Development of novel nanomanipulators based on scanning probe microscopes

High-Speed AFM Reveals the Dynamics of Single Biomolecules at the Nanometer Scale

In this thesis, two inversion-based feedforward control approaches have been developed and implemented to high-speed large-range atomic force microscope (AFM) imaging and nanofabrication, respectively. High-speed large-range AFM imaging and nanofabrication are needed in many areas and have attracted great interests. Challenges, however, must be overcome because in high-speed largerange AFM operation, large positioning error of the AFM probe relative to the sample can be generated due to the adverse effects of the hardware. The nonlinear hysteresis and the vibrational dynamics effects of the piezotube actuator must be addressed during the high-speed lateral scanning of the AFM imaging over large imaging size. In addition, precision positioning of the AFM probe in the vertical direction is even more challenging (than the lateral scanning) because the desired trajectory (i.e., the sample topography profile) is unknown in general, and the probe positioning is also effected by and sensitive to the probe-sample interaction. Finally, in AFM multi-axis nanofabrication, additional positioning errors are induced by the large cross-axis dynamics coupling effect. The large positioning errors generated during high-speed, large-range fabrication will lead to large defects in the fabricated structures or devices. In the thesis, firstly, to compensate for the adverse effects generated during high-speed large-range AFM imaging, an integrated approach is proposed, which combines the enhanced inversion-based iterative control technique (EIIC) for lateral x-y axis scanning with a dual-stage piezoactuator for the vertical z-axis positioning. The main contribution of this integrated approach is the combination of an advanced control algorithm with an advanced hardware platform. This approach is demonstrated in experiments by imaging a large-size (50 μm) calibration sample at high speed (50 Hz scan rate). Then secondly, to achieve high-speed large-range multi-axis AFM nanofabrication, a recently developed model-less inversion-based iterative control technique (MIIC) is utilized to overcome the adverse effects involved in high-speed large-range multi-axis AFM nanofabrication. By using this advanced control technique,

This paper describes the functions underlying the creation of a collaborative framework to support robust information exchange across heterogeneous engineering domains. The application context relates to nano manipulation of particles such as proteins; the initial findings relating to distributed accomplishment of target activities in this identified context will be elaborated in this paper. In the scenario being considered, the potential project partners who possess skills and resources related to nano tube design, synthesis, manipulation plan, and simulation are identified from a service directory to form a Virtual Enterprise, with which the final target physical manipulation is formulated. In the proposed framework, the user specifications are used by various planning activities and a detailed top level plan is generated, which is represented by <NTDS, NTSS, MPS, SS>, where NTDS (Nano Tube Design Specification) is a representation of the design attributes of a carbon nano tube, NTSS (Nano Tube Synthesis Specification) is a representation that describes the synthesis of nano tube depending upon the design specification, MPS (Manipulation Plan Specification) is a representation which allows to formulate a nano manipulation plan according to user specification, and SS (Simulation Specification) is a representation that allows to generate various test cases to evaluate the nanomanipulator and the associated manipulation plan. The proposed framework is composed of an enterprise level Planning Manager (which generates a detailed top level plan from the user specification), a Design Coordinator (that identifies and evaluates the candidate design companies to find a potential design that can be used for a target nano manipulation tasks), a Synthesis/Manufacturing Coordinator (which focuses on identifying candidate partners and resources capable of manufacturing a specified nano manipulator). In the modeled context, this manipulator is a Nano tube attached to the tip of Atomic Force Microscope (AFM) probe; a Manipulation Plan Coordinator focuses on identifying candidate manipulation plan generators, and a Simulation coordinator deals with identifying candidate simulation tool vendors who provide services to evaluate nano tube and nano manipulation plan. The framework is proposed with scalability in mind so that new modules can be support a ‘plug and play’ type of integration in depending on the customer requirements.

In recent years, various electronic devices, including micromachine technology (MEMS), have been developed by nanotechnology. Since electrodeposition in an aqueous solution does not require a vacuum environment, various microfabrication and epitaxial control using electrodeposition have been investigated. Therefore, it is important to precisely and rapidly control the nanoscale interface structure during the electrodeposition process, and it is essential to elucidate the reaction process in the small region.Various methods have been studied for in-situ observation. The scanning probe microscope have given a way for atomic-scale observation, which can be applied to electrochemical nucleation and growth processes in an aqueous solution. However, the conventional scanning probe microscopes (scanning tunneling microscope: STM, atomic force microscope: AFM) require a few minutes to measure a surface, making it difficult to catch up the dynamic nucleation.A high-speed scanning probe microscope has the potential to overcome both the temporal and spatial problems. Magnussen et al. invented the video-rate STM and observed electrochemical interfacial phenomena such as metal nucleation, adatom diffusion, and molecular adsorption [1]. On the other hand, High-speed AFM (HS-AFM) was studied for biological samples [2]. Therefore, it is applicable to the imaging of soft surfaces and weakly adsorbed specimens.Taking advantage of the features of HS-AFM, we have observed Cu [3] and Zn deposition and dissolution (Fig. 1) as well as electrolytic nanobubble evolution [4]. In may talk, I would like to present dynamic behaviors of electrochemical nucleation and growth.

A hybrid imaging mode for characterization of magnetic nanomaterials has been developed, using atomic force microscopy (AFM) combined with electromagnetic sample actuation. Instead of using a coated AFM probe as a magnetic sensor; our strategy is to use a nonmagnetic probe with contact mode AFM to characterize the vibration of magnetic and superparamagnetic nanomaterials responding to the flux of an AC electromagnetic field. We refer to the hybrid imaging mode as magnetic sample modulation (MSM-AFM). An oscillating magnetic field is produced by applying an AC current to a wire coil solenoid placed under the sample stage for tuning selected parameters of driving frequency and strength of the magnetic field. When the AC field is on, the AFM probe is scanned in contact with the sample to sense periodic changes in the force and motion of vibrating nanomaterials. With MSM, responses of both the amplitude and phase signal along with spatial maps of the topography channel can be collected simultaneously. A requirement for MSM is that the samples can be free to vibrate, yet remain attached to the surface. Particle lithography was used to prepare well-defined test platforms of ring structures of magnetic or superparamagnetic nanomaterials. Capillary filling of polydimethylsiloxane (PDMS) molds was applied to generate stripes of FeNi3 nanoparticles with microscale dimensions as test platforms. The MSM-AFM imaging mode was used successfully to characterize nanomaterials of FeNi3 nanoparticles, cobalt nanoparticles, octa-substituted porphyrin nanocrystals and ionic liquid nanoGUMBOS with dimensions ranging from 1 to 200 nm. Dynamic MSM-AFM measurements can be obtained by placing the tip on a vibrating nanoparticle and sweeping the frequency or field strength. Changes in frequency spectra and vibrational amplitude can be mapped for nanoparticles of different sizes, shapes and composition. The MSM-AFM imaging mode provides a useful tool for investigating changes in size dependent magnetic properties of materials at the nanoscale. Samples of designed amyloid proteins were characterized ex situ using scanning probe microscopy. The progressive growth and fibrillization of amyloid â over extended time intervals was visualized with high resolution using AFM.

Development of fatigue testing system for in-situ observation of stainless steel 316 by HS-AFM & SEM

This article addresses the compensation for the dynamics-coupling effects in piezo-actuators used for positioning in atomic force microscopes (AFMs). Piezo-actuators are used to position the AFM probe (relative to the sample) both parallel to the sample surface (x-y-axes) and perpendicular to the sample surface (z-axis). During AFM operation, such as nanofabrication and imaging of soft biological samples, the probe-sample distance (in the z-axis) needs to be precisely controlled to maintain the probe-sample interaction at a desired value; otherwise, large variation of the probe-sample distance results in distortions of the fabricated parts (in nanofabrication) and can cause sample damage (in imaging soft biological samples). In this article, we show that dynamics-coupling from the x-y-axes (the scanning axes) to the z-axis, referred to as x-to-z dynamics-coupling, can generate significant variations in the probe-sample distance when operating AFM at high speed, i.e., when the sample is scanned at high speed. We present an inversion-based approach to compensate for these dynamics-coupling effects. Additionally, for applications where the x-y-axes movement is repetitive (as in AFM scanning operations), an iterative approach is proposed to further reduce the coupling-caused positioning errors. Convergence of the iterative approach is investigated and experimental results show that the coupling-caused errors can be reduced to the noise level using the proposed approach. Thus, the main contribution of this article is the development of an approach to substantially reduce the coupling-caused positioning errors and thereby, enable high-speed high-precision positioning of piezoscanners used in AFMs.

In nanotechnology, it is the unique properties arising from nanometre-scale structures that lead not only to their technological importance but also to a better understanding of the underlying science. Over the last twenty years, material properties at the nanoscale have been dominated by the properties of carbon in the form of the C60 molecule, single- and multi-wall carbon nanotubes, nanodiamonds, and recently graphene. During this period, research published in the journal Nanotechnology has revealed the amazing mechanical properties of such materials as well as their remarkable electronic properties with the promise of new devices. Furthermore, nanoparticles, nanotubes, nanorods, and nanowires from metals and dielectrics have been characterized for their electronic, mechanical, optical, chemical and catalytic properties.Scanning probe microscopy (SPM) has become the main characterization technique and atomic force microscopy (AFM) the most frequently used SPM. Over the past twenty years, SPM techniques that were previously experimental in nature have become routine. At the same time, investigations using AFM continue to yield impressive results that demonstrate the great potential of this powerful imaging tool, particularly in close to physiological conditions. In this special issue a collaboration of researchers in Europe report the use of AFM to provide high-resolution topographical images of individual carbon nanotubes immobilized on various biological membranes, including a nuclear membrane for the first time (Lamprecht C et al 2009 Nanotechnology 20 434001).Other SPM developments such as high-speed AFM appear to be making a transition from specialist laboratories to the mainstream, and perhaps the same may be said for non-contact AFM. Looking to the future, characterisation techniques involving SPM and spectroscopy, such as tip-enhanced Raman spectroscopy, could emerge as everyday methods. In all these advanced techniques, routinely available probes will be needed to make them mainstream methods, as was indeed the case for establishing AFM. At the same time, both transmission electron microscopy and scanning electron microscopy have undergone major developments in resolution, spectroscopic techniques, and new techniques such as tomography.It is exciting to speculate in which areas new properties of materials at the nanoscale will be discovered over the next twenty years, and how characterization methods will evolve, but it is the unimaginable and unpredictable that will bring the most dramatic changes to nanotechnology.

The silicon surface of commercial atomic force microscopy (AFM) probes loses its hydrophilicity by adsorption of airborne and package-released hydrophobic organic contaminants. Cleaning of the probes by acid piranha solution or discharge plasma removes the contaminants and renders very hydrophilic probe surfaces. Time-of-flight secondary-ion mass spectroscopy and X-ray photoelectron spectroscopy investigations showed that the native silicon oxide films on the AFM probe surfaces are completely covered by organic contaminants for the as-received AFM probes, while the cleaning methods effectively remove much of the hydrocarbons and silicon oils to reveal the underlying oxidized silicon of the probes. Cleaning procedures drastically affect the results of adhesive force measurements in water and air. Thus, cleaning of silicon surfaces of the AFM probe and sample cancelled the adhesive force in deionized water. The significant adhesive force values observed before cleaning can be attributed to formation of a bridge of hydrophobic material at the AFM tip-sample contact in water. On the other hand, cleaning of the AFM tip and sample surfaces results in a significant increase of the adhesive force in air. The presence of water soluble contaminants at the tip-sample contact lowers the capillary pressure in the water bridge formed by capillary condensation at the AFM tip-sample contact, and this consequently lowers the adhesive force.

INTRODUCTION Background History of Microscopy SCANNING PROBE MICROSCOPES (SPMS) Scanning Tunneling Microscope Electron Tunneling Atomic Force Microscope (AFM) Modes of Operation of AFM Simultaneous AFM and Scanning Near-Field Fluorescence (SNOM and SNOM-AFM) Friction Force Microscopy (FFM) STM and AFM Studies under Fluids Sample Preparation Procedures for STM and AFM Calibration and Image Analysis of STM and AFM Comparative Studies of Diverse Molecules by STM and AFM LIPID-LIKE MOLECULES ON SOLIDS AND SAMS Collapsed Lipid Monolayers (Self-Assembly) Domain Patterns in Monomolecular Film Assemblies Mixed Lipid Molecule Assemblies Holes in LB Films of Self-Assembly Monolayers Visualization of Vesicles by AFM LB Films of Liquid Crystals STM and AFM Studies of Diverse Molecules on Solids STM Studies on the Effect of Functional Group BIOPOLYMERS AND SYNTHETIC POLYMERS STRUCTURES BY STM AND AFM DNA Structures by STM and AFM SPM Studies of Three-Dimensional Protein Structures Protein Adsorption Studies by AFM Biological Macromolecular Structures Synthetic Polymers Studies by SPMs Mixed Monolayers of Macromolecules and Lipids Diverse Macromolecular Properties as Studied by SPMs Monolayers of Synthetic Polyamino Acids Biopolymer SAM Structures at Interfaces by STM and AFM CRYSTAL STRUCTURES BY STM AND AFM Crystal Structures of Small Molecules Surface Adsorption Studies by SPMs Macromolecule Crystals by STM and AFM STUDIES OF SOLID SURFACES BY SPMS Wetting Properties of Solid Surfaces AFM Analyses of Surface Acid-Base Properties Measurement of Attractive and Repulsive Forces by Atomic Force Microscope (AFM) DIVERSE APPLICATIONS OF SPMS (STM AND AFM, ETC.) AND NANOTECHNOLOGY STM and AFM in Organic Chemistry Semiconductor Study by SPM STM and AFM in Inorganic Chemistry Nanolithography and Nanomachining Qualitative and Quantitative Analyses at Nanoscale Application of SPMs under Dynamic Conditions Application of AFM to Immunodiagnostic Systems Applications of STM and AFM in Industry SPM Studies of Nanoscale Reactors Nanoscale Evaluation of Surface Roughness by SPMs Application of STM and AFM in Pollution Control Friction Force Microscope (FFM) Time-Resolved Analyses by STM REFERENCES

In this review, we discuss the progress in the investigation of macromolecular crystals obtained through the use of atomic force microscopy (AFM), a powerful tool for imaging surfaces and specimens at high resolution. AFM enables the visualization of soft samples at the nanoscale and can provide precise visual details over a wide size range, from the molecular level up to hundreds of micrometers. The nonperturbative nature, the ability to scan in a liquid environment, and the lack of need for freezing, fixing, or staining make AFM a well-suited tool for studying fragile samples such as macromolecular crystals. Starting from the first morphological investigations revealing the surface morphology of protein crystals, this review discusses the achievements of AFM in understanding the crystal growth processes, both at the micro- and nanoscale. The capability of AFM to investigate the sample structure at the single molecular level is analyzed considering in-depth the structure of S-layers. Lastly, high-speed atomic force microscopy (HS-AFM) is discussed as the evolution to overcome the limitations of low imaging speed, allowing for the observation of molecular dynamics and weakly adsorbed, diffusing molecules. HS-AFM has provided intuitive views and directly visualized phenomena that were previously described indirectly, answering questions that were challenging to address using other characterization methods.

A hierarchic set of gradually complicated models is suggested. The models describe the contact condition of the mechanical interaction between the atomic force microscope (AFM) probe and the investigated surface while allowing for various factors. A variant of the AFM probe-surface mechanical interaction model is developed which takes into account the simultaneous effect of the probe geometry and the elastic deformations of the AFM cantilever that take place when there is a small or moderate curvature of surfaces under study. A variant of the model of interaction between the AFM probe and the surface of the investigated specimen is discussed, taking into consideration the simultaneous effect of the probe geometry and elastic deformations of the AFM cantilever and the probe contact with the surface under study within the framework of Derjaguin-Muller-Toropov model. Algorithms to determine the AFM probe position are created to optimize computations.

Friction plays a crucial role in both natural phenomena, from the flow of blood cells to earthquakes, and technological applications, from car engines to wind turbines. One of the most fundamental aspects of tribology is friction anisotropy, that is, the dependence of the friction force vector on the direction of sliding. Even when two identical surfaces slide against each other, differences in sliding direction can lead to significantly different friction forces. While atomistic and semi-empirical models provide a good understanding of friction and friction anisotropy at the molecular and macroscale levels, a comprehensive understanding at the nano- and microscale remains elusive. Unravelling the mechanisms of friction anisotropy at these intermediate length scales is crucial for bridging the gap between the current atomistic and macroscale models, as well as for advancing technological applications, such as nano-/micro-electromechanical systems (NEMS/MEMS). One experimental technique which has significantly contributed to the study of nano- and micro-scale friction anisotropy is scanning probe microscopy, particularly the form of atomic force microscopy (AFM). AFM enables investigations at the nanometre-scale resolution, providing at equilibrium topographical, physical, and chemical information of interfaces with atomic precision. AFM can also measure friction forces with pN-level sensitivity while operating in vacuum, air or fluid environments. The versatility of AFM and its applicability to both soft and hard materials have made it an indispensable tool for understanding the nano- and microscale mechanisms of friction. In this review, we examine the contributions of AFM-based techniques to the study of friction anisotropy. First, we summarise key AFM findings on friction anisotropy arising from the periodic corrugation of atomically flat crystals, quasicrystals, 2D materials and organic materials. In the second part, we explore friction anisotropy mechanisms influenced by the presence of solid or fluid adsorbates, such as polymers or liquid lubricants. By synthesising insights from the last 30 years of research, our review contributes to a deeper understanding of friction anisotropy, identifying common mechanisms across the diverse systems. This knowledge will not only refine theoretical models but also drive technological advancements, in a wide range of applications from biomedical devices and 3D printing to engines and advanced lubricant formulations.

Reconstruction of atomic force microscopy image using compressed sensing

Carbon nanotubes (CNTs) can be used as atomic force microscope (AFM) probes due to their robust mechanical properties, high aspect ratio and small diameter. In this study, a model of CNTs clamped in an elastic medium is proposed as CNT AFM probes. The buckling instability of the CNT probe clamped in elastic medium is analyzed based on the nonlocal Euler–Bernoulli beam model and the Whitney–Riley model. The clamped length of CNTs, and the stiffness of elastic medium affect largely on the stability of CNT AFM probe, especially at high buckling mode. The result shows that the buckling stability of the CNT AFM probe can be largely enhanced by increasing the stiffness of elastic medium. Moreover, the nonlocal effects of buckling instability are investigated and found to be lager for high buckling mode. The theoretical investigation on the buckling stability would give a useful reference for designing CNT as AFM probes.