电化学原子力显微镜的应用

评述了电化学原子力显微镜的原理和技术及其在现场电化学和电分析化学领域的应用,如观察电镀、腐蚀和防腐的过程,电化学沉积膜的形成和特点,测定两表面间的静电力等,指出其存在的一些缺陷,并对经过改造后的电化学原子力显微镜进行了综述。     

In-situ investigations on the SILAR-growth of ZnS films as studied by tapping mode atomic force microscopy

Tapping mode atomic force microscopy (TM-AFM) has been successfully used for in-situ imaging of the deposition of ZnS films with the successive ionic layer adsorption and reaction (SILAR) method. The films were deposited in-situ using the commercial TM-AFM liquid cell as a flow-through reactor. The potential of TM-AFM has been used to study the growth of ZnS on different substrates up to 50 SILAR cycles. Reactants and rinsing water were alternately exchanged in the cell by a computer controlled valve system. In comparison to earlier work performed with the conventional AFM operated in contact mode, imaging artefacts introduced by lateral shear forces can be largely eliminated with TM-AFM. On glass the roughness is observed to decrease initially until typical island formation takes place at a larger number of deposition cycles. On mica island formation can be observed right from the beginning of the process and the roughness increases with increasing number of deposition cycles.     

聚甲基丙烯酸甲酯/苯乙烯-丙烯腈无规共聚物薄膜表面原位原子力显微镜相图

采用原位原子力显微镜在线跟踪方法,研究了聚甲基丙烯酸甲酯/苯乙烯 丙烯腈无规共聚物共混体系表面相分离行为,得到了具有下临界共溶温度（临界温度约为175 ℃）原位相图。 与文献报道的用离位方法所得结果的主要差别是原位的临界相分离温度稍有提高,以及离位结果中存在的组成对称性。 这些差别主要来源于离位和原位实验方法上的差别,薄膜厚度减小导致的相容性,热力学历史的变化以及基底效应的加剧。     

锂电池原位与非原位表征技术研究

锂电池的电化学性能与电子及离子在体相与界面的输运、反应、储存行为有关. 从原子尺度到宏观尺度,对电池材料在平衡态与非平衡态过程的电子结构、晶体结构、微观形貌、化学组成、物理性质的演化研究对于理解锂离子电池中各类构效关系至关重要,这需要综合多种原位与非原位表征技术. 目前,基础研究处于前沿的发达国家在这些方面取得了卓有成效的进展. 本文简介了中国科学院物理研究所近年来通过国内外合作,采用原位X射线衍射（in-situ XRD）、原位X射线吸收谱（in-situ XAS）、准原位/原位扫描电镜（quasi/in-situ SEM）、球差校正扫描透射电镜（HAADF/ABF-STEM）、扫描力曲线（Force-Curve）、中子衍射（Neutron Diffraction）、热重-差示扫描量热-质谱联用（TG-DSC-MS）、表面增强拉曼（SERS）等技术研究锂离子电池电极材料结构演化方面的进展,并对未来锂离子电池研究中先进表征技术的发展进行了简要的探讨.     

Improving the interfacial property of carbon fibre/epoxy resin composites by grafting amine-capped cross-linked poly-itaconic acid

To improve the interfacial properties of carbon fibre-reinforced polymer composites, a surface treatment was used to cap cross-linked poly-itaconic acid onto carbon fibres via in-situ polymerization after itaconic acid grafting. The chemical composition of the modified carbon fiber (CF) surface was characterized by X-ray photoelectron spectral and Fourier-transform infrared spectroscopy. Scanning electron microscopy and atomic force microscopy images showed that the poly-itaconic acid protective sheath was uniformly capped onto the CF surface and that the surface roughness was obviously enhanced. Chemical bonds also played a key role in the interfacial enhancement. The results showed that the interfacial shear strength of the composites with poly-itaconic acid on the carbon fibres (72.2 MPa) was significantly increased by 89.5% compared with that of the composites with pristine CF (38.1 MPa). Moreover, the poly-itaconic acid sheath promoted a slight increase in mono-fibre tensile strength. In addition, the interfacial mechanisms were also discussed. Meanwhile, the mechanical property of the functionalized CF/epoxy resin composites was also significantly improved.     

Atomic force microscopy of extended-chain crystals of polyethylene

Extended-chain crystals of polyethylene grown at elevated pressure and temperature were analyzed for the first time by atomic force microscopy. It was possible to compare the typical fracture surface striation features with those obtained earlier by electron microscopy. High resolution atomic force microscopy on flat surfaces enabled the recording of an atomic scale regularity that could not be fully indentified. © 1993 John Wiley & Sons, Inc.     

Nanocharacterization techniques for investigating the durability of wood coatings

Nanocharacterization techniques such as nanoindentation and atomic force microscopy were used to investigate the exterior durability of waterborne coatings improved with inorganic nanosized UV-absorbers. Nanocomposite coatings for exterior uses of wood were formulated with different type of nanoparticles and their performance was evaluated trough artificial aging. Nanoindentation in continuous stiffness mode was used to demonstrate the changes of hardness and Young’s modulus of the coatings after accelerated weathering. The degradation mechanism of the surface coatings was investigated with atomic force microscopy that has provided valuable information on the morphological and microstructural changes of the surface coatings with the artificial aging. Additionally, the glass transition temperature and optical appearance changes were reported. The results obtained have shown that the nanoindentation technique in conjunction with atomic force microscopy can be satisfactorily used for durability investigation and service life prediction of nanocomposite coatings for wood.     

Preparation of Silicon Thin Films of Different Phase Composition from Monochlorosilane as a Precursor by RF Capacitive Plasma Discharge

Monochlorosilane/argon/hydrogen (SiH₃Cl-Ar-H₂) mixture of different ratios was investigated from the point of PECVD application. RF capacitive plasma discharge of 40.68 MHz frequency was used. The process of deposition was studied by optical emission spectroscopy. The silicon thin films of different phase composition were obtained. The thin films were characterized by Raman-spectroscopy, atomic force microscopy, and secondary ion mass spectrometry. The exhaust gas mixture was analyzed by IR-spectroscopy in outlet of the reactor during PECVD process. The chemical mechanism for the deposition process was also proposed.     

In-situ AFM studies of the phase-transition behavior of single thermoresponsive hydrogel particles

The volume phase transition (VPT) behavior of individual thermally responsive poly(N-isopropylacrylamide-co-acrylic acid) (pNIPAm-co-AAc) hydrogel microparticles was studied by in-situ dynamic mode atomic force microscopy (AFM) and force spectroscopy during heating and cooling cycles. Hydrogel samples were prepared by electrostatic immobilization of microparticles to amine-modified gold surfaces. The AFM studies of particle deswelling were performed by varying the force applied on the particles during imaging as a function of the geometry and material of the AFM probe. Aluminum-coated silicon cantilevers were found to influence substantially the behavior of the particles during the VPT, leading to a significant shape change. Low force impact magnetic excitation of the AFM probe (MAC mode) during dynamic mode measurements resulted in an undisturbed deswelling behavior enabling observation of the expected volume changes of the particles without significant tip-sample interaction. Hence, MAC-mode AFM was determined to be the most suitable technique for in-situ AFM studies on volume and shape changes at single hydrogel particles during VPT. Elasticity measurements performed at single particles at temperatures below and above the VPT revealed a 15-fold increase in the Young's modulus after passing the VPT, indicating the transition from a soft, swollen network to a stiffer, deswollen state.     

Synthesis and characterization of heat-stabilized albumin magnetic microspheres

Human serum albumin magnetic microspheres containing 30% iron oxide particles were synthesized by a heat-stabilization process. The average diameter, the size distribution and the morphology were characterized by scanning electron microscopy, atomic force microscopy and transmission electron microscopy. The distribution of the iron oxide nanoparticles within the microspheres was confirmed by the contrast obtained in the morphology by backscattered electron imaging in scanning electron microscopy. Energy-dispersive X-ray spectroscopy showed the presence of iron in the microspheres. The cabbage like surface structure in some of the microspheres obtained in scanning electron microscopy can be better understood by atomic force microscopy. This peculiar surface structure in the microsphere may be due to the cross-linking in the protein molecule by heat. The amount of iron oxide in the microsphere was analyzed by atomic absorption spectroscopy. The magnetic properties of the particles were measured in a superconducting quantum interference device magnetometer. Received: 12 September 2000 Accepted: 5 February 2001     

Influence of increasing zinc contents in brass in the early stages of corrosion investigated by in-situ TM-AFM and SIMS

In-situ tapping mode atomic force microscopy (TM-AFM), a powerful, high-resolution imaging technique for determining the structure of surfaces and ex-situ secondary ion mass spectroscopy (SIMS), a multielement, high-depth-resolution method, were used to examine the influence of increasing zinc contents in brass in the early stages of corrosion. Four different samples (pure Cu, pure Zn, Cu/Zn=90/10 wt% and Cu/Zn=70/30 wt%) were studied in order to determine their chemical behaviour under various atmospheric conditions. The in-situ TM-AFM investigations were carried out in synthetic air with 60% relative humidity (RH) and 80% RH with 250 ppb SO(2). The samples for the ex-situ SIMS experiments were weathered over a period of 60 h in 80% RH and 250 ppb SO(2). The in-situ TM-AFM investigations have shown that an increasing Zn content in brass increases the corrosion rate.     

聚(苯乙烯-co-甲基丙烯酸)胶体晶体原位反转制备孔阵列研究

利用甲苯浸泡法,将聚(苯乙烯-co-甲基丙烯酸)(P(Sc-o-MAA))胶体晶体转变成孔阵列,利用扫描电镜和原子力显微镜详细研究了胶体球在向孔转变过程中结构的变化细节,同时利用表面元素分析法检测其反转前后元素含量的变化.结果表明,在选择性溶剂作用下,胶体球经历了溶胀—粘连—破裂—溶解—成孔—扩张等一系列变化,处于内核的聚苯乙烯被溶出胶体球后不仅填充到球与球之间的空隙中而且扩散到了溶剂中,而胶体球表面富集的聚甲基丙烯酸链段与溶出的聚苯乙烯混合物则主要对孔结构起固定和支撑作用,但长时间的甲苯浸泡最终会破坏孔的结构和阵列的完整性.     

Directly observed covalent coupling of quantum dots to single-wall carbon nanotubes

Carboxylate chemistry is used to covalently couple metal nanoparticles to defect sites in controllably oxidized single-walled carbon nanotube termini and side-walls, and this process monitored by atomic force microscopy.     

Size-Selective Organization of Silica and Silica-Like Particles on Solid Interfaces through Layer-by-Layer Assembly

Employing a layer-by-layer assembly technique, we created three-dimensional architectures of silica and silica-like particles on solid interfaces. Atomic force and scanning electron microscopy confirmed a size-selection effect for assembling a mixture of two kinds of monodispersed silica particles prepared through the sol-gel process. Size-selective assembly was also applied for layer-by-layer organization of Cerasomes, which are organic-inorganic vesicular hybrids with a silica-like structure on the lipid bilayer surface. This study obtained an alternating layer-by-layer assembly of Cerasomes with a relatively uniform size on solid interfaces from polydispersed aqueous colloids of a surface-modified cationic Cerasome with an unmodified anionic Cerasome or an anionic poly(vinyl sulfate). Quartz crystal microbalance measurements and atomic force microscopy were used to evaluate this assembly process.     

Preparation of End Grafted Polyacrylonitrile Brushes through Surface Confined Radical Chain Transfer Reaction

End grafted polyacrylonitrile (PAN) brush was prepared through surface initiated polymerization via the chain transfer process.The thiol-terminated monolayer and PAN brushes were characterized by FTIR,X-ray photoelectron spectroscopy(XPS),atomic force microscopy (AFM),ellipsometry and contact angle measurements etc.It is demonstrated that radical chain transfer reaction and surface initiated precipitate polymerization can used to prepare end-grafted polymer brushes.     

电化学控制产生纳米氧气气泡及其对电化学聚合吡咯形貌的影响

利用原位电化学原子力显微镜(in-situ EC-AFM)研究了纳米氧气气泡在高定向热解石墨(HOPG)表面的电化学控制产生与生长. AFM原位图像表明电化学产生的氧气在HOPG表面形成了纳米气泡, 并且纳米气泡的产生与生长可以通过改变外加电压和反应时间来进行控制. 随后, 研究了电化学产生的纳米氧气气泡对于在HOPG表面电化学聚合吡咯反应的影响, 结果表明伴随聚合反应过程产生的纳米氧气气泡使得生成的聚吡咯膜表面形成了气泡状的缺陷.     

Local surface charge dissipation studied using force spectroscopy method of atomic force microscopy

We propose herein a method to study local surface charge dissipation in dielectric films using force spectroscopy technique of atomic force microscopy. By using a normalization procedure and considering an analytical expression of the tip‐sample interaction force, we could estimate the characteristic time decay of the dissipation process. This approach is completely independent of the atomic force microscopy tip geometry and considerably reduces the amount of experimental data needed for the calculation compared with other techniques. The feasibility of the method was demonstrated in a freshly cleaved mica surface, in which the local charge dissipation after cleavage followed approximately a first‐order exponential law with the characteristic time decay of approximately 7–8 min at 30% relative humidity (RH) and 2–3.5 min at 48% RH. Copyright © 2015 John Wiley & Sons, Ltd.     

Probing structural changes of spin-coated polystyrene film after swelling and precipitation by synchrotron GIUSAXS and AFM

Polystyrene film of about 50 nm in thickness on silicon wafer was obtained by spin-coating in tetrahydrofuran solution. The film exhibits a rough surface as shown by atomic force microscopy images and ellipsometry data. Furthermore, such surface roughness produced a characteristic lateral correlation peak in an “out-ofplane” scan in the synchrotron grazing incidence ultra-small angle X-ray scattering pattern. The film was treated with liquids of solvent and non-solvent sequentially, resulting in a process of swelling and precipitation of the polystyrene film. Such a solvent/non-solvent treatment completely changed the original surface structure of the film. Aggregates of polystyrene of different sizes were observed both in atomic force microscopy and synchrotron grazing incidence ultra-small angle X-ray scattering measurements. The results demonstrate that synchrotron grazing incidence ultra-small angle X-ray scattering is a unique means to investigate large area micro-structural features of thin films supported on smooth surfaces.     

肿瘤细胞的原子力显微术成像及表征研究

本文简单介绍了原子力显微镜的发展史,以及原子力显微镜的工作原理、工作模式、活细胞在生理状态下的成像方式等,特别介绍了生物型原子力显微镜、高速原子力显微镜在生物学领域的研究及应用。原子力显微镜在扫描速度、扫描范围、扫描精度方面的不断改进将为肿瘤细胞学研究提供源源不断的动力。本文着重阐述了原子力显微术在肿瘤领域的研究进展,包括原子力显微镜在肿瘤细胞形貌学特性、硬度、粘弹性方面的研究现状,并对原子力显微镜在肿瘤诊断及抗肿瘤药物研发方面的应用前景进行了展望。     

Multilayer assembly and patterning of poly(p-phenylenevinylene)s via covalent coupling reactions

Poly(p-phenylenevinylene)s with amines and pentafluorophenyl esters on side chains were synthesized and assembled on solid substrates by sequential layer-by-layer (LBL) deposition. This approach enables the creation of robust multilayer thin films via in-situ covalent coupling reactions between successive layers. The buildup of the multilayers was followed by UV/vis absorption spectroscopy and ellipsometry. The observed complex assembly behavior suggests that both covalent and hydrogen-bonding interactions are involved in the formation of multilayer films. The organized structure and surface morphology of resultant multilayers were investigated by reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. This covalent LBL method was further applied to generate conjugated polymer micropatterns using microstamped self-assembled monolayers as templates.