Atomic Force Microscope (AFM)

The defined formation and expansion of droplets are essential operations for droplet-based screening assays. The volumetric expansion of droplets causes a dilution of the ingredients. Dilution is required for the generation of concentration graduation which is mandatory for many different assay protocols. Here, we describe the design of a microfluidic operation unit based on a bypassed chamber and its operation modes. The different operation modes enable the defined formation of sub-µL droplets on the one hand and the expansion of low nL to sub-µL droplets by controlled coalescence on the other. In this way the chamber acts as fluidic interface between two fluidic network parts dimensioned for different droplet volumes. Hence, channel confined droplets of about 30-40 nL from the first network part were expanded to cannel confined droplets of about 500 to about 2500 nL in the second network part. Four different operation modes were realized: (a) flow rate independent droplet formation in a self-controlled way caused by the bypassed chamber design, (b) single droplet expansion mode, (c) multiple droplet expansion mode, and (d) multiple droplet coalescence mode. The last mode was used for the automated coalescence of 12 droplets of about 40 nL volume to produce a highly ordered output sequence with individual droplet volumes of about 500 nL volume. The experimental investigation confirmed a high tolerance of the developed chamber against the variation of key parameters of the dispersed-phase like salt content, pH value and fluid viscosity. The presented fluidic chamber provides a solution for the problem of bridging different droplet volumes in a fluidic network.

I. INTRODUCIÓN Sabemos que el controlador es una parte fundamental para el funcionamiento de un microscopio de fuerza atómica, que le permite lograr durante el escaneo una resolución del orden de los nanómetros llegando hasta el nivel at´omico, de ahí la relevancia de esta herramienta. El microscopio de fuerza atómica es un instrumento poderoso y versátil que puede analizar cualquier tipo de material sin mayor preparación de

We analyze transient current data during the formation of titanium oxide nanodots by AFM-tip-induced anodic oxidation with the aim of getting further understanding of local oxidation kinetics. The measured current waveforms show a transition between two distinct regimes, in agreement to what was previously known of the growth process, and their behavior is discussed with respect to the oxide growth rate and to the formation of the space charge. Furthermore, it is shown how the knowledge of the duration of the first transient regime can be exploited to optimize the application of pulsed bias voltages to obtain a substantial improvement in aspect ratio of growing oxides.

We investigate the effect of different voltage waveforms on the growth of titanium oxide nanodots using Atomic Force Microscope (AFM) nanolithography. The resulting oxide features are compared by taking into account the current data detected during oxidation under the application of constant and linear ramp voltages. The experimental analysis of current waveforms during oxidation upon a constant bias voltage gives quantitative criteria to reduce space charge effects. The use of ramp voltages gives higher flexibility on the control of volume and aspect ratio of oxide features by varying the duty cycle.

In this work, we investigate the chemical conditions for inducing a self-organized growth of 2D and 1D structures of gold nanoparticles (NPs), 50 nm diameter tri-sodium citrate stabilized, assembled onto chemically modified glass substrates through 3-Aminopropyltriethatoxysilane. The aggregation process of the nanoparticles on the silanised surface has been controlled by optimizing the concentration limit, immersion time and annealing process of NPs. A recipe to obtain the appropriate electrical charge conditions necessary for inducing the dimensionality transition of the organized nanostructures from 2D to 1D has been determined through the comparison between two deposition routes employing different polar solvents (water and ethanol). The self-organized growth of gold NPs into structures of different dimensionality has been extensively investigated by Atomic Force Microscopy and discussed.

In this study, enhanced oil recovery (EOR) techniques—namely low salinity and nanofluid EOR—are probed at the nanometer-scale using an atomic force microscope (AFM). Mica substrates were used as model clay-rich rocks while AFM tips were coated to present alkyl (-CH3), aromatic (-C6H5) and carboxylic acid (-COOH) functional groups, to simulate oil media. We prepared brine formulations to test brine dilution and cation bridging effects while selected concentrations (0 to 1 wt%) of hydrophilic SiO2 nanoparticles dispersed in 1 wt% NaCl were used as nanofluids. Samples were immersed in fluid cells and chemical force mapping was used to measure the adhesion force between polar/non-polar moieties to substrates. Adhesion work was evaluated based on force-displacement curves and compared with theories. Results from AFM studies indicate that low salinity waters and nanoparticle dispersions promote nanoscale wettability alteration by significantly reducing three-phase adhesion force and the r...

Nanochemistry and nanocatalysis are dynamic fields intersecting chemistry and nanotechnology, capturing attention from researchers and industries. This paper presents current trends and future prospects in these domains. It explores fundamental principles, synthesizing and manipulating nanomaterials with unique properties. It delves into nanocatalysis strategies using nanomaterials as efficient catalysts, offering high selectivity and activity. Recent advances in designing catalytic nanomaterials, including noble metals, metal oxides, and carbon-based nanomaterials, are highlighted. Applications in energy conversion, environmental remediation, and pharmaceutical synthesis are discussed. Computational techniques and AI accelerate nanocatalysis research. The paper emphasizes the role of nanocatalysis in sustainable and eco-friendly chemical transformations. Challenges and opportunities call for interdisciplinary collaboration and responsible development for harnessing nanotechnology's potential in addressing global needs.

Diamondoids are cage-like hydrocarbon materials with unique characteristics such as low dielectric constants, negative electron affinity, large steric bulk, and electron-donating ability. They are widely used for advanced functional materials in nanocomposite science. Surface modification of diamondoids also produces functional derivatives that broaden its applications. This article provides a concise review of the fundamentals of diamondoids, including their origin and functionalization, electronic structure, optical properties, and vibrational characteristics. The recent advances of diamondoids and their derivatives in applications, such as nanocomposites and thin film coatings, are presented. The fabrication of diamondoid-based nanostructured devices, including electron emitters, catalyst sensors, and light-emitting diodes, are also reviewed. Finally, the future developments of this unique class of hydrocarbon materials in producing a novel nanostructure system using advanced nan...

The localized corrosion of AA2024-T3, and the behavior of intermetallic particles in particular, were studied using different capabilities of the atomic force microscope (AFM). The role of intermetallic particles in determining the locations and rates of localized corrosion was determined using scanning Kelvin probe force microscopy in air after exposure to chloride solutions. Al-Cu-Mg particles, which have a noble Volta potential in air because of an altered surface film, are actively dissolved in chloride solution after a certain induction time. Al-Cu-(Fe, Mn) particles are heterogeneous in nature and exhibit nonuniform dissolution in chloride solution as well as trenching of the matrix around the particles. Light scratching of the surface by rastering with the AFM tip in contact mode in chloride solution results in accelerated dissolution of both pure Al and alloy 2024-T3. The abrasion associated with contact AFM in situ resulted in the immediate dissolution of the Al-Cu-Mg particles because of a destabilization of the surface film.

Trans-endodontic implants are an artificial extension through root apex anchored in periradicular bone tissue. The aim is to improve the crown-root ratio and to provide stability to dental organ present. Zirconium oxide (ZrO2) is a material of great technological importance, having good natural color, high strength, high toughness, high chemical stability, does not suffer any corrosion, chemical and microbial resistance and excellent esthetic properties.  Objective: The aim of this study was to evaluate chemical and microscopy of surface conditions of ZrO2 trans-endodontic implant. Materials and Methods: A blocks of ZrO2 were manufactured for produce trans-endodontic implants and divided in two groups: monoclinic and tetragonal phase. They were evaluated using Scanning Electroning Microscope (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and Atomic Force Microscope (AFM) and Vickers Micro hardness. Results: The Monoclinic phase through AFM analysis showed roughness Ra = 0.320μm,...

Thermal energy storage (TES) is one method to accumulate thermal energy. In TES, latent heat storage using phase change materials (PCM) has attracted a lot of interest, recently. Phase change slurries (PCS) consist on a carrier fluid binary system composed of water as the continuous phase and microencapsulated PCM as the dispersed phase. In this paper, two PCS to be used for TES in buildings were studied: Micronal ® DS 5007 X, from BASF company, and PCS28, a laboratory made sample. Both samples were characterized using particle size distribution and scanning electron microscopy, to observe the regular spherical microcapsules, the surface morphology, and the wall shell thickness of the microcapsules. Atomic force microscopy was used to analyze the force needed to break the PCS microcapsules, a critical parameter when the PCS are to be used in active pumpable systems, and also to evaluate the effective Young's modulus. Both samples were studied with the microcapsules broken and unbroken. The physicochemical and thermal properties were reported in a previous paper, and it can be concluded that both are proper candidates to be used in TES building heating and cooling applications, but the acrylic shell microcapsules present better breakage resistance to be used in active systems.

to the nanoscale. Their evolution may be traced to three exciting happenings that took place in a short span from the early to mid-1980s with the award of Nobel prizes to each of them. These were: (i) the discovery quantum Hall effect in a two-dimensional electron gas; (ii) the invention of scanning tunnelling microscopy (STM); and (iii) the discovery of fullerene as the new form of carbon. The latter two, within a few years, further led to the remarkable invention of the atomic force microscope (AFM) and, in the early 1990s the extraordinary discovery of carbon nanotubes (CNT), which soon provided the launch pad for the present-day nanotechnology. The STM and AFM have emerged as the most powerful tools to examine, control and manipulate matter at the atomic, molecular and macromolecular scales and these functionalities constitute the mainstay of nanotechnology. Interestingly, this exciting possibility of nanolevel tailoring of materials was envisioned way back in 1959 by Richard Feynman in his lecture, "There's plenty of room at the bottom." Quantum physics is the study of matter and energy at the most fundamental level. It aims to uncover the properties and behaviors of the very building blocks of nature. Nanoscience is the study of phenomenon and manipulation of materials at atomic, molecular and macro-molecule scales, where properties differ significantly from those at large scale. Nanotechnologies are the design, characterisation, production and application of structures, devices and systems by controlling shape and size at nanometre scale. Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications. What is nanomaterial? • Is defined as any material that has unique or novel properties, due to the nanoscale (nano metre-scale) structuring. • These are formed by incorporation or structuring of nanoparticles. • They are subdivided into nanocrystals, nano powders, and nanotubes: A sequence of nanoscale of C60 atoms arranged in a long thin cylindrical structure.

Advances in micro and nano fabrication technologies have enabled fabrication of smaller and more sensitive devices for applications not only in solid-state physics but also in medicine and biology. The demand for devices that can precisely transport material, specifically fluids are continuously increasing. Therefore, integration of various technologies with numerous functionalities in one single device is important. Scanning probe microscope (SPM) is one such device that has evolved from atomic force microscope for imaging to a variety of microscopes by integrating different physical and chemical mechanisms. In this article, we review a particular class of SPM devices that are suited for fluid dispensing. We review their fabrication methods, fluid-pumping mechanisms, real-time monitoring of dispensing, physics of dispensing, and droplet characterization. Some of the examples where these probes have already been applied are also described. Finally, we conclude with an outlook and future scope for these devices where femtolitre or smaller volumes of liquid handling are needed.

The adhesion and removal of particles from surfaces is a contemporary problem in many industrial applications like Semiconductor manufacturing, Bioaerosol removal, Pharmaceuticals, Adhesives and Petroleum industry. The complexity of the problem is due to the variety of factors like roughness, temperature, humidity, fluid medium etc. that affect pull-off of particles from surfaces. In particle removal from surfaces using fluid motion, the dynamic effects of particle separation will play an important role. Thus it is essential to study the dynamic effects of particle removal. Velocity of pull-off and force duration effects are two important dynamic factors that might affect pull-off. Particle adhesion studies can be made using the Atomic Force Microscope (AFM). The velocity of pull-off and force duration can be varied while making the AFM measurements. The objective of the current work is to obtain the dependence of pull-off force on pull-off velocity. Experiments were conducted using AFM and the data obtained from the experiments is processed to obtain plots for pull-off force vs. particle size and pull-off force vs. pull-off velocity. The pull-off force is compared with the iv predictions of previous contact adhesion theories. A velocity effect on pull-off force is observed from the experiments conducted. v DEDICATION To My parents and loving sister vi ACKNOWLEDGEMENTS I would like to take this opportunity to offer my heartfelt thanks to a number of people without whose help and support this thesis would never have been possible. I must start with my advisor Dr. Arun Srinivasa, for providing me with an opportunity to work with him. He has always guided me through my work and at the same time given me enough freedom to learn and produce original ideas. I would also like to express my gratitude to Dr. Denis Phares for his invaluable ideas. I would like to thank Dr. William Lackowski and Yulia Vasilyeva for providing me with training and support for doing the experiments on the Atomic Force Microscope at their Material Characterization Facility. My parents have provided me with countless opportunities for which I am extremely grateful. The love that my sister and I share in my life is invaluable to me. Nothing I say here can do justice to the continuous and unending support I get from my family. I must also thank a few friends who have been with me through the ups and downs in my life. Thank you very much Praveena, Shruti, Purna and Raghu. Last but not the least it gives me immense pleasure to thank the numerous friends who have come into my life at various stages to make it wonderful. Thank

This section outlines potential near-term target applications for systems with limited capabilities to fabricate atomically precise objects via positional control. Positional control may be achieved in several different ways, thus, this analysis makes no assumptions about how the positional control is accomplished, except where noted. By "limited capabilities," we mean:

Nanotechnologies are the technologies of the future, which have the ability to create and control objects on the scale of ~ 1 – 100 nm, with the goal of preparing new materials that have specific properties and functions. The necessary technological operations it is possible both in non-conventional domain and after classic principle, conventional. The paper showed some predictable aspects for the both domains, in possible diversion for the future. Essential, the non-conventional technologies will be presents in new conditions, not yet known, but very interesting and important.

Nanotechnologies are the technologies of the future, which have the ability to create and control objects on the scale of ~ 1 – 100 nm, with the goal of preparing new materials that have specific properties and functions. The necessary technological operations it is possible both in non-conventional domain and after classic principle, conventional. The paper showed some predictable aspects for the both domains, in possible diversion for the future. Essential, the non-conventional technologies will be presents in new conditions, not yet known, but very interesting and important.

In recent years, metabolism researches using nanomaterials have been focusing on human and animal cells, and therefore very limited data are available about influence of nanomaterials on biosynthesis of secondary metabolites in plant cells. Plants produce different types of secondary metabolites including terpenoids, phenolics, tannins, and alkaloids, which are known to act as vital mediators for the interaction with other living (biotic) or non-living (abiotic) agents under stressful conditions. Elicitors may induce physiological and biochemical processes of the target plants and activate defense mechanisms. Application of signaling molecules as elicitors has evolved an efficient technique for the production of pharmaceutically active compounds in plants. However, relatively little has been done regarding the application of nanomaterials as potential elicitors for production of industrially valuable compounds. Here, we provide studies proving that nanomaterials can function as elicitors of plant defensive chemistry that are mostly accompanied by enhanced production of different secondary metabolites.

In this paper we present an introduction to the principles and advances made in the fields of nanoscience and nanotechnology including inventions, discoveries and design and study of molecular building blocks (MBBs) studied through nanoscience and applied in nanotechnology. Nanoscience is the study of systems in nanoscale and nanotechnology is the ability to systematically organize and manipulate properties and behavior of matter in the atomic and molecular levels. Through nanoscience and nanotechnology it has become possible to study and create very useful functional devices, materials and systems on the 1 to 100 nanometer (one billionth of a meter) length scale. The reasons why nanoscale has become so important are presented. Historical aspects of nanoscience and nanotechnology are introduced starting with the famous 1959 lecture by R.P. Feynman. Considering that recent inventions, discoveries and breakthroughs in atomic and molecular aspects of nanoscale systems have been quite frequent, a selected list of recent advances and future prospects familiar to the author are presented here.