Journal articles on the topic 'Nanoscale interfacial phenomena'
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Luo, Jian, Shen J. Dillon, and Martin P. Harmer. "Interface Stabilized Nanoscale Quasi-Liquid Films." Microscopy Today 17, no. 4 (June 26, 2009): 22–27. http://dx.doi.org/10.1017/s1551929509000121.
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A unique class of impurity-based quasi-liquid films has been widely observed at free surfaces, grain boundaries (GBs), and hetero-phase interfaces in ceramic and metallic materials (Figure 1). These nanometer-thick interfacial films can be alternatively understood to be: (a) quasi-liquid layers that adopt an “equilibrium” thickness in response to a balance of attractive and repulsive interfacial forces (in a high-temperature colloidal theory) or (b) multilayer adsorbates with thickness and average composition set by bulk dopant activities [1–2]. In several model binary systems, such quasi-liquid, interfacial films are found to be thermodynamically stable well below the bulk solidus lines, provoking analogies to the simpler interfacial phenomena of premelting in unary systems [3] and prewetting in binary de-mixed liquids [4]. These interfacial films exhibit structures and compositions that are neither observed nor stable as bulk phases, as well as transport, mechanical, and physical properties that are markedly different from bulk phases.
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Agarwal, Neha, Ruma Bhattacharyya, Narendra K. Tripathi, Sanjay Kanojia, Debmalya Roy, Kingsuk Mukhopadhyay, and Namburi Eswara Prasad. "Derivatization and interlaminar debonding of graphite–iron nanoparticle hybrid interfaces using Fenton chemistry." Physical Chemistry Chemical Physics 19, no. 25 (2017): 16329–36. http://dx.doi.org/10.1039/c7cp00357a.
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SHIGA, Tomoyuki, Satoyuki KAWANO, and Kazuhiro NAKAHASHI. "Molecular dynamics simulation on interfacial phenomena in nanoscale liquid drop." Proceedings of the JSME annual meeting 2002.3 (2002): 109–10. http://dx.doi.org/10.1299/jsmemecjo.2002.3.0_109.
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Yuen1, David A., and James R. Rustad. "Workshop on Computational Studies of Interfacial Phenomena: Nanoscale to Mesoscale." Visual Geosciences 3, no. 1 (November 1998): 1–18. http://dx.doi.org/10.1007/s10069-998-1000-0.
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Zhang, Wei, Qihong Feng, Sen Wang, Xianmin Zhang, Jiyuan Zhang, and Xiaopeng Cao. "Molecular Simulation Study and Analytical Model for Oil–Water Two-Phase Fluid Transport in Shale Inorganic Nanopores." Energies 15, no. 7 (March 30, 2022): 2521. http://dx.doi.org/10.3390/en15072521.
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Shale reservoirs contain omnipresent nanopores. The fluid transport phenomena on the nanoscale are significantly different from that on the macroscale. The understandings of fluid transport behavior, especially multiphase flow, are still ambiguous on the nanoscale and the traditional hydrodynamic models are insufficient to describe the fluid flow in shale. In this work, we firstly use a molecular dynamics simulation to study the oil–water two-phase flow in shale inorganic quartz nanopores and investigated the unique interfacial phenomena and their influences on fluid transport in a confined nanospace. The results of the molecular simulation revealed that the water-oil-water layered structure was formed in quartz nanopores. There is no-slip boundary condition between water and quartz surface. The density dip and the extremely low apparent viscosity of the oil–water interface region were observed. The liquid–liquid slip effect happened at the oil–water interface. Based on the nano-effects obtained by the molecular simulation, two mathematical models were proposed to describe the nanoscale oil–water two-phase flow, considering both the solid–liquid and liquid–liquid interfacial phenomena, and the performances of two mathematical models were validated. This study shed light on the flow behaviors of oil and water on the nanoscale, and provides the theoretical basis for scale-upgrading, from the nanoscale to the macroscale.
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Landman, Uzi, and W. D. Luedtke. "Interfacial Junctions and Cavitation." MRS Bulletin 18, no. 5 (May 1993): 36–44. http://dx.doi.org/10.1557/s0883769400047102.
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Understanding the atomistic mechanisms, energetics, structure, and dynamics underlying the interactions and physical processes that occur when two materials are brought together, separated, or rub against each other (hence the term tribology, from the Greek tribos, meaning to rub) is fundamentally important to many basic and applied problems. Examples include adhesion, capillarity, contact formation, surface deformation, elastic and plastic response characteristics, hardness, micro- and nanoindentation, friction, lubrication, wear, fracture, atomic-scale probing, and modifications and manipulations of materials surfaces. These considerations have for over a century motivated extensive theoretical and experimental research into the above phenomena and their technological consequences.Explorations of materials systems and phenomena in the nanoscale regime often require experimental probes and theoretical and computational methods that allow investigations with refined spatial, as well as temporal, resolution. Consequently, until recently most theoretical approaches to the above issues, with a few exceptions, have been anchored in continuum elasticity and contact mechanics. Experimental observations and measurements of surface forces and the consequent materials response to such interactions have been macroscopic in nature.
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Franceschetti, Donald R. "Finite Element Modeling of Space Charge Phenomena on the Nanoscale." Advances in Science and Technology 46 (October 2006): 120–25. http://dx.doi.org/10.4028/www.scientific.net/ast.46.120.
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The NernstPlanckPoisson (NPP) system of equations provides a continuum model for the behavior of interfacial charge in solid ionic conductors. Despite the obvious limitations in using such models to describe systems a few atomic diameters in extent, the success of the PoissonBoltzmann equation in modeling the electrostatic interactions of individual molecules with their ionic atmospheres suggests that continuum solutions have some value as a first approximation in describing charge distributions in nanoparticles and thin layers. Except for static charge distributions onedimensional geometries, solution of the NPP equations requires numerical approximation. Here we examine the applicability of the finite element method to the study of space charge phenomena in selected 1 and 2dimensional geometries, comparison to exactly soluble onedimensional cases to gauge the validity of the results.
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Wang, Ziying, Dhamodaran Santhanagopalan, Wei Zhang, Feng Wang, Huolin L. Xin, Kai He, Juchuan Li, Nancy Dudney, and Ying Shirley Meng. "In Situ STEM-EELS Observation of Nanoscale Interfacial Phenomena in All-Solid-State Batteries." Nano Letters 16, no. 6 (May 9, 2016): 3760–67. http://dx.doi.org/10.1021/acs.nanolett.6b01119.
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Boreyko, J., P. Caveney, S. L. Norred, C. Chin, S. T. Retterer, M. L. Simpson, and C. P. Collier. "Synthetic Biology in Aqueous Compartments at the Micro- and Nanoscale." MRS Advances 2, no. 45 (2017): 2427–33. http://dx.doi.org/10.1557/adv.2017.489.
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ABSTRACTAqueous two-phase systems and related emulsion-based structures defined within micro- and nanoscale environments enable a bottom-up synthetic biological approach to mimicking the dynamic compartmentation of biomaterial that naturally occurs within cells. Model systems we have developed to aid in understanding these phenomena include on-demand generation and triggering of reversible phase transitions in ATPS confined in microscale droplets, morpho-logical changes in networks of femtoliter-volume aqueous droplet interface bilayers (DIBs) formulated in microfluidic channels, and temperature-driven phase transitions in interfacial lipid bilayer systems supported on micro and nanostructured substrates. For each of these cases, the dynamics were intimately linked to changes in the chemical potential of water, which becomes increasingly susceptible to confinement and crowding. At these length scales, where interfacial and surface areas predominate over compartment volumes, both evaporation and osmotic forces become enhanced relative to ideal dilute solutions. Consequences of confinement and crowding in cell-sized microcompartments for increasingly complex scenarios will be discussed, from single-molecule mobility measurements with fluorescence correlation spectroscopy to spatio-temporal modulation of resource sharing in cell-free gene expression bursting.
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Шебзухова, М. А., and А. А. Шебзухов. "Фазовое равновесие и поверхностные характеристики в бинарной системе, содержащей наноразмерные частицы." Физика твердого тела 60, no. 2 (2018): 390. http://dx.doi.org/10.21883/ftt.2018.02.45398.100.
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AbstractA consistent description of phase equilibrium and surface phenomena in binary systems containing monodisperse spherical nanoparticles of arbitrary (including nanoscale) size is presented in the context of the classical method with separating surfaces. Using the obtained relations, we have calculated the composition of coexisting phases and interface layer, and interfacial tension on the boundary between nanoparticles and the matrix at different temperatures in Ti-Mo system. The results of the calculations are consistent with the available experimental data.
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Chen, Lei, and Linmao Qian. "Role of interfacial water in adhesion, friction, and wear—A critical review." Friction 9, no. 1 (September 12, 2020): 1–28. http://dx.doi.org/10.1007/s40544-020-0425-4.
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Abstract Surficial water adsorption and interfacial water condensation as natural phenomena that can alter the contact status of the solid interface and tribological performances are crucial in all length scales, i.e., from earthquakes to skating at the macroscale level and even to micro/nano-electromechanical systems (M/NEMS) at the microscale/nanoscale level. Interfacial water exhibits diverse structure and properties from bulk water because of its further interaction with solid surfaces. In this paper, the evolutions of the molecular configuration of the adsorbed water layer depending on solid surface chemistry (wettability) and structure, environmental conditions (i.e., relative humidity and temperature), and experimental parameters (i.e., sliding speed and normal load) and their impacts on tribological performances, such as adhesion, friction, and wear, are systematically reviewed. Based on these factors, interfacial water can increase or reduce adhesion and friction as well as facilitate or suppress the tribochemical wear depending on the water condensation kinetics at the interface as well as the thickness and structure of the involved interfacial water.
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Falk, Guido, Alexander Nold, and Birgit Wiegand. "Advances in Microscale and Nanoscale Mechanisms of Electrophoretic Deposition in Aqueous Media." Key Engineering Materials 654 (July 2015): 23–28. http://dx.doi.org/10.4028/www.scientific.net/kem.654.23.
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The processing of ceramic thick and thin films, nano- and micro-scaled ceramic structures as well as bulk ceramics of high quality and precise dimensions under electrophoretic boundary conditions requires a full understanding of the dynamics of relevant interfacial mechanisms and interactions of colloidal phases at the nano- and micro-scale. Recent findings and latest insights on the importance of electrokinetic and electrohydrodynamic interfacial processes for membrane electrophoretic depositon in aqueous media are summarised. In this context, the paper addresses the fundamental importance of surficial charge heterogeneities, electric double layer instabilities, electrokinetically induced micro-vortex dynamics, as well as lateral and medial effective electrical field gradients. These phenomena are evaluated in terms of reasonable correlations and mechanistic coincidences of general EPD deposition principles. The experimental results are based on potentiometry, in-situ videomicroscopy, high-resolution as well as secondary electron microscopy. A numerical method for the simulation of the electrophoretic deposition process is suggested based on a multiphysical Finite Element approach given by Nernst-Planck, Poisson- and Navier-Stokes equations. The results of the simulations provide adequate agreement with experimental findings.
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Song, Subin, Glenn Villena Latag, Evan Angelo Quimada Mondarte, Ryongsok Chang, and Tomohiro Hayashi. "Experimental Characterization of Water Condensation Processes on Self-Assembled Monolayers Using a Quartz Crystal Microbalance with Energy Dissipation Monitoring." Micro 2, no. 3 (August 29, 2022): 513–23. http://dx.doi.org/10.3390/micro2030033.
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Water condensation on solid surfaces is a universal phenomenon that plays an essential role in many interfacial phenomena, such as friction, corrosion, adsorption, etc. Thus far, the initial states of water condensation on surfaces with varying chemical properties have yet to be fully explained at the nanoscale. In this study, we performed a real-time characterization of water condensation on self-assembled monolayers (SAMs) with different functional groups using quartz crystal microbalance with energy dissipation monitoring (QCM-D). We found that the kinetics of water condensatison is critically dependent on the head group chemistries. We discovered that the condensed water’s viscoelasticity cannot be predicted from macroscopic water contact angles, but they were shown to be consistent with the predictions of molecular simulations instead. In addition, we also found a highly viscous interfacial water layer on hydrophilic protein-resistant SAMs. In contrast, the interfacial water layer/droplet on either hydrophilic protein-adsorbing or hydrophobic SAMs exhibited lower viscosity. Combining our and previous findings, we discuss the influence of interfacial hydration on the viscoelasticity of condensed water.
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Banerjee, Abhik, Hanmei Tang, Xuefeng Wang, Ju-Hsiang Cheng, Han Nguyen, Minghao Zhang, Darren H. S. Tan, et al. "Revealing Nanoscale Solid–Solid Interfacial Phenomena for Long-Life and High-Energy All-Solid-State Batteries." ACS Applied Materials & Interfaces 11, no. 46 (October 23, 2019): 43138–45. http://dx.doi.org/10.1021/acsami.9b13955.
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Otto, Daniel P., and Melgardt M. de Villiers. "Why is the nanoscale special (or not)? Fundamental properties and how it relates to the design of nano-enabled drug delivery systems." Nanotechnology Reviews 2, no. 2 (April 1, 2013): 171–99. http://dx.doi.org/10.1515/ntrev-2012-0051.
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AbstractNanoscience studies describe natural phenomena at the submicron scale. Below a critical nanoscale limit, the physical, chemical, and biological properties of materials show a marked departure in their behavior compared to the bulk. At the nanoscale, energy conversion is dominated by phonons, whereas at larger scales, electrons determine the process. The surface-to-volume ratio at the nanoscale is immense, and interfacial interactions are markedly more important than at the macroscopic level, where the majority of the material is shielded from the surface. These properties render the nanoparticles to be significantly different from their larger counterparts. Nano-enabled drug delivery systems have resulted from multidisciplinary cooperation aimed at improving drug delivery. Significant improvements in the thermodynamic and delivery properties are seen due to nanotechnology. Hybrid nanodelivery systems, i.e., membranes with nanopores that can gate stimuli-responsive drug release could be a future development. Nanotechnology will improve current drug delivery and create novel future delivery systems. The fundamental properties and challenges of nanodelivery systems are discussed in this review.
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Lu, Yang, and Linbing Wang. "Nanomechanics Modeling of Interface Interactions in Asphalt Concrete: Traction and Shearing Failure Study." Journal of Multiscale Modelling 10, no. 01 (March 2019): 1841004. http://dx.doi.org/10.1142/s1756973718410044.
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The interface bonding strength is critical for asphalt concrete performance under external load applications. A thorough understanding of the load transfer mechanism bridging the nanoscale interfacial details and the macroscale properties is required to accurately predict the performance of asphalt concrete. This research presents a multiscale analysis procedure for the modeling of interface behaviors, in which material properties are evaluated by atomic scale interactions, emphasizing the complex shearing and separation mechanisms under various loading modes. The representative model system was established based on multiscale experimental characterization of the tight-bonding interface between asphalt and aggregate. Interfacial load transfer and failure studies were conducted for investigating the effect of tension and compression on shearing mode separation. The cohesive zone model parameters, such as peak traction and energy of separation were evaluated for each loading mode. Different boundary conditions were applied to obtain the representative volume element (RVE) and connection to continuum level properties. Results indicated that depending on the various loading modes, the failure of the nanoscale interface system may occur within the asphalt phase or at the interface. These results set the basis for continuum length-scale micromechanical models which may be used to determine the bulk material response, incorporating interfacial phenomena. The findings presented in this paper are consistent with observations reported in previous studies and expand on the understanding of the relationship between molecular structures and combined shearing separation failure properties of asphalt concrete interfaces.
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Okada, Atsushi, Shikun He, Bo Gu, Shun Kanai, Anjan Soumyanarayanan, Sze Ter Lim, Michael Tran, et al. "Magnetization dynamics and its scattering mechanism in thin CoFeB films with interfacial anisotropy." Proceedings of the National Academy of Sciences 114, no. 15 (March 24, 2017): 3815–20. http://dx.doi.org/10.1073/pnas.1613864114.
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Studies of magnetization dynamics have incessantly facilitated the discovery of fundamentally novel physical phenomena, making steady headway in the development of magnetic and spintronics devices. The dynamics can be induced and detected electrically, offering new functionalities in advanced electronics at the nanoscale. However, its scattering mechanism is still disputed. Understanding the mechanism in thin films is especially important, because most spintronics devices are made from stacks of multilayers with nanometer thickness. The stacks are known to possess interfacial magnetic anisotropy, a central property for applications, whose influence on the dynamics remains unknown. Here, we investigate the impact of interfacial anisotropy by adopting CoFeB/MgO as a model system. Through systematic and complementary measurements of ferromagnetic resonance (FMR) on a series of thin films, we identify narrower FMR linewidths at higher temperatures. We explicitly rule out the temperature dependence of intrinsic damping as a possible cause, and it is also not expected from existing extrinsic scattering mechanisms for ferromagnets. We ascribe this observation to motional narrowing, an old concept so far neglected in the analyses of FMR spectra. The effect is confirmed to originate from interfacial anisotropy, impacting the practical technology of spin-based nanodevices up to room temperature.
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Jeng, Yeau Ren. "Development of Innovative Algorithm for Nanomechanics and its Applications to the Characterization of Materials." Key Engineering Materials 528 (November 2012): 165–96. http://dx.doi.org/10.4028/www.scientific.net/kem.528.165.
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Understanding major mechanisms affecting material strength such as grain size, grain orientation and dislocation mechanism from atomistic viewpoint can empower scientists and engineers with the capability to produce vastly strengthened materials. Computational studies can offer the possibility of carrying out simulations of material properties at both larger length scales and longer times than direct atomistic calculations. The study has conducted theoretical modeling and experimental testing to investigate nanoscale mechanisms related to material strength and interfacial performance. Various computational algorithms in nanomechanics including energy minimization, molecular dynamics and hybrid approaches that mix atomistic and continuum methods to bridge the length and time scales have been used to thoroughly study the deformation and strengthening mechanisms. Our study has also performed experiments including depth-sensing indentation technique andin-situpico-indentation to characterize the nanomechanisms related to material strength and tribological performance. In this project, we have developed the innovative mutil-scale algorithms in the area of nanomechanics. These approaches were used to studies the defect effect on the mechanical properties of thin film, mechanical properties of nanotubes, and tribological phenomena at nanoscale interfaces.
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Stach, Sebastian, Dinara Dallaeva, Ştefan Ţălu, Pavel Kaspar, Pavel Tománek, Stefano Giovanzana, and Lubomír Grmela. "Morphological features in aluminum nitride epilayers prepared by magnetron sputtering." Materials Science-Poland 33, no. 1 (March 1, 2015): 175–84. http://dx.doi.org/10.1515/msp-2015-0036.
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AbstractThe aim of this study is to characterize the surface topography of aluminum nitride (AlN) epilayers prepared by magnetron sputtering using the surface statistical parameters, according to ISO 25178-2:2012. To understand the effect of temperature on the epilayer structure, the surface topography was investigated through atomic force microscopy (AFM). AFM data and analysis of surface statistical parameters indicated the dependence of morphology of the epilayers on their growth conditions. The surface statistical parameters provide important information about surface texture and are useful for manufacturers in developing AlN thin films with improved surface characteristics. These results are also important for understanding the nanoscale phenomena at the contacts between rough surfaces, such as the area of contact, the interfacial separation, and the adhesive and frictional properties.
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García-Pastor, Francisco Alfredo, Josué Benjamín Montelongo-Vega, Marco Vinicio Tovar-Padilla, María Antonia Cardona-Castro, and Jaime Alvarez-Quintana. "Robust Metallic Nanolaminates Having Phonon-Glass Thermal Conductivity." Materials 13, no. 21 (November 4, 2020): 4954. http://dx.doi.org/10.3390/ma13214954.
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Heat transfer phenomena in multilayer structures have gained interest due to their promising use in thermal insulation and thermoelectricity applications. In such systems, nanostructuring has been used to introduce moderate interfacial density, and it has been demonstrated that interfacial thermal resistance plays a crucial role in reducing thermal conductivity κ. Nevertheless, the main constraint for actual applications is related to their tiny size because they are extremely thin to establish appreciable temperature gradients. In this work, by severe plastic deformation process of accumulative roll bonding (ARB), a 250 µm thick Cu-Nb multilayer containing more than 8000 interfaces with periods below 40 nm was obtained, enabling the production of bulk metallic nanolaminates with ultralow κ. Multilayers present an ultralow κ of ∼0.81 W/mK at 300 K, which is 100 times smaller than its Cu-Nb bulk counterpart, and even lower than the amorphous lattice limit for the Cu-Nb thin film system. By using electron diffusive mismatch model (EDMM), we argue that both electrons diffusively scattering at interface and those ballistically crossing the constituents are responsible for heat conduction in the Cu-Nb multilayers at nanoscale. Hence, ARB Cu-Nb multilayers are intriguing candidate materials which can prove avenues to achieve stable ultralow κ thermal barriers for robust applications.
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Portavoce, Alain, and Khalid Hoummada. "Role of Atomic Transport Kinetic on Nano-Film Solid State Growth." Diffusion Foundations 17 (July 2018): 115–46. http://dx.doi.org/10.4028/www.scientific.net/df.17.115.
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Nanostructures used to build current technology devices are generally based on the stack of several thin films (from few nanometer-thick to micrometer-thick layers) having different physical properties (conductors, semiconductors, dielectrics, etc.). In order to build such devices, thin film fabrication processes compatible with the entire device fabrication need to be developed (each subsequent process step should not deteriorate the previous construction). Solid-state reactive diffusion allows thin film exhibiting good interfacial properties (mechanical, electrical…) to be produced. In this case, the film of interest is grown from the reaction of an initial layer with the substrate on which it has been deposited, during controlled thermal annealing. In the case of the reaction of a nano-layer (thickness < 100 nm) with a semi-infinite substrate, nanoscale effects can be observed: i) the phases appear sequentially, ii) not all the thermodynamic stable phases appear in the sequence (some phases are missing), and iii) some phases are transient (they disappear as fast as they appear). The understanding of the driving forces controlling such nanoscale effects is highly desired in order to control the phase formation sequence, and to stabilize the phase of interest (for the targeted application) among all the phases appearing in the sequence.This chapter presents recent investigations concerning the influence of atomic transport on the nanoscale phenomena observed during nano-film reactive diffusion. The results suggest that nano-film solid-state reaction could be controlled by modifying atomic transport kinetics, allowing current processes based on thin-film reactive diffusion to be improved.
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Bîrleanu, Corina, Marius Pustan, Florina Șerdean, and Violeta Merie. "AFM Nanotribomechanical Characterization of Thin Films for MEMS Applications." Micromachines 13, no. 1 (December 25, 2021): 23. http://dx.doi.org/10.3390/mi13010023.
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Nanotribological studies of thin films are needed to develop a fundamental understanding of the phenomena that occur to the interface surfaces that come in contact at the micro and nanoscale and to study the interfacial phenomena that occur in microelectromechanical systems (MEMS/NEMS) and other applications. Atomic force microscopy (AFM) has been shown to be an instrument capable of investigating the nanomechanical behavior of many surfaces, including thin films. The measurements of tribo-mechanical behavior for MEMS materials are essential when it comes to designing and evaluating MEMS devices. A great deal of research has been conducted to evaluate the efficiency and reliability of different measurements methods for mechanical properties of MEMS material; nevertheless, the technologies regarding manufacturing and testing MEMS materials are not fully developed. The objectivesof this study are to focus on the review of the mechanical and tribological advantages of thin film and to highlight the experimental results of some thin films to obtain quantitative analyses, the elastic/plastic response and the nanotribological behavior. The slight fluctuation of the results for common thin-film materials is most likely due to the lack of international standardization for MEMS materials and for the methods used to measure their properties.
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Costa, Marlene, Zerrin Sezgin-Bayindir, Sonia Losada-Barreiro, Fátima Paiva-Martins, Luciano Saso, and Carlos Bravo-Díaz. "Polyphenols as Antioxidants for Extending Food Shelf-Life and in the Prevention of Health Diseases: Encapsulation and Interfacial Phenomena." Biomedicines 9, no. 12 (December 14, 2021): 1909. http://dx.doi.org/10.3390/biomedicines9121909.
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Toxicity caused by the exposure to human-made chemicals and environmental conditions has become a major health concern because they may significantly increase the formation of reactive oxygen species (ROS), negatively affecting the endogenous antioxidant defense. Living systems have evolved complex antioxidant mechanisms to protect cells from oxidative conditions. Although oxidative stress contributes to various pathologies, the intake of molecules such as polyphenols, obtained from natural sources, may limit their effects because of their antioxidant and antimicrobial properties against lipid peroxidation and against a broad range of foodborne pathogens. Ingestion of polyphenol-rich foods, such as fruits and vegetables, help to reduce the harmful effects of ROS, but the use of supramolecular and nanomaterials as delivery systems has emerged as an efficient method to improve their pharmacological and therapeutic effects. Suitable exogenous polyphenolic antioxidants should be readily absorbed and delivered to sites where pathological oxidative damage may take place, for instance, intracellular locations. Many potential antioxidants have a poor bioavailability, but they can be encapsulated to improve their ideal solubility and permeability profile. Development of effective antioxidant strategies requires the creation of new nanoscale drug delivery systems to significantly reduce oxidative stress. In this review we provide an overview of the oxidative stress process, highlight some properties of ROS, and discuss the role of natural polyphenols as bioactives in controlling the overproduction of ROS and bacterial and fungal growth, paying special attention to their encapsulation in suitable delivery systems and to their location in colloidal systems where interfaces play a crucial role.
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Christiansen, Michael G., Nima Mirkhani, William Hornslien, and Simone Schuerle. "A theoretical examination of localized nanoscale induction by single domain magnetic particles." Journal of Applied Physics 132, no. 17 (November 7, 2022): 174304. http://dx.doi.org/10.1063/5.0102153.
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Single domain magnetic nanoparticles are increasingly investigated as actuators of biological and chemical processes that respond to externally applied magnetic fields. Although their localized effects have often been attributed to nanoscale heating, recent experimental evidence suggests the need to consider alternative hypotheses. Here, using the stochastic Landau–Lifshitz–Gilbert equation and finite element modeling, we investigate and critically examine an alternative hypothesis that localized effects may instead involve the induced electric fields arising from the dynamical behavior of individual single domain magnetic particles. We model the magnetization dynamics and resulting induced electric fields for two relevant and distinct cases of magnetic nanoparticles in alternating magnetic fields: (1) magnetogenetic stimulation of channel proteins associated with ferritin and (2) catalytic enhancement of electrochemical hydrolysis. For the first case, while the local electric fields that ferritin generates are shown to be insufficient to perturb the transmembrane potential, fields on the surface of its mineral core on the order of 10[Formula: see text]–10[Formula: see text] V/m may play a more plausible role in mass transport of iron ions that indirectly lead to stimulation. For the second case, our model indicates that the highest interfacial electric field strengths, on the order of 10[Formula: see text] V/m, are expected during reversal events. Thus, nanoparticles well suited for hysteresis heating can also act as intermittent sources of localized induced electric fields in response to an alternating applied field. Finally, we compare the magnitude and timescale of these electric fields to technologically relevant phenomena, showing that they are generally weaker and faster.
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Xi, Erte, Vasudevan Venkateshwaran, Lijuan Li, Nicholas Rego, Amish J. Patel, and Shekhar Garde. "Hydrophobicity of proteins and nanostructured solutes is governed by topographical and chemical context." Proceedings of the National Academy of Sciences 114, no. 51 (November 20, 2017): 13345–50. http://dx.doi.org/10.1073/pnas.1700092114.
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Hydrophobic interactions drive many important biomolecular self-assembly phenomena. However, characterizing hydrophobicity at the nanoscale has remained a challenge due to its nontrivial dependence on the chemistry and topography of biomolecular surfaces. Here we use molecular simulations coupled with enhanced sampling methods to systematically displace water molecules from the hydration shells of nanostructured solutes and calculate the free energetics of interfacial water density fluctuations, which quantify the extent of solute–water adhesion, and therefore solute hydrophobicity. In particular, we characterize the hydrophobicity of curved graphene sheets, self-assembled monolayers (SAMs) with chemical patterns, and mutants of the protein hydrophobin-II. We find that water density fluctuations are enhanced near concave nonpolar surfaces compared with those near flat or convex ones, suggesting that concave surfaces are more hydrophobic. We also find that patterned SAMs and protein mutants, having the same number of nonpolar and polar sites but different geometrical arrangements, can display significantly different strengths of adhesion with water. Specifically, hydroxyl groups reduce the hydrophobicity of methyl-terminated SAMs most effectively not when they are clustered together but when they are separated by one methyl group. Hydrophobin-II mutants show that a charged amino acid reduces the hydrophobicity of a large nonpolar patch when placed at its center, rather than at its edge. Our results highlight the power of water density fluctuations-based measures to characterize the hydrophobicity of nanoscale surfaces and caution against the use of additive approximations, such as the commonly used surface area models or hydropathy scales for characterizing biomolecular hydrophobicity and the associated driving forces of assembly.
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Ariga, Katsuhiko, Tatsuyuki Makita, Masato Ito, Taizo Mori, Shun Watanabe, and Jun Takeya. "Review of advanced sensor devices employing nanoarchitectonics concepts." Beilstein Journal of Nanotechnology 10 (October 16, 2019): 2014–30. http://dx.doi.org/10.3762/bjnano.10.198.
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Many recent advances in sensor technology have been possible due to nanotechnological advancements together with contributions from other research fields. Such interdisciplinary collaborations fit well with the emerging concept of nanoarchitectonics, which is a novel conceptual methodology to engineer functional materials and systems from nanoscale units through the fusion of nanotechnology with other research fields, including organic chemistry, supramolecular chemistry, materials science and biology. In this review article, we discuss recent advancements in sensor devices and sensor materials that take advantage of advanced nanoarchitectonics concepts for improved performance. In the first part, recent progress on sensor systems are roughly classified according to the sensor targets, such as chemical substances, physical conditions, and biological phenomena. In the following sections, advancements in various nanoarchitectonic motifs, including nanoporous structures, ultrathin films, and interfacial effects for improved sensor function are discussed to realize the importance of nanoarchitectonic structures. Many of these examples show that advancements in sensor technology are no longer limited by progress in microfabrication and nanofabrication of device structures – opening a new avenue for highly engineered, high performing sensor systems through the application of nanoarchitectonics concepts.
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Dutta, Sutapa, Stefano Corni, and Giorgia Brancolini. "Atomistic Simulations of Functionalized Nano-Materials for Biosensors Applications." International Journal of Molecular Sciences 23, no. 3 (January 27, 2022): 1484. http://dx.doi.org/10.3390/ijms23031484.
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Nanoscale biosensors, a highly promising technique in clinical analysis, can provide sensitive yet label-free detection of biomolecules. The spatial and chemical specificity of the surface coverage, the proper immobilization of the bioreceptor as well as the underlying interfacial phenomena are crucial elements for optimizing the performance of a biosensor. Due to experimental limitations at the microscopic level, integrated cross-disciplinary approaches that combine in silico design with experimental measurements have the potential to present a powerful new paradigm that tackles the issue of developing novel biosensors. In some cases, computational studies can be seen as alternative approaches to assess the microscopic working mechanisms of biosensors. Nonetheless, the complex architecture of a biosensor, associated with the collective contribution from “substrate–receptor–analyte” conjugate in a solvent, often requires extensive atomistic simulations and systems of prohibitive size which need to be addressed. In silico studies of functionalized surfaces also require ad hoc force field parameterization, as existing force fields for biomolecules are usually unable to correctly describe the biomolecule/surface interface. Thus, the computational studies in this field are limited to date. In this review, we aim to introduce fundamental principles that govern the absorption of biomolecules onto functionalized nanomaterials and to report state-of-the-art computational strategies to rationally design nanoscale biosensors. A detailed account of available in silico strategies used to drive and/or optimize the synthesis of functionalized nanomaterials for biosensing will be presented. The insights will not only stimulate the field to rationally design functionalized nanomaterials with improved biosensing performance but also foster research on the required functionalization to improve biomolecule–surface complex formation as a whole.
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Fiorenza, Patrick, Filippo Giannazzo, and Fabrizio Roccaforte. "Characterization of SiO2/4H-SiC Interfaces in 4H-SiC MOSFETs: A Review." Energies 12, no. 12 (June 17, 2019): 2310. http://dx.doi.org/10.3390/en12122310.
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This paper gives an overview on some state-of-the-art characterization methods of SiO2/4H-SiC interfaces in metal oxide semiconductor field effect transistors (MOSFETs). In particular, the work compares the benefits and drawbacks of different techniques to assess the physical parameters describing the electronic properties and the current transport at the SiO2/SiC interfaces (interface states, channel mobility, trapping phenomena, etc.). First, the most common electrical characterization techniques of SiO2/SiC interfaces are presented (e.g., capacitance- and current-voltage techniques, transient capacitance, and current measurements). Then, examples of electrical characterizations at the nanoscale (by scanning probe microscopy techniques) are given, to get insights on the homogeneity of the SiO2/SiC interface and the local interfacial doping effects occurring upon annealing. The trapping effects occurring in SiO2/4H-SiC MOS systems are elucidated using advanced capacitance and current measurements as a function of time. In particular, these measurements give information on the density (~1011 cm−2) of near interface oxide traps (NIOTs) present inside the SiO2 layer and their position with respect to the interface with SiC (at about 1–2 nm). Finally, it will be shown that a comparison of the electrical data with advanced structural and chemical characterization methods makes it possible to ascribe the NIOTs to the presence of a sub-stoichiometric SiOx layer at the interface.
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MANNA, J. S., M. K. MITRA, S. MUKHERJEE, and G. C. DAS. "HIGH DIELECTRIC CONSTANT COMPOSITE BASED ON CHLOROPHYLL A ENTRAPPED NANOPOROUS SILICA GEL." Journal of Advanced Dielectrics 02, no. 03 (July 2012): 1250016. http://dx.doi.org/10.1142/s2010135x12500166.
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Chlorophyll a (naturally occurring Mg porphyrene) has been entrapped in nano/porous silica gel using sol–gel method at room temperature, producing a stable composite. HRTEM observation reveals regular nanoscale [around 15–20 nm diameter] distribution of aggregated polycrystalline chlorophyll a within porous silica matrix. UV-vis study also corroborates the presence of various aggregated chlorophyll a species within the system. Low field measurement shows almost 400 times enhancement of dielectric constant (1700) with incorporation of only 0.125 mg/ml of chlorophyll and the loss is 0.5 at room temperature at 100 Hz. The dielectric constant of the composite reaches 2500 as chlorophyll concentration becomes 1 mg/ml. Observed strong space charge response to the external field and strong frequency dispersion of the dielectric properties of the composite can be attributed to the long-range electron delocalization [nomadic polarization] in chlorophyll a aggregates. The electric modulus (M*) formalism used in this study enabled us to distinguish and separate various relaxation processes. It is found that with increasing chlorophyll concentration D.C. relaxation time decreases exponentially at room temperature. It is shown that observed relaxations do not perfectly follow the Debye response in high frequency region due to heterogeneous distribution of chlorophyll aggregates. The low values of room temperature activation energy calculated from Arrhenius plot reveal that polaronic hopping phenomena is absent at grain-interfacial region due to low thermal energy.
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Ghanekarade, Asieh, Anh D. Phan, Kenneth S. Schweizer, and David S. Simmons. "Nature of dynamic gradients, glass formation, and collective effects in ultrathin freestanding films." Proceedings of the National Academy of Sciences 118, no. 31 (July 29, 2021): e2104398118. http://dx.doi.org/10.1073/pnas.2104398118.
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Molecular, polymeric, colloidal, and other classes of liquids can exhibit very large, spatially heterogeneous alterations of their dynamics and glass transition temperature when confined to nanoscale domains. Considerable progress has been made in understanding the related problem of near-interface relaxation and diffusion in thick films. However, the origin of “nanoconfinement effects” on the glassy dynamics of thin films, where gradients from different interfaces interact and genuine collective finite size effects may emerge, remains a longstanding open question. Here, we combine molecular dynamics simulations, probing 5 decades of relaxation, and the Elastically Cooperative Nonlinear Langevin Equation (ECNLE) theory, addressing 14 decades in timescale, to establish a microscopic and mechanistic understanding of the key features of altered dynamics in freestanding films spanning the full range from ultrathin to thick films. Simulations and theory are in qualitative and near-quantitative agreement without use of any adjustable parameters. For films of intermediate thickness, the dynamical behavior is well predicted to leading order using a simple linear superposition of thick-film exponential barrier gradients, including a remarkable suppression and flattening of various dynamical gradients in thin films. However, in sufficiently thin films the superposition approximation breaks down due to the emergence of genuine finite size confinement effects. ECNLE theory extended to treat thin films captures the phenomenology found in simulation, without invocation of any critical-like phenomena, on the basis of interface-nucleated gradients of local caging constraints, combined with interfacial and finite size-induced alterations of the collective elastic component of the structural relaxation process.
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Peng, Deli, Zhanghui Wu, Diwei Shi, Cangyu Qu, Haiyang Jiang, Yiming Song, Ming Ma, Gabriel Aeppli, Michael Urbakh, and Quanshui Zheng. "Load-induced dynamical transitions at graphene interfaces." Proceedings of the National Academy of Sciences 117, no. 23 (May 26, 2020): 12618–23. http://dx.doi.org/10.1073/pnas.1922681117.
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The structural superlubricity (SSL), a state of near-zero friction between two contacted solid surfaces, has been attracting rapidly increasing research interest since it was realized in microscale graphite in 2012. An obvious question concerns the implications of SSL for micro- and nanoscale devices such as actuators. The simplest actuators are based on the application of a normal load; here we show that this leads to remarkable dynamical phenomena in microscale graphite mesas. Under an increasing normal load, we observe mechanical instabilities leading to dynamical states, the first where the loaded mesa suddenly ejects a thin flake and the second characterized by peculiar oscillations, during which a flake repeatedly pops out of the mesa and retracts back. The measured ejection speeds are extraordinarily high (maximum of 294 m/s), and correspond to ultrahigh accelerations (maximum of 1.1×1010m/s2). These observations are rationalized using a simple model, which takes into account SSL of graphite contacts and sample microstructure and considers a competition between the elastic and interfacial energies that defines the dynamical phase diagram of the system. Analyzing the observed flake ejection and oscillations, we conclude that our system exhibits a high speed in SSL, a low friction coefficient of 3.6×10−6, and a high quality factor of 1.3×107compared with what has been reported in literature. Our experimental discoveries and theoretical findings suggest a route for development of SSL-based devices such as high-frequency oscillators with ultrahigh quality factors and optomechanical switches, where retractable or oscillating mirrors are required.
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Sung, Yung-Eun, Heejong Shin, and Jae Jeong Kim. "(Digital Presentation) Design of Metal/Metal Oxide Nanomaterials for Highly Active, Selective, and Durable Electrocatalysts." ECS Meeting Abstracts MA2022-02, no. 42 (October 9, 2022): 1553. http://dx.doi.org/10.1149/ma2022-02421553mtgabs.
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Electrocatalysis is a key part of renewable energy conversion in the future energy system. Sustainable energy conversion and chemical production require catalyst structure with high activity, durability, and product selectivity. In general, nanoscale electrocatalysts suffer various degradation phenomena during electrocatalysis, which leads to critical performance loss. Recently, the various hybrid nanostructures (such as ordered structure, metal/carbon encapsulation, or metal/metal oxide) have been highly investigated to achieve promising catalytic performances and enhanced stabilities. In this presentation, we will cover three different types of nanomaterials as highly active and stable electrocatalysts for oxygen reduction reaction (ORR). First, the alloy nanoparticles with ordered structures exhibit novel catalytic properties from their unique electronic and geometric structures. In particular, Pt alloys with atomically ordered crystal structures have been found to largely improve both electrocatalytic activity and stability for ORR through increased electronic interaction between Pt and other transition metals. Similarly, we recently demonstrated that well-controlled Co-, Mn- and Fe-based ternary or binary oxide nanocatalysts have an exceptionally high ORR activity, in addition to the promising electrocatalytic stability. Therefore, it is very important to synthesize well-ordered alloy nanocrystals to obtain highly durable and active electrocatalysts with respect to their structural and compositional properties. Second, we will show the strategic employment of carbon shells on electrocatalyst surfaces to enhance stability in the electrochemical process. Carbon shells can beneficially shield catalyst surfaces from electrochemical degradation and physical agglomeration. Thus carbon shells can effectively preserve the initial active site structure during electrocatalysis. The carbon shell also provides a confined environment at interfaces, enabling unconventional electrochemical behaviors. Finally, we will suggest an effective strategy to construct metal/oxide interfaces, precisely modulating the metal/oxide interfacial interactions in the nanoscale. By controlling the interface and strain effect on catalytic activity, we can achieve high active and stable metal oxide systems for ORR. We would like to describe the details of the above results, for investigating structure-activity relationships in electrocatalytic processes. Only when we start to comprehend the fundamentals behind electrocatalysis on the structure and interface of metal/metal oxide nanocrystals, they can be further advanced to be sustainable in long-term device operation.
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Tian, Bozhi, and Charles M. Lieber. "Design, synthesis, and characterization of novel nanowire structures for photovoltaics and intracellular probes." Pure and Applied Chemistry 83, no. 12 (October 31, 2011): 2153–69. http://dx.doi.org/10.1351/pac-con-11-08-25.
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Semiconductor nanowires (NWs) represent a unique system for exploring phenomena at the nanoscale and are expected to play a critical role in future electronic, optoelectronic, and miniaturized biomedical devices. Modulation of the composition and geometry of nanostructures during growth could encode information or function, and realize novel applications beyond the conventional lithographical limits. This review focuses on the fundamental science aspects of the bottom-up paradigm, which are synthesis and physical property characterization of semiconductor NWs and NW heterostructures, as well as proof-of-concept device concept demonstrations, including solar energy conversion and intracellular probes. A new NW materials synthesis is discussed and, in particular, a new “nano-tectonic” approach is introduced that provides iterative control over the NW nucleation and growth for constructing 2D kinked NW superstructures. The use of radial and axial p-type/intrinsic/n-type (p-i-n) silicon NW (Si-NW) building blocks for solar cells and nanoscale power source applications is then discussed. The critical benefits of such structures and recent results are described and critically analyzed, together with some of the diverse challenges and opportunities in the near future. Finally, results are presented on several new directions, which have recently been exploited in interfacing biological systems with NW devices.
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Sauvage, Xavier, and Yana Nasedkina. "The Role of Grain Boundaries and other Defects on Phase Transformations Induced by Severe Plastic Deformation." Diffusion Foundations 5 (July 2015): 77–92. http://dx.doi.org/10.4028/www.scientific.net/df.5.77.
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During the past two decades, processing of ultrafine grained materials using severe plastic deformation techniques has attracted great interest in the scientific community. Although the up-scaling of processes and the lack of ductility of ultrafine grained alloys are still some important challenges, these techniques look promising because they produce bulk materials free of porosities. More recently, some strategies to combine precipitation hardening and ultrafine grained structures have been proposed. It has also been shown that nanoscaled composite materials could be successfully processed. This experimental work rose however some very fundamental scientific questions about the influence of severe plastic deformation on the precipitation mechanisms or on the formation of supersaturated solid solution through mechanical mixing. The driving force and the thermodynamics of these phase transformations are of course affected by the high amount of energy stored in severely deformed alloys, especially as interfacial energy. But grain boundaries, with the help of dislocations and point defects, also play an important role in the kinetics. In this paper, it is proposed to shortly review these phenomena and the underlying mechanisms with a special emphasis on the contribution of grain boundaries.
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Zaghloul, U., G. J. Papaioannou, H. Wang, B. Bhushan, F. Coccetti, P. Pons, and R. Plana. "Nanoscale characterization of the dielectric charging phenomenon in PECVD silicon nitride thin films with various interfacial structures based on Kelvin probe force microscopy." Nanotechnology 22, no. 20 (March 28, 2011): 205708. http://dx.doi.org/10.1088/0957-4484/22/20/205708.
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Sachan, Pradeep, and Prakash Chandra Mondal. "Coordination-driven opto-electroactive molecular thin films in electronic circuits." Journal of Materials Chemistry C, 2022. http://dx.doi.org/10.1039/d2tc02238a.
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Surface engineering using controlled molecular structures, thickness, packing, and orientation is highly necessary for understanding nanoscale interfacial phenomena. Preparation of coordination compound-based oligomer films of well-defined chemical structures, compositions, orientation,...
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Yong, Xin, and Lucy T. Zhang. "Investigating liquid-solid interfacial phenomena in a Couette flow at nanoscale." Physical Review E 82, no. 5 (November 15, 2010). http://dx.doi.org/10.1103/physreve.82.056313.
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Milne, Zachary B., Kathryn Hasz, J. B. McClimon, Juan Castro, and Robert W. Carpick. "A modified multibond model for nanoscale static friction." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 380, no. 2232 (August 2022). http://dx.doi.org/10.1098/rsta.2021.0342.
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Several key features of nanoscale friction phenomena observed in experiments, including the stick-slip to smooth sliding transition and the velocity and temperature dependence of friction, are often described by reduced-order models. The most notable of these are the thermal Prandtl–Tomlinson model and the multibond model. Here we present a modified multibond (mMB) model whereby a physically-based criterion—a critical bond stretch length—is used to describe interfacial bond breaking. The model explicitly incorporates damping in both the cantilever and the contacting materials. Comparison to the Fokker–Planck formalism supports the results of this new model, confirming its ability to capture the relevant physics. Furthermore, the mMB model replicates the near-logarithmic trend of increasing friction with lateral scanning speed seen in many experiments. The model can also be used to probe both correlated and uncorrelated stick slip. Through greater understanding of the effects of damping and noise in the system and the ability to more accurately simulate a system with multiple interaction sites, this model extends the range of frictional systems and phenomena that can be investigated. This article is part of the theme issue ‘Nanocracks in nature and industry’.
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Luo, Jian, Vivek K. Gupta, and Haijun Qian. "Interface-Stabilized Nanoscale Quasi-Liquid Films and Interfacial Prewetting and Premelting Transitions." MRS Proceedings 979 (2006). http://dx.doi.org/10.1557/proc-979-0979-hh04-08.
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AbstractEquilibrium-thickness, intergranular films (IGFs) have been observed in various ceramic materials. Recently, surficial amorphous films (SAFs) of similar character have also been found. Furthermore, a series of studies revealed the stabilization of disordered (quasi-liquid) IGFs and SAFs well below the bulk solidus or eutectic temperatures, wherein analogies to the phenomena of premelting and prewetting can be made. Accordingly, combined interfacial premelting and prewetting models have been developed using a diffuse-interface theory. This paper outlines the key results of two model experiments in support of the above theory: namely observation of quasi-liquid grain boundary films (metallic IGFs) in W-Ni and searching of a complete wetting transition for Bi2O3 on ZnO where SAFs become macroscopically thick. We propose that simple combined interfacial premelting and prewetting models apply to metallic IGFs, but only serve as a basis to understand IGFs and SAFs in ceramics where additional interactions, e.g. dispersion forces and space-charges, should be added separately and may result in more complex behaviors.
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Shan, Wanfei, and Weidong Luo. "Charge transfer and metal-insulator transition in (CrO2)m/(TaO2)n superlattices." Journal of Physics: Condensed Matter, July 14, 2022. http://dx.doi.org/10.1088/1361-648x/ac8133.
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Abstract Various interfacial emergent phenomena have been discovered in tunable nanoscale materials, especially in artificially designed epitaxial superlattices. In conjunction, the atomically fabricated superlattices have exhibited a plethora of exceptional properties compared to either bulk materials separately. Here, the (CrO2)m/(TaO2)n superlattices composed of two lattice-matched metallic metal oxides are constructed. With the help of first-principle density-functional theory calculations, a computational and theoretical study of (CrO2)m/(TaO2)n superlattices manifests the interfacial electronic properties in detail. The results suggest that emergent properties result from the charge transfer from the TaO2 to CrO2 layers. At two special ratios of 1 : 1 and 1 : 2 between m and n, the superlattices undergo metal-to- insulator transition. Additionally, the bands below the Fermi level become narrower with the increasing thickness of the CrO2 and TaO2 layers. The study reveals that the electronic reconstruction at the interface of two metallic materials can generate interesting physics, which points the direction for the manipulation of functionalities in artificial superlattices or heterostructures within a few atomic layers.
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Papaefthymiou, Georgia C., A. Bustamante, and Rosa B. Scorzelli. "Mössbauer Characterization of Iron Oxide Nanoclusters Grown within Aluminosilicate Matrices." MRS Proceedings 746 (2002). http://dx.doi.org/10.1557/proc-746-r5.1.
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ABSTRACTMössbauer spectroscopy uses the resonant absorption of nuclear radiation by 57Fe to probe the electronic and internal magnetic structure of iron based magnetic materials. The technique has a characteristic measuring time of 10 ns enabling investigation of spin relaxation phenomena in nanoscale particles; and determination of their magnetic properties in the absence of externally applied magnetic fields. We report on Mössbauer studies of γ-Fe2O3 nanoparticles synthesized within hexagonally packed mesoporous MCM-41 aluminosilicate matrices with cylindrical pores of 2.5 nm diameter. Data analysis allowed differentiation of particle-matrix interfacial versus particle-core interior iron sites. Interfacial iron atoms experience large electric field gradients resulting in quadrupole splitting values of ΔEq (surface) = (1.25 ± 0.05) mm/s, while core atoms exhibit smaller values of δEq (core) = (0.73± 0.05) mm/s at room temperature. Similarly, differences were observed in the values of the internal hyperfine fields at low temperatures indicating reduced strength in the exchange interactions at the particle surface, with interfacial atoms experiencing internal fields Hhf (surface) = (458 ± 1) kOe reduced relative to the core Hhf (core) = (488 ±1) kOe at 4.2 K. Particle/matrix interactions at the surface appear to perturb the electronic interactions deeper into the core than the magnetic exchange interactions.
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Torii, Daichi, Taku Ohara, and Kenji Ishida. "Molecular-Scale Mechanism of Thermal Resistance at the Solid-Liquid Interfaces: Influence of Interaction Parameters Between Solid and Liquid Molecules." Journal of Heat Transfer 132, no. 1 (October 23, 2009). http://dx.doi.org/10.1115/1.3211856.
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The solid-liquid interfacial thermal resistance is getting more and more important as various solid-liquid systems are utilized in nanoscale, such as micro electro-mechanical systems/nano electro-mechanical systems (MEMS/NEMS) with liquids and nanoparticle suspension in liquids. The present paper deals with the transport of thermal energy through the solid-liquid interfaces, and the goal is to find a molecular-scale mechanism that determines the macroscopic characteristics of the transport phenomena. Nonequilibrium molecular dynamics simulations have been performed for systems of a liquid film confined between atomistic solid walls. The two solid walls have different temperatures to generate a steady thermal energy flux in the system, which is the element of macroscopic heat conduction flux. Three kinds of liquid molecules and three kinds of solid walls are examined, and the thermal energy flux is measured at the control surfaces in the liquid film and at the solid-liquid interfaces. The concept of boundary thermal resistance is extended, and it is defined for each degree of freedom of translational motion of the molecules. It is found that the interaction strength between solid and liquid molecules uniformly affects all boundary thermal resistances defined for each degree of freedom; the weaker interaction increases all the resistances at the same rate and vice versa. The boundary thermal resistances also increase when the solid and liquid molecules are incommensurate, but the incommensurability has a greater influence on the boundary thermal resistances corresponding to the molecular motion parallel to the interface than that for the normal component. From these findings it is confirmed that the thermal resistance for the components parallel to the interface is associated with the molecular-scale corrugation of the surface of the solid wall, and that the thermal resistance for the component normal to the interface is governed by the number density of the solid molecules that are in contact with the liquid.
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Chen, Xi, Baoxing Xu, and Ling Liu. "Nanoscale Fluid Mechanics and Energy Conversion." Applied Mechanics Reviews 66, no. 5 (May 29, 2014). http://dx.doi.org/10.1115/1.4026913.
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Under nanoconfinement, fluid molecules and ions exhibit radically different configurations, properties, and energetics from those of their bulk counterparts. These unique characteristics of nanoconfined fluids, along with the unconventional interactions with solids at the nanoscale, have provided many opportunities for engineering innovation. With properly designed nanoconfinement, several nanofluidic systems have been devised in our group in the past several years to achieve energy conversion functions with high efficiencies. This review is dedicated to elucidating the unique characteristics of nanofluidics, introducing several novel nanofluidic systems combining nanoporous materials with functional fluids, and to unveiling their working mechanisms. In all these systems, the ultra-large surface area available in nanoporous materials provides an ideal platform for seamlessly interfacing with nanoconfined fluids, and efficiently converting energy between the mechanical, thermal, and electrical forms. These systems have been demonstrated to have great potentials for applications including energy dissipation/absorption, energy trapping, actuation, and energy harvesting. Their efficiencies can be further enhanced by designing efforts based upon improved understanding of nanofluidics, which represents an important addition to classical fluid mechanics. Through the few systems exemplified in this review, the emerging research field of nanoscale fluid mechanics may promote more exciting nanofluidic phenomena and mechanisms, with increasing applications by encompassing aspects of mechanics, materials, physics, chemistry, biology, etc.
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Pesquera, David, Abel Fernández, Ekaterina Khestanova, and Lane W. Martin. "Freestanding Complex-Oxide Membranes." Journal of Physics: Condensed Matter, July 2, 2022. http://dx.doi.org/10.1088/1361-648x/ac7dd5.
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Abstract Complex oxides show a vast range of functional responses, unparalleled within the inorganic solids realm, making them promising materials for applications as varied as next-generation field-effect transistors, spintronics, electro-optic modulators, pyroelectric detectors, or oxygen reduction catalysts. Their stability in ambient conditions, chemical versatility, and large susceptibility to minute structural and electronic modifications make them ideal subjects of study to discover emergent phenomena and to generate novel functionalities for next-generation devices. Recent advances in the synthesis of single-crystal, freestanding complex oxide membranes provide an unprecedented opportunity to study these materials in a nearly-ideal system (e.g., free of mechanical/thermal interaction with substrates) as well as expanding the range of tools for tweaking their order parameters (i.e., (anti-)ferromagnetic, (anti-)ferroelectric, ferroelastic), and increasing the possibility of achieving novel heterointegration approaches (including interfacing dissimilar materials) by avoiding the chemical, structural, or thermal constraints in synthesis processes. Here, we review the recent developments in the fabrication and characterization of complex-oxide membranes and discuss their potential for unraveling novel physicochemical phenomena at the nanoscale and for futher exploiting their functionalities in technologically relevant devices.