(BiVO4)has been an ideal visible light-driven semiconductor with narrow band gap energy of2.4eV (λ<520nm).13It intrinsically has sufficient absorption within the solar spectrum and stability against photocorrosion. Furthermore,it is inexpensive,environmentally benign,and can be synthesized using numerous facile methods.Sayama et al.prepared BiVO4thin film on fluorinated tin oxide(FTO) transparent electrode with an improved contact between BiVO4and the FTO using metal-organic decomposition method.14They also reported that the silver ion treatment of BiVO4enhanced the visible light photocurrent generation by∼3times.15Kisch and coworkers modified BiVO4with p-type cobalt oxide to form a p-n junction within the compo-site that improved the charge separation efficiency.16Grimes recently demonstrated that the photoelectrochemical proper-ties of BiVO4could be adjusted by changing the structure of BiVO4from nanowire to nanopyramid.17We have also de-monstrated photoelectrochemical water splitting using BiVO4 electrodes to be influenced by the contact between photo-catalysts and FTO probed by BiVO4with various sizes.18As the basis for thin-film photoanode in photoelectrochemical pro-cess,in general,pure BiVO4falls short on one main principal barrier,namely,the high charge-carrier's recombination rate. Transport of photogenerated electrons across the particle network randomly exposes them to many grain boundaries and recombination centers prior to their collection at the electrode surface.This phenomenon results in only modest photocurrent generated in the pure BiVO4film.In searching for new tools to enhance photoactivity of semiconductors,the graphene-based nanocomposite system has stood out as recent studies have shown its usefulness in electronics,catalysis,and photovoltaic devices.19-21Owing to the abundance of delocalized electrons from the conjugated sp2-bonded carbon network,graphitic carbon enhances the transport of electrons photogenerated in semiconductor par-ticles,leading to an increase in the photoconversion efficiency of the system.Graphene-based metal or semiconductor nanocomposites are generally synthesized using graphene oxide(GO)as the precursor,followed by its chemical reduc-tion to reduced graphene oxide(RGO).Various methods have been reported,and the use of toxic reducing agent hydrazine or high temperature is sometimes unavoidable.22,23Kamat et al.recently discovered an alternative facile photocatalytic Received Date:July19,2010Accepted Date:August12,2010Published on Web Date:August17,2010reduction method to convert GO to RGO at room temperature using TiO2and ZnO as the photocatalysts:GO undergoes reduction when it accepts electrons from the excited TiO2and ZnO.24,25Because TiO2and ZnO possess highly negative conduction band energy,upon excitation with UV irradiation, transfer of photogenerated electrons from their conduction bands to GO takes place ing this photocatalytic method,we have recently reported the constructive effect of incorporating RGO into TiO2thin film to doubling the photo-electrochemical and photocatalytic performance.26Several groups have also explored the graphene-TiO2composites in photocatalysis and dye-sensitized solar cells.27-29 However,the applicability of this photocatalytic reduction of GO has not yet been proven in a wider context of photo-catalysis.Although visible light active BiVO4is known for its strong oxidizing ability,its conduction band energy is much lower than its UV active counterparts.Because of the weaker driving force to inject electrons from excited BiVO4to GO in visible light irradiation,the not-yet-defined effectiveness of this reaction aroused our interest in obtaining a better under-standing of this system.In this Letter,we present the practi-cability of using a visible light photocatalyst(BiVO4)to reduce GO to RGO photocatalytically to yield a BiVO4-reduced gra-phene oxide(BiVO4-RGO)composite.Photoelectrodes made by this composite material exhibited improved charge trans-port properties,leading to a remarkable enhancement invisible light response.The effectiveness of the BiVO4-RGO photoelectrodes for water splitting is also demonstrated. BiVO4-RGO has been successfully synthesized using BiVO4-graphene oxide(BiVO4-GO)as the precursor composite.30,31 (See the Supporting Information for experimental details.) When BiVO4-GO particles are suspended in ethanol solu-tion,followed by irradiation with visible light,electron-hole pairs are generated on the surface of the BiVO4.The positive holes are consumed by ethanol as the holes scavenger, leaving the photogenerated electrons to be injected into GO. As the photoirradiation continues for10min,the yellowish-greenish suspension gradually turns into a dark-green solu-tion(Figure1a).Kamat and coworkers have previously obser-ved the similar color change from light-brown to dark-brown in an analogous UV-triggered TiO2-GO system and attri-buted it to the partial restoration of theπ-network within the graphitic carbon structure.24This color change has also been evident during chemical reduction of GO to RGO using hydrazine as reductant.32Therefore,similar reduction of GO to RGO is assumed to occur in the visible light BiVO4 photocatalytic system.The successful reduction of GO dur-ing the irradiation is confirmed by analyzing the resultant dried powder of irradiated BiVO4-GO using X-ray photo-electron spectroscopy(XPS)and X-ray diffraction(XRD). Figure1b shows the XPS spectra of BiVO4-GO(before irradiation),BiVO4-RGO(after irradiation),and BiVO4-RGO reduced by hydrazine.In brief,the C1s XPS spectrum of BiVO4-GO clearly indicates a considerable degree of gra-phene oxidation with three main components that corres-pond to carbon atoms in different functional groups:the nonoxygenated C-C bond(284.5eV),the C-O(epoxy and hydroxyl)(286.6eV),and the carboxylate C d O from car-boxylic acid(288.9eV).After3h of irradiation,the peak intensity for C-O bonds in the C1s XPS spectrum decreased well below than that of the as-prepared BiVO4-GO.This indicates that an efficient deoxygenation of GO occurred through the injection of photogenerated electrons from ex-cited BiVO4to GO.Note that the identical Bi4f and V2p XPS peak positions and intensities for BiVO4and BiVO4-RGO excluded the hybridization of BiVO4band structure with RGO. (See Figure SI1of the Supporting Information.)To examine the effectiveness of this BiVO4photocatalytic reduction reac-tion,we performed a chemical reduction of GO by hydrazine for comparison.Although hydrazine almost completely redu-ces GO to RGO as expected,it introduces a significant pre-sence of C-N bonding(285.8eV),33which may affect the restoration of the conjugatedπ-network of graphene.The formation and preservation of the BiVO4active crystal structure before and after photoirradiation with GO is clearly shown by XRD analysis(Figure1c).Samples both before and after photoirradiation are highly crystallized and exhibited peaks at around19.5,29,and30.5°,which can be indexed to the scheelite structure of BiVO4with active monoclinic phase. This is the most active phase for O2evolution under visible light irradiation.34Although we could not observe any peak of GO from the sample shown in Figure1a owing to its trace concentration of5wt%,we observed a new diffraction peak at12°when the amount of GO was significantly increased to 50wt%.This peak was aroused from the(001)plane of GO, and its calculated interlayer distance of0.74nm agrees well with the literature.35After photocatalytic reduction by excited BiVO4,the intensity of the peak at12°dropped profoundly to an almost undetectable level,suggesting the structural changes of the(001)plane of GO attributed to the loss of oxygen functional groups,as supported by XPS data.36Onthe Figure1.(a)Photographs,(b)XPS spectra,and(c)XRD diffracto-grams of BiVO4-GO,BiVO4-RGO,and BiVO4-RGO reduced by hydrazine(only in part b).basis of the identical peak positions and intensities for BiVO4 components in all samples,the introduction of GO to the synthesis and the successive photocatalytic reduction of GO do not alter the crystallinity and phases of BiVO4.This is a crucial factor when identifying the effect of RGO in its photo-electrochemical properties.Figure2a shows the morphology of the synthesized BiVO4 and BiVO4-RGO composites under a field-emission SEM microscope.Pure BiVO4synthesized using the solid-liquid phase reaction of bismuth nitrate and vanadium oxide under acidic conditions possesses large particle sizes ranging from 150to500nm.The particles seize smooth surfaces and appear to aggregate.When GO was introduced to the system,inter-action between its oxygen-functional groups,especially the carboxylic species,and the hydroxyl groups of oxide mate-rials led to the dispersion and adhesion of BiVO4particles on GO sheets.37This intimate interaction enables the electron transfer from BiVO4to GO during the photoexcitation process. Careful examination of the SEM image reveals the BiVO4 being comprehensively integrated within the matrix of RGO; that is,the particles are seen deposited on top of as well as underneath the slightly transparent RGO.(See Figure SI2of the Supporting Information for pure RGO SEM image.)This nanostructure enables a multichannel environment to facili-tate the efficient charge interaction within the composite.We obtained uniform thin films of BiVO4and BiVO4-RGO by dropcasting0.5g/L of particles suspended in ethanol onto FTO transparent electrodes.Figure2b shows photo-graphs of the pure BiVO4and BiVO4-RGO photoelectrodes. Using suspension with concentration higher than0.5g/L caused the formation of uneven films with significant surface roughness.These homogeneous thin film photoelectrodes are robust in both acidic and basic media,even under stirring and purging conditions.The microscopic feature of the dropcasted nanocomposite thin films(Figure SI3of the Supporting In-formation)exhibited essentially identical morphological char-acteristics as its powdery dispersed counterpart:the RGO flakes are seen well-decorated with BiVO4particles.Most importantly, surface contact between the RGO flake and FTO is established because this is crucial in shuttling photogenerated electrons from excited BiVO4to the external circuit,which is further discussed below.When subjected to excitation with visible light(E g>2.4eV) in a standard three-compartment cell,BiVO4and BiVO4-RGO films undergo charge separation;then,the electrons flow through the circuit,thus generating photocurrent.Magnitude of the anodic photocurrent,generated by the films,charac-terizes the electrons collection efficiency at the FTO collecting electrode.Figure3a shows the voltage-current functions of BiVO4and BiVO4-RGO during repeating ON-OFF illumina-tion cycles.Both samples exhibit prompt and reproducible photocurrent,whereas a controlled experiment using only RGO film does not generate any ing a dropcast method,BiVO4thin film generates a low photocur-rent density(∼8μA cm-2),which is consistent with those observed in other laboratories.16,18Other works showed that pressuring the thin film at200kg cm-2or directly growing BiVO4on conducting electrode can improve the adhesion of BiVO4to the conducting electrode,thus improving the photo-current generation(ranging from tens of microamperes to millamperes per square centimeter).14,16Overall,photo-current generation of the BiVO4-RGO photoelectrode sur-passes those generated by pure BiVO4.Magnitude of the saturated photocurrent density generated in BiVO4-RGO (∼70μA cm-2)is nearly one order larger than that of pure BiVO4.Interestingly,a UV-excited TiO2(Degussa P25)photo-electrode with the same surface density prepared under similar experimental conditions produces less photocurrent density(∼50μAcm-2)than the visible light-triggered BiVO4-RGO.This significant improvement of BiVO4in generating a competent visible light response is of great importance in designing efficient visible light photoelectrochemical solar cells and photocatalysts.In a separate experiment of water splitting reaction,H2and O2evolution measurements were conducted in a two-electrode system using0.1M Na2SO4electrolyte solution,and an external bias voltage of0.8V between Pt counter electrode and BiVO4or BiVO4-RGO photoanode was applied.Photo-excited electrons flow through an external circuit to the Pt wire to reduce H2O to H2,whereas photogenerated holes (hþ)are consumed for water oxidation on the photoanode.A negligible amount of gas,beyond the limitation of quanti-fication,was observed on pure BiVO4,whereas a steady evolution of H2and O2was quantified on BiVO4-RGO atthe Figure2.(a)SEM images and(b)photographs of BiVO4and BiVO4-RGO.Scale bars correspond to600nm.rate of 0.75and 0.21μmol h -1,respectively.The successful splitting of water using an external bias at 0.8V in this system,lower than the theoretical value of 1.23V,illustrates that the uphill reaction occurs through light energy conver-sion.These results are evidence of the constructive effect of the RGO in promoting electron shuttling and suppressing charge recombination to realize improved utilization of charge carriers for the overall water splitting reaction.The slight deviation from the stoichiometric ratio of hydrogen to oxygen generated is possibly due to the consumption of small amounts of h þby the RGO.Further investigations in the stability of RGO in the presence of various holes scaven-gers are now in progress.The incident photon-to-current-conversion efficiency (IPCE )of BiVO 4-RGO and their diffuse reflectance spectra is recor-ded in Figure 3b.Photocurrent action spectra were recorded at 0.75V versus Ag/AgCl with a monochromatic excitation source.IPCE action spectra determine the amount of photo-generated electrons collected at the contact per photon irradiated on the photoelectrochemical cell surface and are calculated by normalizing the photocurrent values with incident light energy and intensity.Both samples demon-strate a photocurrent onset at 520nm corresponding to the band gap of BiVO 4.The onset measured in IPCE fits well with the diffuse reflectance spectra,indicating that the photo-current generation occurs upon band gap photoexcitation of BiVO 4.This would exclude the possibility of the excited RGO playing the role of the electron source in generating photo-current.In the absence of RGO,a trivial IPCE of BiVO 4at 0.3%(at 400nm )was observed,whereas the IPCE response shows a remarkable enhancement to 4.2%when RGO is incorporated.One order of magnitude enhancement inphotoconversion efficiency indicates the improved charge collection efficiency in the presence of RGO.Inset in Figure 4shows the typical photocurrent transient profile of the BiVO 4and BiVO 4-RGO electrodes at a constant potential.Transient of photocurrent has been employed to study the charge recombination behavior of a semicon-ductor electrode,38and it can be normalized by defining the parameter asD ¼ðI ðt Þ-I ðst ÞÞ=ðI ðin Þ-I ðst ÞÞð1Þwhere I (t )is the photocurrent at a time t ,I (in )is the initialphotocurrent at t =0,and I (st )is the steady-state photo-current.T afalla et al.defined the transient time constant,τ,as the time at which ln D =-1.39Figure 4shows the plots of ln D versus time for photo-current transient responses of BiVO 4and BiVO 4-RGO photo-electrodes biased at 0.75V.For BiVO 4,τ=2.8s,compared with BiVO 4-RGO,τ=7.6s,and it is a general observation that τis larger in BiVO 4-RGO in the entire range of applied bias,which reflects the slower recombination process in BiVO 4-RGO photoelectrode.The decay time (in the range of seconds )is comparable to that of the colloidal TiO 2electrodes reported by Hagfeldt et al.38Although the recombination mechanisms cannot be concluded from these measurements,it elucidates that the significant enhancement in IPCE and water splitting reaction on BiVO 4-RGO film are owing to its slower charge recombination rate.In general,photoactivity of BiVO 4is limited by its rapid charge recombination upon excitation,thus limiting the charge carriers'contribution to the overall photocurrent generation and photocatalytic reaction.Charge recombination is promoted by the existence of many grain boundaries among semiconductor particles as well as poor contact with the flat FTO surface due to its 3D shape,as indicated by the SEM images in Figure SI1a of the Supporting Information.Photogenerated electrons have to diffuse through countless recombination centers prior to reaching the FTO electrode,resulting in the loss of the vast majority of these charge carriers.By providing a low-resistant electrons path-way,the presence of RGO facilitates efficient electron trans-fer from excited BiVO 4particles to the FTOelectrode,Figure 3.(a )Visible light voltage -photocurrent functions of BiVO 4,BiVO 4-RGO,and TiO 2(under UV irradiation ).(b )IPCE and diffuse reflectance spectra of BiVO 4and BiVO 4-RGO.Figure 4.Normalized plots of the photocurrent -time depen-dence for both BiVO 4and BiVO 4-RGO electrodes.Inset represents a typical photocurrent transient response curve at a constant potential.whereas the RGO itself does not directly participate in the charge generation.Combining the physical and electrochemical characteriza-tions allows the mechanism of improved electrons transport in the BiVO 4-RGO film to be postulated (Figure 5).The pri-mary step in the process is the photoinduced charge separa-tion within BiVO 4particles,followed by the transfer of elec-trons to RGO sheets and then to the collecting electrodes.It is reasonable to consider that the electron transfer from BiVO 4to RGO proceeds readily,given the flatband potential of -0.30and ∼0V versus NHE for BiVO 4and graphene at pH 7,respectively.16Previous studies have also shown that RGO serves excellently as electron acceptor and mediator .40In addition,RGO sheets also provide better media for the dis-persion of BiVO 4particles and improve contact with flat FTO surface.As intimate surface contact being established be-tween RGO and FTO during the film fabrication (Figure SI1b of the Supporting Information ),electrons injected from BiVO 4are quickly transported to the collecting electrode through the presence of the large pool of delocalized electrons from its π-πgraphitic carbon network.The results presented in this study highlight the constructive effect of incorporating BiVO 4with RGO in the photoelectro-chemical water splitting reaction.We have demonstrated the feasibility of using BiVO 4visible light photocatalyst to reduce GO photocatalytically .Usefulness of RGO in promoting charge col-lection and charge transport by accepting photogenerated elec-trons from BiVO 4and shuttling them to the collecting electrode,yielding an enhancement in IPCE as great as one-order of magni-tude,has been proven.The BiVO 4-RGO system also generates higher photocurrent density in visible light than that generated by the TiO 2system in UV light.Moreover ,significant H 2and O 2evolution was seen in the BiVO 4-RGO photoelectrochemical water splitting cell,whereas negligible gas evolution was obser-ved in the pure BiVO 4cell,showing the greatadvancement of the synthesized BiVO 4-RGO composite for water splitting.SUPPORTING INFORMA TION AVAILABLE Experimentaldetails,SEM images of pure RGO and photoelectrodes,relation-ship between photocurrent transient and recombination process,V 2p and Bi 4f XPS spectra,and Raman spectroscopy analysis.This mate-rial is available free of charge via the Internet at .AUTHOR INFORMATION Corresponding Author:*To whom correspondence should be addressed.E-mail:r.amal@.au.Author Contributions:§These authors contributed equally.ACKNOWLEDGMENT We thank the Australian Research Councilfor its financial support.Y .H.N.thanks Prof.Prashant V.Kamat from the University of Notre Dame for assistance and advice in estab-lishing the experimental procedures for BiVO 4-graphene photo-catalytic synthesis.Dr.Bill Gong from Solid State &Elemental Analysis Unit of UNSW is gratefully acknowledged for his help in XPS measurement and analysis.REFERENCES(1)Gao,F .;Wang,Y .;Shi,D.;Zhang,J.;Wang,M.;Jing,X.;Humphry-Baker,R.;Wang,P .;Zakeeruddin,S.M.;Gratzel,M.Enhance the Optical Absorptivity of Nanocrystalline TiO 2Film with High Molar Extinction Coefficient Ruthenium Sensitizers for High Performance Dye-Sensitized Solar Cells.J.Am.Chem.Soc.2008,130,10720–10728.(2)Lancelle-Beltran,E.;Prene,P .;Boscher,C.;Belleville,P .;Buvat,P .;Sanchez,C.All-Solid-State Dye-Sensitized Nanoporous TiO 2Hybrid Solar Cells with High Energy-Conversion Efficiency.Adv.Mater.2006,18,2579–2582.(3)Gan,W .Y .;Chiang,K.;Brungs,M.;Amal,R.;Zhao,H.Dense TiO 2Thin Film:Photoelectrochemical and Photocatalytic Properties.Int.J.Nanotechnol.2007,4,574–587.(4)Wolcott,A.;Smith,W .A.;Kuykendall,T .R.;Zhao,Y .;Zhang,J.Z.Photoelectrochemical Study of Nanostructured ZnOThin Films for Hydrogen Generation from Water Splitting.Adv.Funct.Mater.2009,19,1849–1856.(5)Mohapatra,S.K.;Misra,M.;Mahajan,V.K.;Raja,K.S.A Novel Method for the Synthesis of Titania Nanotubes Using Sono-electrochemical Method and Its Application for Photoelec-trochemical Splitting of Water.J.Catal.2007,246,362–369.(6)Gan,W .Y .;Zhao,H.;Amal,R.Photoelectrocatalytic Activity of Mesoporous TiO 2Thin Film Electrodes.Appl.Catal.,A 2009,354,8–16.(7)Oekermann,T .;Zhang,D.;Yoshida,T .;Minoura,H.Electron Transport and Back Reaction in Nanocrystalline TiO 2Films Prepared by Hydrothermal Crystallization.J.Phys.Chem.B 2004,108,2227–2235.(8)Mor,G.K.;Varghese,O.K.;Paulose,M.;Grimes, C.A.Transparent Highly Ordered TiO 2Nanotubes Arrays via Anodization of Titanium Thin Films.Adv.Funct.Mater.2005,15,1291–1296.(9)Gan,W .Y .;Lam,S.W .;Chiang,K.;Amal,R.;Zhao,H.;Brungs,M.P .Novel TiO 2Thin Film with Non-UV Activated Super-wetting and Antifogging Behaviours.J.Mater.Chem.2007,17,952–954.(10)Youngblood,W .J.;Anna Lee,S.-H.;Maeda,K.;Mallouk,T .E.Visible Light Water Splitting Using Dye-Sensitized Oxide Semiconductors.Acc.Chem.Res.2009,42,1966–1973.Figure 5.Electron transport in a photoelectrochemical cell based on BiVO 4and reduced graphene oxide.(11)Kudo,A.;Miseki,Y.Heterogeneous Photocatalyst Materialsfor Water Splitting.Chem.Soc.Rev.2009,38,253–278. (12)Yamasita,D.;T akata,T.;Hara,M.;Kondo,J.N.;Domen,K.Recent Progress of Visible-Light-Driven Heterogeneous Photocatalysts for Overall Water Splitting.Solid State Ionics 2004,172,591–595.(13)Kudo,A.;Omori,K.;Kato,H.A Novel Aqueous Process forPreparation of Crystal Form-Controlled and Highly Crystal-line BiVO4Powder From Layered Vanadates at Room Tempe-rature and Its Photocatalytic and Photophysical Properties.J.Am.Chem.Soc.1999,121,11459–11467.(14)Sayama,K.;Nomura,A.;Zou,Z.;Abe,R.;Abe,Y.;Arakawa,H.Photoelectrochemical Decomposition of Water on Nanocrys-talline BiVO4Film Electrodes Under Visible Light.Chem.Commun.2003,2908–2909.(15)Sayama,K.;Nomura,A.;Arai,T.;Sugita,T.;Abe,R.;Yanagida,M.;Oi,T.;Iwasaki,Y.;Abe,Y.;Sugihara,H.Photoelectro-chemical Decomposition of Water into H2and O2on Porous BiVO4Thin-Film Electrodes under Visible Light and Signifi-cant Effect of Ag Ion Treatment.J.Phys.Chem.B2006,110, 11352–11360.(16)Long,M.;Cai,W.;Kisch,H.Visible Light Induced Photoelec-trochemical Properties of n-BiVO4and n-BiVO4/p-Co3O4.J.Phys.Chem.C2008,112,548–554.(17)Su,J.;Guo,L.;Yoriya,S.;Grimes,C.A.Aqueous Growth ofPyramidal-Shaped BiVO4Nanowire Arrays and Structural Characterization:Application to Photoelectrochemical Water Splitting.Cryst.Growth Des.2010,10,856–861.(18)Iwase,A.;Kudo,A.Photoelectrochemical Water SplittingUsing Visible-Light-Responsive BiVO4Fine Particles Prepared in an Aqueous Acetic Acid Solution.J.Mater.Chem.2010, DOI:10.1039/c0jm00961j.(19)Watcharotone,S.;Dikin,D.A.;Stankovich,S.;Piner,R.;Jung,I.;Dommett,G.H.B.;Evmenenko,G.;Wu,S.;Chen,S.;Liu,C.;et al.Graphene-Silica Composite Thin Films as Trans-parent Conductors.Nano Lett.2007,7,1888–1892. (20)Lee,C.-G.;Park,S.;Ruoff,R.S.;Dodabalapur,A.Integrationof Reduced Graphene Oxide into Organic Field-Effect Tran-sistors as Conducting Electrodes and as a Metal Modification Layer.Appl.Phys.Lett.2009,95,0233004.(21)Kamat,P.V.Graphene-Based Nanoarchitectures.AnchoringSemiconductor and Metal Nanoparticles on a Two-Dimensional Carbon Support.J.Phys.Chem.Lett.2010,1,520–527. (22)Lambert,T.N.;Chavez,C.A.;Hernandez-Sanchez,B.;Lu,P.;Bell,N.S.;Ambrosini,A.;Friedman,T.;Boyle,T.J.;Wheeler,D.R.;Huber,D.L.Synthesis and Characterization of Titania-Graphene Nanocomposites.J.Phys.Chem.C2009,113,19812–19823.(23)Becerril,H.A.;Mao,J.;Liu,Z.;Stoltenberg,R.M.;Bao,Z.;Chen,Y.Evaluation of Solution-Processed Reduced Graphene Oxide Films as Transparent Conductors.ACS Nano2008,2, 463–470.(24)Williams,G.;Seger,B.;Kamat,P.V.TiO2-Graphene Nano-composites.UV-Assisted Photocatalytic Reduction of Graphene Oxide.ACS Nano2008,2,1487–1491.(25)Williams,G.;Kamat,P.V.Graphene-Semiconductor Nano-composites:Excited-State Interactions Between ZnO Nanoparti-cles and Graphene ngmuir2009,25,13869–13873.(26)Ng,Y.H.;Lightcap,I.V.;Goodwin,K.;Matsumura,M.;Kamat,P.V.To What Extent Do Graphene Scaffolds Improve the Photovoltaic and Photocatalytic Response of TiO2Nano-structured Films?J.Phys.Chem.Lett.2010,1,2222–2227.(27)Kim,S.R.;Parvez,M.K.;Chhowalla,M.UV-Reduction ofGraphene Oxide and Its Application as an Interfacial Layer toReduce the Back-Transport Reactions in Dye-Sensitized Solar Cells.Chem.Phys.Lett.2009,483,124–127.(28)Yang,N.;Zhai,J.;Wang,D.;Chen,Y.;Jiang,L.Two-Dimen-sional Graphene Bridges Enhanced Photoinduced Charge Transport in Dye-Sensitized Solar Cells.ACS Nano2010,4, 887–894.(29)Zhang,H.;Lv,X.J.;Li,Y.M.;Wang,Y.;Li,J.H.P25-GrapheneComposite as a High Performance Photocatalyst.ACS Nano 2010,4,380–386.(30)Hummers,W.S.;Offeman,R.E.Preparation of GraphiticOxide.J.Am.Chem.Soc.1958,80,1339–1339.(31)Iwase,A.;Kato,H.;Kudo,A.A Simple Preparation Method ofVisible-Light-Driven BiVO4Photocatalysts from Oxide Start-ing Materials(Bi2O3and V2O5)and Their Photocatalytic Activities.J.Sol.Energy Eng.2010,132,021106–021106. (32)Stankovich,S.;Dikin,D.A.;Piner,R.D.;Kohlhaas,K.A.;Kleinhammes,A.;Jia,Y.;Wu,Y.;Nguyen,S.T.;Ruoff,R.S.Synthesis of Graphene-Based Nanosheets via Chemical Reduc-tion of Exfoliated Graphite Oxide.Carbon2007,45,1558–1565.(33)Stankovich,S.;Piner,R.D.;Chen,X.;Wu,N.;Nguyen,S.T.;Ruoff,R.S.Stable Aqueous Dispersions of Graphitic Nano-platelets via the Reduction of Exfoliated Graphite Oxide in the Presence of Poly(sodium4-styrenesulfonate).J.Mater.Chem.2006,16,155–158.(34)Tokunaga,S.;Kato,H.;Kudo,A.Selective Preparation ofMonoclinic and Tetragonal BiVO4with Scheelite Structure and Their Photocatalytic Properties.Chem.Mater.2001,13, 4624–4628.(35)Treossi,E.;Melucci,M.;Liscio,A.;Gazzano,M.;Samori,P.;Palermo,V.High-Contrast Visualization of Graphene Oxide on Dye-Sensitized Glass,Quartz,and Silicon by Fluorescence Quenching.J.Am.Chem.Soc.2009,131,15576–15577. (36)A peak at26°that represents the(002)plane of graphite isnot observed for the irradiated sample.This indicates that the reduction of GO did not lead to significant restack of graphene sheet to reform bulk graphite.See:Manga,K.K.;Zhou,Y.;Yan,Y.;Loh,K.P.Multilayer Hybrid Films Consisting of Alter-nating Graphene and Titania Nanosheets with Ultrafast Elec-tron Transfer and Photoconversion Properties.Adv.Funct.Mater.2009,19,3638–3643.(37)Meyer,T.J.;Meyer,G.J.;Pfennig,B.W.;Schoonover,J.R.;Timpson,C.J.;Wall,J.F.;Kobusch,C.;Chen,X.;Peek,B.M.;Wall,C.G.;et al.Molecular-Level Electron Transfer and Excited State Assemblies on Surfaces of Metal Oxides and Glass.Inorg.Chem.1994,33,3952–3964.(38)Hagfeldt,A.;Lindstrom,H.;Sodergren,S.;Lindquist,S.-E.Photoelectrochemical Studies of Colloidal TiO2Films:The Effect of Oxygen Studied by Photocurrent Transients.J.Electroanal.Chem.1995,381,39–46.(39)T afalla,D.;Salvador,P.;Benito,R.M.Kinetic Approach to thePhotocurrent Transients in Water Photoelectrolysis at n-TiO2 Electrodes.II.Analysis of the Photocurrent-Time Depen-dence.J.Electrochem.Soc.1990,137,1810–1815.(40)Lightcap,I.V.;Kosel,T.H.;Kamat,P.V.Anchoring Semi-conductor and Metal Nanoparticles on a Two-Dimensional Catalyst Mat.Storing and Shuttling Electrons with Reduced Graphene Oxide.Nano Lett.2010,10,577–583.。
ZIF-67衍生物微纳米花状Co3O4催化剂的制备及其OER催化性能研究
Hans Journal of Chemical Engineering and Technology 化学工程与技术, 2020, 10(2), 111-118Published Online March 2020 in Hans. /journal/hjcethttps:///10.12677/hjcet.2020.102016Preparation of ZIF-67 DerivativeMicro-Nano Flower-Like Co3O4 Catalystand Its OER Catalytic PerformanceShunzheng Ren, Lijuan Feng, Shuo Yao*College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao ShandongReceived: Mar. 2nd, 2020; accepted: Mar. 16th, 2020; published: Mar. 23rd, 2020AbstractUsing ZIF-67 as a precursor, micro-nano flower-like ZIF-67(f) was obtained based on the morpho-logical evolution of ZIF-67 based on ion-assisted solvothermal conditions, and micro-nano flow-ers-like Co3O4(f) was prepared in an air atmosphere by heat treatment. Electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), Fourier infrared spectro-meter (FT-IR), and gas adsorption instrument (BET) were used to characterize the morphology and structure of the material. The electrochemical performance of the material was tested using an electrochemical workstation, and the oxygen evolution reaction (OER) performance of the cat-alyst prepared at different temperatures was discussed. The results show that the electrocatalytic performance of the prepared flower-like Co3O4(f) is greatly improved compared with commercial Co3O4 and Co3O4(r). The micro-nano flower-like Co3O4(f) material prepared by calcination at 450˚C has the most excellent electrocatalytic performance. Its overpotential at a current density of 10 mA∙cm−2 is 390 mV, and the Tafel slope is 60 mV∙dec−1.KeywordsElectrocatalysts, MOFs, Co3O4, Oxygen Evolution Reaction, ZIF-67ZIF-67衍生物微纳米花状Co3O4催化剂的制备及其OER催化性能研究任顺政，冯丽娟，姚硕*中国海洋大学化学化工学院，山东青岛*通讯作者。
原位纳米颗粒增强AA6016_基复合材料超声空化强化后微观组织及性能的变化
表面技术第52卷第8期原位纳米颗粒增强AA6016基复合材料超声空化强化后微观组织及性能的变化邹杨，刘海霞，陈杰，欧阳亚东，王雷博（江苏大学 材料科学与工程学院，江苏 镇江 212013）摘要：目的探索铝基复合材料的新型表面强化方法。
方法采用超声空化的方法对原位纳米颗粒增强AA6016铝基复合材料进行强化，使用电子天平、激光共聚焦显微镜、场发射扫描电子显微镜、显微硬度计、X射线衍射仪以及透射电镜对材料质量损失、表面形貌、残余应力、显微硬度、微观组织等方面进行系统地分析。
结果试样的质量损失和表面粗糙度随空化时间的延长而增加，在超声空化处理30 s 后，试样的表面硬度和残余压应力较原样分别提高了89.8%和57.7%，材料内部发生位错增殖，位错相互缠结，并且晶粒排列的取向差增大；当空化时间达到60 s时，显现的晶界数量增加，在晶界处出现材料剥落现象，残余应力被释放。
结论在一定的时间范围内，超声空化可以较为明显地提高材料的表面性能。
在空化泡溃灭产生的多向力作用下，铝基复合材料表面晶粒内会迅速产生大量位错，形成加工硬化层。
位错缠结和增强颗粒的钉扎作用，促使晶粒内部亚晶界的形成，最终导致晶粒细化。
关键词：铝基复合材料；超声空化强化；晶粒细化；残余应力；表面硬度中图分类号：TG178文献标识码：A 文章编号：1001-3660(2023)08-0424-09DOI：10.16490/ki.issn.1001-3660.2023.08.038Variation of Microstructure and Property of In-situNanoparticle-reinforced AA6016 Matrix Composite afterUltrasonic Cavitation StrengtheningZOU Yang, LIU Hai-xia, CHEN Jie, OUYANG Ya-dong, WANG Lei-bo(School of Materials Science and Engineering, Jiangsu University, Jiangsu Zhenjiang 212013, China)ABSTRACT: As a new composite material, in-situ nanoparticle-reinforced AA6016 aluminum matrix composite, has been developed to fulfill the requirements for the manufacturing of aerospace and automotive equipment. Although with high fatigue strength and resistance to external impact, such a material has shortcoming in terms of enduring alternating loads in收稿日期：2022-08-30；修订日期：2022-12-02Received：2022-08-30；Revised：2022-12-02基金项目：国家自然科学基金（52175410）Fund：The National Natural Science Foundation of China (52175410)作者简介：邹杨（1999—），男，硕士研究生，主要研究方向为铝基复合材料的超声空化表面改性。
最新版申请人的代表性成果包括：-一、代表性成果
黄争鸣，《西北电讯工程学院》无线电结构设备与工艺专业毕业，《华中工学院》固体力学专业硕士，《新加坡国立大学》材料工程专业博士，教育部“长江学者”，现同济大学航空航天与力学学院教授。
出版专著3本，合著4本，论文150余篇，专利16项。
联系电话：************，e-mail: ******************.cn一、代表性成果∙创建了复合材料细观力学本构与强度理论-Bridging Model，经“Failure Olympics”评比认定，是参评精度最高的细观力学理论（Comp. Sci. Tech., 2004, 64: 549-588），并且是惟一可计算纤维和基体中热残余应力的参评理论（Comp. Sci. Tech., 2004, p. 450）；∙基本解决了根据独立测试的纤维和基体原始性能参数合理预报复合材料层合板受任意载荷作用的强度这一世界性难题，使得世界著名复合材料力学专家Hashin的断言（“我确信即便最完整的单层板数据都不足以预测由这些单层板构成的层合板的破坏。
尽管在该领域已经获得长足进展，但我们依然还没有达到预测层合板破坏这一实际目标。
我本人不知道如何预测层合板的破坏，鉴于此，我也不相信任何其他人能够做到”—见Comp.Sci. Tech., 1998, 58(7): 1005）成为过去时；∙是最早提出采用同轴共纺制备芯-壳复合连续纳米纤维的技术发明人之一（发明专利号：ZL 200310108130.9），比国外学者2003年公开发表在《Advanced Materials》上的第一篇文献提早1个月，该技术曾被美国《科学》期刊刊文（Science, 2004, 304: 1917-1919）认定为静电纺丝的三大进展之一；∙给出了一般算子方程解（Hilbert第20个问题）存在性的一个充分必要条件（Nonlinear Analysis, Theory, Methods & Applications, 1989, 13: 829-832）；∙发明了“完美叶根连接与梯型块根段结构”技术（发明专利号：ZL200910197175.5），可将现有风机叶片重量同比（相同叶片外形、相同载荷工况、相同材料体系、相同加工工艺）降低15%；∙所发表的论文单篇（Comp. Sci. T ech., 2003, V ol. 63, pp. 2223–2253）最高SCI引用率已超过1800次。
YiyingWu（吴屹影）：以武（吴屹影）
Yiying Wu （吴屹影）The Ohio State University Phone: (614) 247-7810 Department of Chemistry Fax: (614)-292-1685 100 W 18th Avenue E-mail:***********************.edu Columbus, OH 43210EDUCATION:Dec. 2002 Ph.D. in Chemistry, University of California at Berkeley.Advisor: Prof. Peidong Yang.June. 1998 B.S. in chemical physics, University of Science and Technology of China.EMPLOYMENT:2005-present Assistant Professor, Chemistry Department, The Ohio StateUniversity. Interest: nanostructured functional materials.2003-2005 Postdoctoral Researcher, University of California at Santa Barbara, Department of Chemistry and Biochemistry, Advisor: Prof. Galen D.Stucky.HONORS:2010 NSF-CAREER Award2008 Cottrell Scholar Award, Research Corporation2001 MRS Graduate Student Silver Award, Boston.2001-2002Cal@Silicon Valley Fellowship, University of California at Berkeley. PROFESSIONAL MEMBERSHIPS:2001 American Chemical Society2001 Materials Research SocietyPUBLICATION LIST:u=undergraduate, g=graduate student, p=postdoc, s=senior personnel, *=corresponding author45. Y. Li g, G. Natu g, Y. Wu*. “LiFePO4/Graphene Composite as the CathodeMaterial for High-Power Lithium Ion Batteries” submitted to Nano Letters(2010).44. P. Hasin g, M. A. Alpuche-Aviles p, Y. Wu*.“Electrocatalytic activity ofgraphene multilayers towards I-/I3-: effect of preparation conditions andpolyelectrolyte modification” submitted to J. Physical Chemistry C (2010).43. G. Natu g, Y. Wu*. “Photoelectrochemical Study of the Ilmenite Polymorph ofCdSnO3 and its Photoanodic Application in Dye-Sensitized Solar Cells” J.Physical Chemistry C, accepted (2010).42. Y. Li g, P. Hasin g, Y. Wu*. “Ni x Co3-x O4 Nanowire Arrays for ElectrocatalyticOxygen Evolution”, Advanced Materials, accepted (2010).41. J. Baxter s, G. Chen s, D. Daniielson s, M. S. Dresselhaus s*, A. G. Fedorov s*, T. S.Fisher s, C. W. Jones s, E. Maginn s, U. Kortshagen s, A. Manthiram s, A. Nozik s, D.Rolison s, T. Sands s, L. Shi s*, D. Sholl s, Y. Wu s. “Nanoscale Design to Enablethe Revolution in Renewable Energy”, Energy & Environmental Science. 2(6), 559 (2009)40. Y. Li g, Y. Wu*. “Coassembly of Graphene Oxide and Nanowires for Large-Area Nanowire Alignment”, J. Am. Chem. Soc.131(16) 5851-5857 (2009).39. M. A. Alpuche-Aviles p, Y. Wu*. “Photoelectrochemical Study of the Bandstructure of Zn2SnO4Prepared by the Hydrothermal method”, J. Am. Chem.Soc.131(9) 3216-3224 (2009).38. P. Hasin g, M. A. Alpuche-Aviles p, Y. Li g, Y. Wu*. “Mesoporous Nb-dopedTiO2 as Pt Support for Counter Electrode in Dye-Sensitized Solar Cells”, J.Phys. Chem. C. 113(17) 7456-7460 (2009).37. Y. Li g, Y. Wu*. “Formation of Na0.44MnO2 nanowires via stress-inducedsplitting of birnessite nanosheets”,Nano Research, 2(1): 54-60 (2009). 36. Y. Li g, B. Tan p, Y. Wu*. "Mesoporous Co3O4 Nanowire Arrays for LithiumIon Batteries with High Capacity and Rate Capacity", Nano Letters, 8:265-270 (2008).35. Y. Li g, B. Tan p, Y. Wu*. "Ammonia-Evaporation-Induced Synthetic Methodfor Metal (Cu, Zn, Cd, Ni) Hydroxide/Oxide Nanostructures", Chem.Mater.20: 567-576 (2008).34. B. Tan p, E. Toman u, Y. Li g, Y. Wu*, "Zinc Stannate (Zn2SnO4) Dye-SensitizedSolar Cells", J. Am. Chem. Soc. 129(14), 4162 (2007).33. Y. Li g, B. Tan p, Y. Wu*, "Freestanding mesoporous quasi-single-crystallineCo3O4 nanowire arrays", J. Am. Chem. Soc. 128(44), 14258-14259 (2006)(highlighted by Nature Nanotech. (Oct. 2006)).32. B. Tan p, Y. Wu*, “Dye-Sensitized Solar Cells Based on Anatase TiO2Nanoparticle/Nanowire Composites”, J. Phys. Chem. B110: 15932-15938(2006).(Postdoc work)31. A. Thomas, M. Schierhorn, Y. Wu, G. Stucky, “Assembly of SphericalMicelles in 2D Physical Confinements and Their Replication intoMesoporous Silica Nanorods”, J. Mater. Chem. 17: 4558-4562 (2007). 30. M. Moskovits, D.H. Jeong, T. Livneh, Y.Y. Wu, G.D. Stucky, "Engineeringnanostructures for single-molecule surface-enhanced Raman spectroscopy", Isreal Journal. of Chemistry, 46: 283-291 (2006).29. Y. Zhang , J. Christofferson, A. Shakouri, D. Li, A. Majumdar, Y. Wu, R. Fan,P. Yang, “Characterization of heat transfer along Si Nanowire”, IEEETransactions on Nanotechnology, 5, 67 (2006).28.J. F. Wang, C.-K. Tsung, R. C. Hayward, Y. Wu, G. D. Stuck. “Single-crystal mesoporous silica ribbons”, Angew. Chem. Int. Ed.44: 332-336 (2005).27.Y. Wu, G. S. Cheng, K. Katsov, S. W. Sides, J. F. Wang, J. Tang, G. H.Fredrickson, M. Moskovits, G. D. Stucky, “Composite mesostructures bynano-confinement”, Nature Materials3, 816-822 (2004). (Highlighted byScience306, 943 (2004)).26.Y. Wu, T. Livneh, Y. X. Zhang, G. S. Cheng, J. F. Wang, J. Tang, M.Moskovits, G. D. Stucky, “Templat ed synthesis of highly orderedmesostructured nanowires and nanowire array”, Nano Letters 4, 2337(2004) (cover story).25.J. F. Wang, C.-K. Tsung, W. B. Hong, Y. Wu, J. Tang, G. D. Stucky,"Synthesis of mesoporous silica nanofibers with controlled porearchitectures", Chem. Mater. 16, 5169 (2004).24.J. Tang, Y. Wu, E. W. McFarland, G. D. Stucky, “Synthesis andphotocatalytic properties of highly crystalline and ordered mesoporousTiO2 thin films”, Chem. Comm. (14), 1670-1671 (2004).(Graduate work)23.A. R. Abramson, W. C. Kim, S. T. Huxtable, H. Q. Yan, Y. Wu, A. Majumdar,C.-K. Tien, P.D. Yang, "Fabrication and characterization of ananowire/polymer-based nanocomposite for a prototype thermoelectricdevice", Journal of Microelectromechanical Systems, 13(3), 505 (2004).).22.D. Y. Li, Y. Wu, R. Fan, P. D. Yang, A. Majumdar, “Thermal conductivity ofSi/SiGe longitudinal heterostructure nanowires” Appl. Phys. Lett. 83(15),3186 (2003).21.D. Y. Li, Y. Wu, P. Kim, L. Shi, N. Mingo, Y. Liu, P. D. Yang, A. Majumdar,“Thermal conductivity of individual silicon nanowires” Appl Phys. Lett.83(14), 2934 (2003).20.R. Fan, Y. Wu, D. Y. Li, M. Yue, A. Majundar, P. D. Yang, “Fabrication ofSilica Nanotube Arrays from Vertical Silicon Nanowire Templates”, J. Am.Chem. Soc.125(18), 5254-5255 (2003).19.Y. N. Xia, P. D. Yang, Y. Sun, Y. Wu, B. Mayers, B. Gates, Y. D. Yin, F. Kim,H. Yan, “One-dimensional Nanostructures: Synthesis, Characterization, andApplications”, Adv. Mater. 15(5), 353-389 (2003).18.Y. Wu, R. Fan, P. D. Yang, "Block-by-block growth of single-crystallineSi/SiGe superlattice nanowires", Nano letters, 2, 83 (2002).17.Y. Wu, H. Yan, M. Huang, B. Messer, J. Song, P. D. Yang, “Inoragnicsemiconductor nanowires: rational growth, assemblies and novel properties”, Chemistry, Euro. J., 8, 1260 (2002).16.Y. Wu, H. Yan, P. D. Yang, "Semiconductor nanowire array: potentialsubstrates for photocatalysis and photovoltaics", Topics in Catalysis, 19(2), 197 (2002).15.B. Gates, B. Mayers, Y. Wu, Y. Sun, B. Cattle, P. D. Yang, Y. N. Xia,“Synthesis and characterization of crystalline Ag2Se nanowires through atemplate-engaged reaction at room temperature”, Adv. Func. Mater. 12(10), 679-686 (2002).14.P. D. Yang, Y. Wu, R. Fan, “Inorganic semiconductor nanowires”,International Journal of Nanoscience,1(1), 1-39 (2002).13.B. Zheng, Y. Wu, P. D. Yang, J. Liu, “Synthesis of ultra-long and highly-oriented silicon oxide nanowires from alloy liquid”, Adv. Mater. 14, 122(2002).12.Y. Wu, P. D. Yang, “Direct observation of vapor-liquid-solid nanowiregrowth”, J. Am. Chem. Soc. 123, 3165 (2001).11.Y. Wu, B. Messer, P. D. Yang, "Superconducting MgB2 nanowires", Adv.Mater.13, 1487 (2001).10.Y. Wu, P. D. Yang, “Melting and welding semiconductor nanowires innanotubes”, Adv. Mater. 13, 520 (2001).9.M. Huang, S. Mao, H. Feick, H. Yan, Y. Wu, H. Kind, E. Weber, R. Russo, P.D. Yang, "Room-temperature ultraviolet nanowire nanolasers", Science,292, 1897 (2001).8.M. Huang, Y. Wu, H. Feick, N. Tran, E. Weber, P. D. Yang, “Catalytic growthof zinc oxide nanowi res through vapor transport”, Adv. Mater. 13(2), 113(2001).7.J. Song, Y. Wu, B. Messer, H. Kind, P. D. Yang, "Metal nanowire formationusing Mo3Se3- as reducing and sacrificing templates", J. Am. Chem. Soc.123, 10397 (2001).6. B. Gates, Y. Wu, Y. Yin, P. D. Yang, Y. D. Xia, “Single-crystalline nanowiresof Ag2Se can be synthesized by templating against nanowires of trigonalSe”, J. Am. Chem. Soc. 123, 11500 (2001).5.J. Song, B. Messer, Y. Wu, H. Kind P. D. Yang, "MMo3Se3 (M=Li+, Na+, Rb+,Cs+, NMe4+) nanowire formation via cation exchange in organic solution",J. Am. Chem. Soc. 123, 9714 (2001).4.Y. Li, J. Wang, Z. Deng, Y. Wu, X. Sun, S. Fan, D. Yu, P. D. Yang, “Bismuthnanotubes: a rational low-temperature synthetic route”, J. Am. Chem. Soc.123, 9904 (2001).3.Y. Wu, P. D. Yang, “Germanium/carbon core-sheath nanostructures”, Appl.Phys. Lett. 77, 43 (2000).2.Y. Wu, P. D. Yang, “Germanium nanowire growth via simple vapor transport”,Chem. Mater. 12, 605 (2000).1. B. Messer, J. H. Song, M. Huang, Y. Wu, F. Ki m, P. Yang, “Surfactantinduced mesoscopic assemblies of inorganic molecular chains”, Adv.Mater. 12, 1526 (2000).GRANTS and AW ARDS:9/07-8/10 Department of Energy, “Designing nanoparticle/nanowire composites and "nanotree" arrays as electrodes for efficient dye-sensitized solarcells”, $750,000 total9/06-9/08 Petroleum Research Fund PRF-43833, “Functional nanocrystal-nanowire composite materials: synthesis and electron transportproperties”, $35,000 total.7/08- Research Co rporation (Cottrell Scholar Award), “Searching for New Electrode Materials and Nanostructured Architectures for EfficientDye-Sensitized Solar Cells”; $100,000 total.2/10-2/15 NSF-CAREER, “Black Cobalt Oxide Nanowire Arrays: Synthesis, Properties, and Ene rgy Applications”; $575,000 totalINVITED PRESENTATIONS:Conferences/Workshops/Symposia16. FACCS conference, Lousville, KY, October 19, 2009.15. IMR Materials Week, Ohio State Unversity, August 31 – September 3, 2009.14. North American Solid State Conference, Ohio State University, June 17-20,2009.13. Central Regional Meeting of the American Chemical Society, Cleveland, May20-23, 2009.12. Materials Research Society meeting, San Francisco, April 13-17, 2009.11. Indo-US Workshop on nanoscale materials and interfaces, Purdue University,10-12 March 2009.10. Nanoparticles in Energy Applications Workshop, Argonne National Lab, Feb.23, 2009.9. ASME Heat transfer, Fluids, Energy Sustainability and Nanotechnology,Jacksonville, FL, Aug. 12, 20088. Central Regional Meeting of American Chemical Society, Columbus, OH,June 13, 20087. 35th Annual Spring Symposium, Michigan Chapter of the American VacuumSociety, Toledo, Oh, May 28, 20086. Wright Center PVIC Semi Annual meeting, Columbus, OH, April 17, 2008 5. 235th ACS National Meeting, New Orleans, LA, April 9, 20084. SPIE Optics East, Boston, MA, Sept. 9-12, 20073. Advanced Materials Workshop, Dalian, China, June 23-24, 20072. 223rd ACS national meeting, Chicago, IL, March 25-28, 20071. 41st ACS Midwest Regional Meeting, Quincy, IL, Oct. 25-27, 2006 Universities/Colleges13. IUPUI, Department of Mechanical Engineering, February 4, 2010.12. UC Davis, Department of Chemistry, January 5, 2010.11. University of Michigan, Department of Chemistry, October 30, 2009.10. Penn State University, Department of Chemistry &MRSEC, October 5, 2009.9. Purdue University, Department of Chemistry, September 16, 2009.8. The Ohio State University, ENCOMM, February 13, 20097. The Ohio State University, Department of Chemistry, January 14, 2009 (4th-year review).6. Indiana University, Department of Chemistry, April 22, 2008.5. Miami University, Department of Chemistry and Biochemistry, February 7,2008.4. Ohio University, Condensed matter and surface science seminar, May 17,2007.3. OSU, Department of Materials Science and Engineering, April 6, 2007.2. OSU, Department of Biomedical Engineering, February 2007.1. Kent State University, Department of Chemistry, September 22, 2005. PATENTS:4. “Graphene Compo sites as the Cathode Material of High-Power Lithium IonBatteries”, U.S. provisional patent, OSU1159-288A (2010).3. “Fluidic Nanotubes and Devices”, Patent No. US 7,355,216 B2 (April 8, 2008) 2. “Sacrificial Template Method of Fabricating a Nanotube”, Pa tent No.: US7,211,143 B2 (May 1, 2007).1. “Methods of fabricating nanostructures and nanowires and devices fabricatedtherefrom”, Patent N0.: WO02080280 (2002).LAB PERSONNEL:Present:Postdoctoral Associates:Dr. Dan Wang (May 2009-present)Graduate Students:Yanguang Li (5th year, Ph.D candidate); Panitat Hasin (3nd year); Gayatri Natu (3nd year); Ishika Sinha (3nd year); Tushar Kabre (2st year);。
基于纤维素纳米晶稳定的亚微米Pickering乳液制备
第21卷第4期2021年4月过程工程学报T h e Chinese Journal of Process EngineeringVol.21 No.4 Apr. 2021D O I : 10.12034/j .issn. 1009-606X.220141Preparation of submicron Pickering emulsion stabilized by cellulose nanocrystalsYanling QU 1-2, Jie WU 2*, Guanghui M A 21. School of C h e mical Engineering, University of Chinese A c a d e m y of Sciences, Beijing 100049, China2. National K e y Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese A c a d e m y of Sciences, Beijing100190, ChinaAbstract : Compared with the traditional surfactant -stabilized emulsions , Pickering emulsions stabilizedby solid particles have the advantages of strong interfacial stability , versatility , and low toxicity . A number of cases have demonstrated the potential of Pickering emulsions in biomedical applications . Submicron Pickering emulsion has a larger specific Oil phaseW a t e r pliasesqualeneC N C sPickering ennilsionssurface area and more efficient delivery efficiencythan large-sized Pickering emulsions , which is expected to further expand the advantages of Pickering emulsions in the biomedicine fields . However , the size o f Pickering emulsions isPickering emulsionsC L S M of Pickering emulsionsdetermined by many factors such as particle properties , characteristics of oil and water phase . And it is difficult to arrange the rigid particles in a limited and small oil-water interface . The above reasons increase the difficulty of preparing the submicron Pickering emulsions . The purpose of this study is to prepare stable submicron-sized Pickering emulsion by utilizing the natural polysaccharide with good biocompatibility-cellulose nanocrystals (CNCs ) as particle emulsifier , squalene as oil phase . The effects of preparation conditions such as particle concentration , oil-water ratio ,aqueous phase , ultrasonic time and frequency on size distribution and stability o f Pickering emulsions were investigated . Finally , the submicron-sized Pickering emulsion (CNCs -PE ) with good storage stability and centrifugal resistance was prepared，and the average size o f CNCs-PE was about 638.7±8.40 nm . The confocal laser scanning microscopic (CLSM ) images revealed that Pickering emulsion was formed successfully by the adsorption of CNCs on the oil-water interface . The cytotoxicity of CNCs and CNCs stabilized Pickering emulsion (CNCs -PE ) was evaluated using CCK -8 method , and it showed that there was no significant loss o f cell viability . In addition , the vaccine formulation was prepared by absorbing antigen protein -OVA . The adsorption efficiency of OVA was about 80%, and the histological micrographs of the intramuscular injection site section also showed the injection safety . It is expected to expand the applications of submicron-sized Pickering emulsion based on CNCs in biomedicine fields .Key words ： cellulose nanocrystals ; ultrasonic ; submicron Pickering emulsion ; stability o f emulsion ; biocompatibility收稿：2020-04-26，修回：2020-06~0丨，网络发表：2020~06-16，Kecfived: 2020-04-26, Revised: 2020-0^-01，Published online: 2020~06-16 基金项目：中国科学院国际合作局国际伙伴计划项目(编122m K Y S B 20180021>作者简介：屈艳玲(1993-)，女，陕西省安康市人，硕士研究生，生物化工专业，E-mail:*****************;吴颂，通讯联系人，E-mail:************.cn.引用格式：屈艳玲，吴颉，马光辉.基于纤维素纳米晶稳定的亚微米Pickering 乳液制备.过程工程学报，2021,21(4): 454~462.Q u Y L, W u J , M a G H. Preparation of submicron Pickering emulsion stabilized by cellulose nanocrystals (in Chinese). Chin. J . Process Eng.,2021,21(4): 454-^62, DOI: l0.12034/j.issn.l009-606X.220141.第4期屈艳玲等：基于纤维素纳米晶稳定的亚微米Pickering乳液制备455基于纤维素纳米晶稳定的亚微米P i c k e r i n g乳液制备屈艳玲u，吴颉2'马光辉21.中国科学院大学化学工程学院，北京1000492.中国科学院过程工程研究所生化工程国家重点实验室，北京100190摘要.•与传统表面活性剂稳定的乳液相比，固体纳米颗粒稳定的Pickering乳液具有较强的界面稳定性、多功能性、低毒性等 优势，在生物医药领域具有较大的应用潜力。
高分子纳米复合材料研究进展_高分子纳米复合材料的制备_表征和应用前景
编者按:纳米材料是当前材料科学研究的热点之一,涉及多种学科,具有极大的理论和应用价值,被誉为/21世纪最有前途的材料0,国内众多科研单位在此领域也作了大量工作,形成各自特有的研究体系。
本文(Ñ、Ò)就其中的高分子纳米复合材料,提出了作者的一些见解,供同行们共同探讨,以促进研究水平的提高,不断取得创新的成果。
高分子纳米复合材料研究进展*(I)高分子纳米复合材料的制备、表征和应用前景曾戎章明秋曾汉民(中山大学材料科学研究所国家教委聚合物复合材料及功能材料开放研究实验室广州510275)文摘综述了高分子纳米复合材料的发展研究现状,将高分子纳米复合材料的制备方法分为四大类:纳米单元与高分子直接共混(内含纳米单元的制备及其表面改性方法);在高分子基体中原位生成纳米单元;在纳米单元存在下单体分子原位聚合生成高分子及纳米单元和高分子同时生成。
介绍了高分子纳米复合材料的表征技术及其应用前景。
关键词高分子纳米复合材料,纳米单元,制备,表征,应用Progress of Polymer2Nanocomposites(I)Preparation,Characterization and Application of Polymer2NanocompositesZeng Rong Zhang Mingqiu Zeng Hanmin(Materials Science Institute of Z hongshan Uni versity,Labo ratory of Poly meric Co mpo si te&Functio nal Materials,The State Educational Commissi on of China G uangzhou510275)Abstract The progress of polymer2nanocomposites is revie wed.The preparation methods are classified into four categories:direc tly blending nano2units with polymer(including preparation and surface2modification of nano2units),in situ synthesizing nano2units in polymer matrix,in situ polymerizing in the presence of nano2units and simultaneously syn2 thesizing nano2units and polymer.The characterization and application of polymer2nanocomposites are also introduced.Key words Polymer2Nanocomposites,Nano2Unit,Preparation,Characterization,Application3高分子纳米复合材料的表征技术高分子纳米复合材料的表征技术可分为两个方面:结构表征和性能表征。
北大考研-工学院研究生导师简介-王习东
爱考机构-北大考研-工学院研究生导师简介-王习东王习东目前任职：教授、博士生导师北京大学工学院能源与资源工程系、系主任北京大学资源高效与循环利用研究中心主任北京市“固体废弃物资源化技术与管理”重点实验室主任电话：86-10-82529083电子邮箱：教育经历：北京科技大学学士、硕士瑞典皇家工学院博士研究领域：（1）资源高效与循环利用（2）能源与环境材料背景资料：多年来，主要从事资源利用与环境材料的教学、研究工作。
先后主讲了本科生、硕士生、博士生课程等16门。
在资源综合利用物理化学与材料制备物理化学等领域做出了一定成绩。
承担或完成了包括国家杰出青年科学基金课题、国家“863”课题、国家“973”课题，国家攻关课题以及国家自然科学基金重点与面上课题在内的国家与省部级课题10余项，通过鉴定6项；申报国家发明专利30多项；获得国家与省部级科学技术奖励6项。
在国内外重要学术期刊发表学术论文100余篇，其中被“SCI”收录60余篇；出版学术专著2部。
2003年晋升教授，同年批准为博士生导师；2004年获得国家杰出青年科学基金；2005年获国务院颁发的政府特殊津贴，2006年入选“新世纪百千万人才工程”国家级人选。
获得荣誉：1996年，安徽省科技进步二等奖（排名第三）1997年，国家科技进步三等奖，（排名第三）2002年，北京市科技进步二等奖（排名第二）2002年，中国冶金科学技术二等奖（排名第二）2005年，北京市自然科学二等奖（排名第一）2006年，教育部提名国家自然科学二等奖（排名第一）发表论文（部分）[1]StudiesonthePEG-AssistedHydrothermalSynthesisandGrowthMechanismofZnOMicrorodandM esoporousMicrosphereArraysontheSubstrate,CRYSTALGROWTH&DESIGN2010,10(4):1500-15 07[2]EffectsofpretreatmentofsubstratesonthepreparationoflargescaleZnOnanotubearrays,RAREMETALS2010,29(1):21-25[3]ControllableSynthesisofHigh-puritybeta-SiAlONPowder,JOURNALOFINORGANICMATERI ALS2009,24(6):1163-1167[4]PreparationandCharacterizationofTiO2NanorodArraysviaHydrothermalApproach,RAREMETA LMATERIALSANDENGINEERING,2009,38:1060-1063[5]Thermodynamicstudyandsynthesesof-SiAlONceramics,ScienceinChinaSeriesE,2009,52(11):3122-3127[6]Copperextractionfromcopperorebyelectro-reductioninmoltenCaCl2-NaCl,ELECTROCHIMICA ACTA,2009,vol.54(18):4397-4402[7]ActivityofVO1.5inCaO-SiO2-MgO-Al2O3SlagsatLowVanadiumContentsandLowOxygenPress ures,STEELRESEARCHINTERNATIONAL,2009,Vol.80(4):251-255[8]ASimpleTwo-ParameterCorrelationModelforAqueousElectrolyteSolutionsacrossaWideRangeof Temperatures,JOURNALOFCHEMICALANDENGINEERINGDATA,2009,vol.54(2):179-186 [9]ThermodynamicActivityofChromiumOxideinCaO-SiO2-MgO-Al2O3-CrOxMelts,STEELRES EARCHINTERNATIONAL,2009,vol.80(3):202-208[10]HydrothermalsynthesisofSnO2nanoflowerarraysandtheiropticalproperties,SCRIPTAMATERI ALIA,2009vol.61(3):234-236[11]TheEffectoftheTextureandtheDensityofZnOSeedLayerontheOrientationofZnONanorodArrays, JOURNALOFNANOSCIENCEANDNANOTECHNOLOGY,2009,vol.9(10):5920-5926[12]HydrothermalPreparationandCharacterizationofNanocrystallinePorousTinDioxideThinFilms,J OURNALOFNANOSCIENCEANDNANOTECHNOLOGY,2009,vol.9(10):5770-5775[13]HydrothermalsynthesisandcharacterizationofTiO2nanorodarraysonglasssubstrates,MATERIA LSRESEARCHBULLETIN,2009,vol.44(6):1232-1237[14]PreparationandpropertiesofananoTiO2/Fe3O4compositesuperparamagneticphotocatalyst,RAR EMETALS,2009,Vol.28(5):423-427[15]EstimationofFreezingPointDepression,BoilingPointElevation,andVaporizationEnthalpiesofEle ctrolyteSolutions,INDUSTRIAL&ENGINEERINGCHEMISTRYRESEARCH,2009,vol.48(4):22 29-2235[16]Template-freehydrothermalsynthesisofsingle-crystallineSnO2nanocauliflowersandtheiroptical properties,RAREMETALS,2009,Vol.28(5):449-254[17]ThermalExpansionofMagnesiumAluminumOxynitride,HIGHTEMPERATUREMATERIALS ANDPROCESSES,2008,vol.27(2):97-101[18]EffectsofPVPonthepreparationandgrowthmechanismofmonodispersedNinanoparticles,RARE METALS,2008,vol.27(6):642-647[19]ThePreparationandCharacterizationofβ-SiAlONNanostructureWhiskers,JofNanomaterials,vol.2008,ArticleID282187[20]ExtensionoftheThree-Particle-InteractionModelforElectrolyteSolutions,MaterialsandManufact uringProcesses,23:737–742,2008[21]CorrelationandPredictionofThermodynamicPropertiesofSomeComplexAqueousElectrolytesby theModifiedThree-Characteristic-ParameterCorrelationModel,J.Chem.Eng.Data,2008,53,950–958[22]CorrelationandPredictionofThermodynamicPropertiesofNonaqueousElectrolytesbytheModifie dTCPCModel,J.Chem.Eng.Data2008,53,149–159[23]Effectsofpreparingconditionsontheelectrodepositionofwell-alignedZnOnanorodarrays,Electroc himicaActa,2008,53(14):4633-4641[24]ThermodynamicevaluationandhydrothermalpreparationofKxNa-xNbO3,RareMetals,2008,27(4) :371-377[25]Anewthree-particle-interactionmodeltopredictthethermodynamicpropertiesofdifferentelectroly tes,JournalofChemicalThermodynamics,v39,n4,April,2007,p602-612[26]Density-controlledhydrothermalgrowthofwell-alignedZnOnanorodarrays,Nanotechnology,v18, n3,Jan24,2007,p035605[27]Correlationandpredictionofactivityandosmoticcoefficientsofaqueouselectrolytesat298.15Kbyth emodifiedTCPCmodel;JournalofChemicalandEngineeringData,v52,n2,2007,p538-547[28]SynthesisandcharacterizationofMgAlON-BNcomposites,InternationalJournalofMaterialsResea rch,v98,n1,January,2007,p64-71[29]SynthesisandmicrostructureofLa-dopedCeriananoparticles,J.NanoscienceandNanotechnology, V.7No.8,2007,p2883-2888[30]Phaserelationshipofcomplexmulti-componentsystemchromatecleanerproduction,ProgressinNat uralScience,V17,No.72007,p838-844[31]SynthesisandthermodynamicanalysisofNan0-La2O3,ProgressinNaturalScience,V17,No.72007, p838-844[32]Compleximpedancestudyonnano-CeO2coatingTiO2,MATERIALS&DESIGN,2006,27(6):489-493[33]Optimizationofprocessparameterspreparinghollowfibrousnickelplaquebyweb-basedANN-GAs ystem,ACTAMETALLURGICASINICA,2005,41(12):1293-1297[34]Synthesis,evaluationandcharacterizationofaluminaceramicswithelongatedgrains,CERAMICSI NTERNATIONAL,2005,31(7):953-958[35]PropertiesandstructureofAlON-VNcompositessynthesizedbyhot-pressingtechnique,RAREME TALMATERIALSANDENGINEERING,2005,JUN.34:451-454[36]PreparationandferroelectricpropertiesofPZTfibers,CeramicsInternational,2005(31):281-286[37]Kineticstudiesofoxidationofγ-AlON-TiNcompositesJournalofAlloysandCompounds,2005,387(1-2):74-81[38]StudyoftheAlON-VNcompositeceramics,KeyEngineeringMaterials,Vols280-283,2005,1139-1 142[39]ManufactureandpropertiesofAlON-TiNparticulatecomposites,KeyEngineeringMaterials,Vols2 80-283,2005,1133-1138[40]ThermodynamicstudyofK2CrO4-K2AlO2-KOH-H2OandNa2CrO4-Na2AlO2-NaOH-H2Osys tems,J.ofUniv.Sci.Tech.Beijing,2004,(6):500-504.[41]Synthesis,MicrostructuresandPropertiesOfAluminumOxynitride,MaterialsScienceandEngineer ingA,2003,245-250[42]Influenceofdifferentseedsontransformationofaluminumhydroxidesandmorphologyofaluminagr ainsbyhot-pressing,MATERIALS&DESIGN,2003,24(3):209-214[43]SynthesisofTiN/AlONCompositeCeramics,J.Mineral,MetallurgyandMaterials,2003,10(1),49-5 3[44]Modelstoestimateviscositiesofternarymetallicmeltsandtheircomparisons,ScienceinChina,2003, (3):280-289[45]OxygenSwnsitivitynano-CeO2coatingTiO2materials,SensorsandActuatorsB,2003,92(1-2):167 -170[46]SilicaPhotonicCrystalswithQuasi-fullBandGapintheVisibleRegionPreparedinEthanol,Progressi nNaturalScience,2003,(9):717-720[47]Hightoughnessaluminaceramicswithelongatedgrainsdevelopedfromseeds,ScienceinChinaSerie sE2003,46(5):527-536[48]Kineticstudiesoftheoxidationof-aluminumoxynitride,MetallurgicalandMaterialsTransactionsB, V33B,April,2002:201~207[49]Estimationofviscosityofternary-metallicmelts,MetallurgicalandMaterialsTransactionsA,V33A, No.5,2002:201~207[50]SynthesisandcharacterisationofMgAlON,Z.Metallkde(InternationalJournalofMaterialsResearc handAdvancedTechniques),V93,No.6,2002,540-544[51]KineticstudyofoxidationofMgAlONandacomparisonoftheoxidationbehaviorofAlON,MgAlON, O’SiAlON-ZrO2andBN-ZCMceramics,Z.Metallkd(InternationalJournalofMaterialsResearchandAdv ancedTechniques),V93,No.6,2002,545-553[52]Slagcorrosionofgammaaluminumoxynitride,SteelResearch,V73,No.3,2002,91~96[53]PreparationofnanostructuredCeO2CoatedTiO2,MaterialsScienceandTechnology,V18,No.3,200 2,345~348[54]Investigationofconvertorsludgepelletsforsteelmaking,J.ofUniversityofSci.andTech.Beijing,No. 3,2002,266~269[55]Experimentalstudyandoptimizationofflamegunningparametersforsteelmakingfurnaces,Naihuo Cailiao,2002,36(6):318-321。
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1. IntroductionThe production of nanostructures, nanoparticles and,generally, nanostructured materials has becomepartof everyday scientific life, whether in the researchor industrial laboratories. The embedding of nano-fillers inside polymeric systems allows us to utilizethe nano-features of (nanostructured) materials inaddition to their functionality. Such combinationsproduce ductile materials possessing switchablefunctionalities, not only for basic research, but forthe development of industrial applications.The amount of filler used plays an important role inmodifying the mechanical properties of polymers,creating new materials [1]. In functional compositesthe polymers allow the dispersed materials to betterexpress their own qualities in three-dimensionalspace. The role of polymers is to guarantee a homo-
geneous distribution for the nanofiller to exhibit abig surface area for optical applications. Duringcomposite formation it is important that the dis-persed material stays in suspension, allowing conti-nuity in the system.The macroscopic characteristics of the compositeoften reflect its own microstructure. The propertiesof composites depend on the unique filler propertiesand on the morphology and interface features of thecomposite [2]. Such composites will exhibit inter-esting electric, optical and magnetic properties. Thecharacteristics of these systems depend on the com-patibility of the constituents and the sizes of theircontact surfaces.One of the challenges of preparing nanocompositematerials is to mix compatible and homogeneousnanofillers in a polymer matrix, guaranteeing or
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Macro-micro relationship in nanostructured functionalcomposites
A. Zanotto1, A. Spinella1, G. Nasillo1, E.Caponetti1,2, A. S. Luyt3*1Centro Grandi Apparecchiature, UninetLab, Via Marini 14, 90128 Palermo Italy
2Dipartimento di Chimica “Stanislao Cannizzaro” Università degli studi di Palermo Viale delle Scienze 17, 90128
Palermo, Italy3Department of Chemistry, University of the Free State, Private Bag X13, 9866 Phuthaditjhaba, South Africa
Received 11 October 2011; accepted in revised form 2 December 2011
Abstract.This paper examines the results of the characterization of two functional composites: Poly(methyl methacrylate)(PMMA)-Ce:YAG (yttrium aluminium garnet doped with cerium) and PMMA-cobalt hexacyanoferrate (CoHCF). Thecomposites were prepared as possible emitters in the fields of lighting thermal sensors. The prepared composites were char-acterized using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, thermogravi-metric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) analyses to studythe correlation between micro and macro characteristics. We found that the molecular interactions of the two differentfillers with the matrix were localized in different sites of the polymer chains. Moreover, the composites showed anincreased thermal strength and stiffness, in particular the PMMA-Ce:YAG composite.
Keywords:nanocomposites, PMMA, yttrium aluminium garnet doped with cerium (Ce:YAG), cobalt hexacyanoferrate(CoHCF), interfacial interaction
eXPRESS Polymer Letters Vol.6, No.5 (2012) 410–416Available online at www.expresspolymlett.comDOI: 10.3144/expresspolymlett.2012.43
*Corresponding author, e-mail:LuytAS@qwa.ufs.ac.za
© BME-PTimproving the matrix performance. Poly(methylmethacrylate) (PMMA) is a commonly used ther-moplastic matrix for fibres, sheet and particles.There have been several studies on PMMA-fibrecomposites prepared by in situ polymerization [3],solution mixing [4], or melt blending [5]. The lastone is already an industrial process for fabricatingcarbon fibre-reinforced thermoplastic composites.A combination of solvent casting and melt mixingallowed to build composites with enhanced mechan-ical and electrical properties and exceptional fibre-alignment [6]. Platelets and sheets also influencethe composite's thermal and mechanical properties,in relation to the material's composition and disper-sion state within the matrix [7].Musbah et al.[8] have just discovered that nanopow-dersof phosphors Y2O3(Eu3+) embedded in a
PMMA matrix, prepared using a laboratory mixingmolder, influence almost linearly the optical anddynamic mechanical properties of the nanocompos-ites. The intensity of the luminescence emissionspectra and storage modulus, loss modulus andglass transition temperature (Tg) of the polymercomposites increased with increasing content of thenanophosphor powder.We prepared two nanostructured composites, cobalthexacyanoferrate (CoHCF) nanoparticles in PMMA,and yttrium aluminium garnet doped with cerium(Ce:YAG) nanoparticles in PMMA. CoHCF nano -particles show thermochromic behaviour, exhibit-ing a significant and non-reversible colour changearound 100°C. A new thermocromic optical sensorwith memory could be developed from this newcomposite [9]. Ce:YAG, combined with GaN bluelight emitting diodes (LED), is used for white lightsolid-state LED. In previous work it was describedhow the presence of filler (Ce:YAG) in the PMMAmatrix can cause an organization of the structureinto a lamellar shape around the particles [10]. Thisorganization could influence the macro features ofthe composites.The purpose of the present work was to study thepossible relationships between macro- and micro-features of PMMA/CoHCF and PMMA/Ce:YAGnanocomposites by means of transmission electronmicroscopy (TEM) and nuclear magnetic resonance(NMR) spectroscopy, as well as thermal and thermo-mechanical analyses. PMMA was chosen as matrixbecause of its transparency, ductility, recyclabilityand low price.2. Experimental2.1. MaterialsPotassium hexacyanoferrate(III) K3[Fe(CN)6](Sigma-Aldrich ACS reagent, 244023, !99.0%,Schnelldorf, Germany), cobalt(II) chloride hexahy-drate CoCl2"6H2O (Fluka Purum, crystallized,!98.5%, Schnelldorf, Germany) and 2,2-diethoxy-acetophenone (Sigma-Aldrich, 227102, >95%,Schnelldorf, Germany), and methyl methacrylate(MMA) (Sigma-Aldrich, M55909, #30ppm MEHQas inhibitor, 99%, Schnelldorf, Germany) were allused as received. CoHCF nanoparticles wereobtained by the reaction of potassium hexacyano-ferrate and cobalt chloride hexahydrate. 16.5mg ofK3[Fe(CN)6], dissolved into 5mL of water (0.01M)were added to 5mL of stirred water containing17.8mg of CoCl2"6H2O (0.015M) at room temper-ature. This instantly created a dark red suspension.Y(NO3)3"6H2O (Sigma-Aldrich, 237957, 99.8%,Schnelldorf, Germany), Al(NO3)3"9H2O (Sigma-