Chuiko Institute of Surface Chemistry

Kiev, Ukraine

Chuiko Institute of Surface Chemistry

Kiev, Ukraine

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Gun'ko V.M.,Chuiko Institute of Surface Chemistry | Savina I.N.,University of Brighton | Mikhalovsky S.V.,University of Brighton | Mikhalovsky S.V.,Nazarbayev University
Advances in Colloid and Interface Science | Year: 2013

Experimental results on polymer, protein, and composite cryogels and data treatment methods used for morphological, textural, structural, adsorption and diffusion characterisation of the materials are analysed and compared. Treatment of microscopic images with specific software gives quantitative structural information on both native cryogels and freeze-dried materials that is useful to analyse the drying effects on their structure. A combination of cryoporometry, relaxometry, thermoporometry, small angle X-ray scattering (SAXS), equilibrium and kinetic adsorption of low and high-molecular weight compounds, diffusion breakthrough of macromolecules within macroporous cryogel membranes, studying interactions of cells with cryogels provides a consistent and comprehensive picture of textural, structural and adsorption properties of a variety of cryogels. This analysis allows us to establish certain regularities in the cryogel properties related to narrow (diameter 0.4100 μm) with boundary sizes within modified life science pore classification. Particular attention is paid to water bound in cryogels in native superhydrated or freeze-dried states. At least, five states of water-free unbound, weakly bound (changes in the Gibbs free energy-ΔG<0.5-0.8 kJ/mol) and strongly bound (-ΔG>0.8 kJ/mol), and weakly associated (chemical shift of the proton resonance δH=1-2 ppm) and strongly associated (δH= 3-6 ppm) waters can be distinguished in hydrated cryogels using 1H NMR, DSC, TSDC, TGand othermethods.Different software for image treatment or developed to analyse the data obtained with the adsorption, diffusion, SAXS, cryoporometry and thermoporometrymethods and based on regularisation algorithms is analysed and used for the quantitative morphological, structural and adsorption characterisation of individual and composite cryogels, including polymers filled with solid nano- or microparticles. © 2012 Elsevier B.V. All rights reserved.


Gun'ko V.M.,Chuiko Institute of Surface Chemistry
Journal of Theoretical and Computational Chemistry | Year: 2013

Modeling of water structure at a surface of different adsorbents, as well as an influence of dissolved compounds or co-adsorbates on bound water, is of importance to understand the temperature dependence of the characteristics of bound water, especially at T < 273 K, in comparison with bulk water. 1H NMR spectra giving useful information on the water structure can be obtained using different ways such as experimental measurements, direct ab initio and density functional theory (DFT) calculations or estimation using semiempirical calculations and appropriate calibration functions. Here, application of the last approach is analyzed with respect to a variety of relatively large hydrated systems. Despite the simplicity of this approach, it gives quantitative characterization of structural features of interfacial water and effects of different co-adsorbates and adsorbent surfaces on bound water. © 2013 World Scientific Publishing Company.


Gun'Ko V.M.,Chuiko Institute of Surface Chemistry
Applied Surface Science | Year: 2014

A self-consistent regularization (SCR) procedure applied to integral adsorption equations based on a complex model with slit-shaped and cylindrical pores and voids between spherical nonporous particles packed in random aggregates (SCV model) for two or three types of components (activated carbon, carbon black, silica gel, fumed silica) in composites gives more clear pictures of pore size distributions (PSD) than nonlocal density functional theory (NLDFT) or quenched solid DFT (QSDFT) methods. Results of this approach for individual adsorbents are comparable with the results of NLDFT or QSDFT methods using complex pore models (slit/cylindrical or slit/cylindrical/spherical pores). The SCV/SCR method is useful to study the textural features of hybrid materials, the PSD of which is difficult to be calculated using standard approaches. The PSD of complex materials can also be estimated using (1) high-resolution microscopic methods (e.g. HRTEM) with software (Fiji/ImageJ) used for quantitative treatment of images; (2) cryoporometry based on low-temperature 1H NMR spectroscopy; and (3) small angle X-ray scattering (SAXS). Results of these methods can effectively amplify results of the standard adsorption methods. © 2014 Elsevier B.V. All rights reserved.


Whitby R.L.D.,University of Brighton | Korobeinyk A.,University of Brighton | Glevatska K.V.,Chuiko Institute of Surface Chemistry
Carbon | Year: 2011

Acid-base titrations were used to assess the covalent reactivity of carboxylic groups on single-layer graphene oxides (SLGO) or hydrazine-reduced analogues (SLGR) when treated with thionyl chloride and subsequent coupling to amines. Reflux with aggressive solvents led to size reduction and folding of individual sheets as well as loss of carboxylic groups, substantially so for SLGR. Room temperature treatment of SLGO with a carbodiimide collapsed the sheets into star-like clusters, which exhibited poor subsequent reactivity with amines. Ultimately, conventional chemical treatment of carboxylic groups on SLGO leads to morphological changes and reduced reactivity, which may potentially limit their use. © 2010 Elsevier Ltd. All rights reserved.


Mudrak I.,Chuiko Institute of Surface Chemistry
Ionics | Year: 2014

New nanostructured composite system (1 - x)penton/xAgI (where 0 < x < 1) was synthesized by a solution-based technique, which involves the process of modification of polymer surface. Samples of the composite system were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and electrical impedance spectroscopy. It was shown that AgI nanoparticles form a continuous layer at the surface of penton particles and consist mainly of cubic γ-phase with a small amount of hexagonal β-phase. Maximum conductivity enhancement at almost one order of magnitude higher compared to the pristine AgI has been observed for the sample with x = 0.5. The overall activation energy for conduction varies from 0.23 to 0.38 eV, depending on the content of γ-phase of silver iodide in the samples. Two percolation thresholds has been also recorded at the points x = 0.1 and x = 0.3. © 2013 Springer-Verlag Berlin Heidelberg.


Whitby R.L.D.,University of Brighton | Mikhalovsky S.V.,University of Brighton | Gun'ko V.M.,Chuiko Institute of Surface Chemistry
Carbon | Year: 2010

Multi-walled carbon nanotube (MWCNT) columns are formed from the frit compression of a random distribution of MWCNTs in a casting solvent; its drying led to the formation of hyperboloid geometry. Uniaxial loading of MWNT columns mimics an open-cell foam behaviour and possesses an expansion rate in excess of 250 mm min-1 and an elastic modulus of 10-12 MPa, thus superior to conventional low-density flexible foams. Successive compression-expansion cycling within the Hookean region reveals a hysteresis loop in the stress-strain curve that stabilises at a final value of εF = 18%, but on contact with its casting solvent and subsequent drying, the sample can be regenerated to within εR = 6% according to a memory effect and is repeatable in successive stress cycles and solvent regeneration. The system was modelled for the macroscopic stress-strain behaviour of the MWCNT column to reveal the contributions of linear dependence, elasticity-plasticity and elasticity-plasticity with hardening, revealing good agreement with the stress-strain data. MWCNT columns should prove useful as an energy adsorbing device. © 2009 Elsevier Ltd. All rights reserved.


Gun'ko V.M.,University of Brighton | Gun'ko V.M.,Chuiko Institute of Surface Chemistry | Nasiri R.,University of Brighton | Sazhin S.S.,University of Brighton
Fluid Phase Equilibria | Year: 2014

The evaporation rate (γ) of n-alkane molecules in the C8-C27 range from molecular clusters and nanodroplets is analysed using the quantum chemical solvation model (SMD) and the kinetic gas theory, assuming that the system is in a state of thermodynamic equilibrium (evaporation and condensation rates are equal). The droplet size, liquid density, evaporation enthalpy and Gibbs free energy of evaporation are calculated at 300-640K. The quantum chemical calculations (SMD/HF or SMD/B3LYP methods with the 6-31G(d,p) basis set) are used to estimate changes in the Gibbs free energy during the transfer of a molecule from a liquid medium (clusters or nanodroplets) into the gas phase. The kinetic gas theory is used to estimate the collision rate of molecules/clusters/nanodroplets in the gas phase. This rate depends on partial pressures, temperature, sizes and masses of molecules and clusters/nanodroplets. An increase in the molecular size of evaporated alkanes from octane to heptacosane results in a strong decrease in the values of γ. Preliminary estimates of the evaporation/condensation coefficient, based on the direct analysis of the collisions of individual molecules with molecular clusters, are presented. © 2014.


News Article | November 10, 2016
Site: www.eurekalert.org

Scientists from the Moscow Institute of Physics and Technology (MIPT), Semenov Institute of Chemical Physics of the Russian Academy of Sciences (ICP RAS), and Chuiko Institute of Surface Chemistry of the National Academy of Sciences of Ukraine (ISC NASU) have proposed a model nanosized dipole photomotor based on the phenomenon of light-induced charge redistribution. Triggered by a laser pulse, this tiny device is capable of directed motion at a record speed and is powerful enough to carry a certain load. The research findings were published in the Journal of Chemical Physics. "The unprecedented characteristics of dipole photomotors based on semiconductor nanoclusters offer the prospect of more than just addressing a certain scarcity of the translational photomotors family. These devices could actually be applied wherever rapid nanoparticle transport is required. In chemistry and physics, they could help develop new analytical and synthetic instruments, while in biology and medicine they could be used to deliver drugs to diseased tissues, improve gene therapy strategies, and so on," says Prof. Leonid Trakhtenberg of the Department of Molecular and Chemical Physics at MIPT, who is the leader of the research team and the head of the Laboratory of Functional Nanocomposites at ICP RAS. Prof. Trakhtenberg collaborated with Prof. Viktor Rozenbaum, who heads the Department of Theory of Nanostructured Systems at ISC NASU, to develop the theory of photoinduced molecular transport. This theory provides a framework for the design of nanomachines, whose motion can be controlled by a laser. The scientists have established the relationship between several model parameters (e.g., particle dimensions, photoexcitation conditions etc.) and the key performance characteristic of the device--its average velocity. Directed nanomotors have prototypes in nature. Living organisms make use of protein devices driven by external nonequilibrium processes of a different nature, which are known as Brownian, or molecular motors. They are capable of converting random Brownian motion into directed translational motion, reciprocation, or rotation. Brownian motors are involved in muscle contraction, cell mobility (flagellar motility of bacteria), and the intra- and intercellular transport of organelles and relatively large particles of various substances (e.g., phagocytosis, or "cell eating", and elimination of metabolic waste products from the cell). These devices operate with an amazingly high efficiency approaching 100%. "Understanding the underlying mechanisms of the operation of naturally occurring molecular motors enables us not only to replicate them but also to design new highly efficient multifunctional artificial devices that could eventually be applied in nanorobotics. For the last several decades, researchers and engineers in various fields have been working together and making some real progress towards the development of controllable nanomachines. The results of their work were recognized as a highly relevant achievement and a significant advance in science and technology, when the 2016 Nobel Prize in Chemistry was awarded 'for the design and synthesis of molecular machines,'" says Prof. Rozenbaum. A Brownian motor operates by switching between at least two discrete states, which is achieved by means of chemical reactions, thermal action, AC signals, or light pulses. In the latter case, the device is referred to as a photomotor. About ten years ago, a model was developed to describe the work of a translational dipole photomotor that operates due to photoexcitation of the molecule (particle) into a state with a dipole moment different from that in the ground state. The larger the difference between the total dipole moments of the nanoparticle in the two energy states, the higher the average velocity and efficiency of the motor. The proposed motor is activated by a resonant laser pulse, which excites electrons in the cylinder-shaped semiconductor nanocluster causing a separation of charges and giving rise to an electrostatic interaction between the particle and the polar substrate. Subjecting the nanocylinder to periodic resonant laser pulses causes its potential energy in the field of the substrate to vary with time, which in turn enables directed motion (see diagram). Photomotors based on inorganic nanoparticles outperform their organic molecule based counterparts in terms of efficiency and average velocity. In a cylinder-shaped semiconductor nanocluster, the value of the dipole moment before irradiation is close to zero, but photoexcitation of an electron from the bulk to the surface gives rise to an enormous dipole moment (approx. 40 D for a cylinder with a height of ca 15 Å). "Owing to the fact that the parameters of the device have been optimized, our proposed model photomotor based on a semiconductor nanocylinder moves at a record speed of 1 mm/s, which is approximately three orders of magnitude faster than similar models based on organic molecules or motor proteins in living organisms," the authors of the study told us.


Home > Press > Scientists come up with light-driven motors to power nanorobots of the future: Researchers from Russia and Ukraine propose a nanosized motor controlled by a laser with potential applications across the natural sciences and medicine Abstract: Scientists from the Moscow Institute of Physics and Technology (MIPT), Semenov Institute of Chemical Physics of the Russian Academy of Sciences (ICP RAS), and Chuiko Institute of Surface Chemistry of the National Academy of Sciences of Ukraine (ISC NASU) have proposed a model nanosized dipole photomotor based on the phenomenon of light-induced charge redistribution. Triggered by a laser pulse, this tiny device is capable of directed motion at a record speed and is powerful enough to carry a certain load. The research findings were published in the Journal of Chemical Physics. "The unprecedented characteristics of dipole photomotors based on semiconductor nanoclusters offer the prospect of more than just addressing a certain scarcity of the translational photomotors family. These devices could actually be applied wherever rapid nanoparticle transport is required. In chemistry and physics, they could help develop new analytical and synthetic instruments, while in biology and medicine they could be used to deliver drugs to diseased tissues, improve gene therapy strategies, and so on," says Prof. Leonid Trakhtenberg of the Department of Molecular and Chemical Physics at MIPT, who is the leader of the research team and the head of the Laboratory of Functional Nanocomposites at ICP RAS. Prof. Trakhtenberg collaborated with Prof. Viktor Rozenbaum, who heads the Department of Theory of Nanostructured Systems at ISC NASU, to develop the theory of photoinduced molecular transport. This theory provides a framework for the design of nanomachines, whose motion can be controlled by a laser. The scientists have established the relationship between several model parameters (e.g., particle dimensions, photoexcitation conditions etc.) and the key performance characteristic of the device--its average velocity. Brownian motors Directed nanomotors have prototypes in nature. Living organisms make use of protein devices driven by external nonequilibrium processes of a different nature, which are known as Brownian, or molecular motors. They are capable of converting random Brownian motion into directed translational motion, reciprocation, or rotation. Brownian motors are involved in muscle contraction, cell mobility (flagellar motility of bacteria), and the intra- and intercellular transport of organelles and relatively large particles of various substances (e.g., phagocytosis, or "cell eating", and elimination of metabolic waste products from the cell). These devices operate with an amazingly high efficiency approaching 100%. "Understanding the underlying mechanisms of the operation of naturally occurring molecular motors enables us not only to replicate them but also to design new highly efficient multifunctional artificial devices that could eventually be applied in nanorobotics. For the last several decades, researchers and engineers in various fields have been working together and making some real progress towards the development of controllable nanomachines. The results of their work were recognized as a highly relevant achievement and a significant advance in science and technology, when the 2016 Nobel Prize in Chemistry was awarded 'for the design and synthesis of molecular machines,'" says Prof. Rozenbaum. A Brownian motor operates by switching between at least two discrete states, which is achieved by means of chemical reactions, thermal action, AC signals, or light pulses. In the latter case, the device is referred to as a photomotor. About ten years ago, a model was developed to describe the work of a translational dipole photomotor that operates due to photoexcitation of the molecule (particle) into a state with a dipole moment different from that in the ground state. The larger the difference between the total dipole moments of the nanoparticle in the two energy states, the higher the average velocity and efficiency of the motor. Laser triggering The proposed motor is activated by a resonant laser pulse, which excites electrons in the cylinder-shaped semiconductor nanocluster causing a separation of charges and giving rise to an electrostatic interaction between the particle and the polar substrate. Subjecting the nanocylinder to periodic resonant laser pulses causes its potential energy in the field of the substrate to vary with time, which in turn enables directed motion (see diagram). Photomotors based on inorganic nanoparticles outperform their organic molecule based counterparts in terms of efficiency and average velocity. In a cylinder-shaped semiconductor nanocluster, the value of the dipole moment before irradiation is close to zero, but photoexcitation of an electron from the bulk to the surface gives rise to an enormous dipole moment (approx. 40 D for a cylinder with a height of ca 15 Å). "Owing to the fact that the parameters of the device have been optimized, our proposed model photomotor based on a semiconductor nanocylinder moves at a record speed of 1 mm/s, which is approximately three orders of magnitude faster than similar models based on organic molecules or motor proteins in living organisms," the authors of the study told us. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | November 11, 2016
Site: www.cemag.us

Scientists from the Moscow Institute of Physics and Technology (MIPT), Semenov Institute of Chemical Physics of the Russian Academy of Sciences (ICP RAS), and Chuiko Institute of Surface Chemistry of the National Academy of Sciences of Ukraine (ISC NASU) have proposed a model nanosized dipole photomotor based on the phenomenon of light-induced charge redistribution. Triggered by a laser pulse, this tiny device is capable of directed motion at a record speed and is powerful enough to carry a certain load. The research findings were published in the Journal of Chemical Physics. “The unprecedented characteristics of dipole photomotors based on semiconductor nanoclusters offer the prospect of more than just addressing a certain scarcity of the translational photomotors family. These devices could actually be applied wherever rapid nanoparticle transport is required. In chemistry and physics, they could help develop new analytical and synthetic instruments, while in biology and medicine they could be used to deliver drugs to diseased tissues, improve gene therapy strategies, and so on,” says Prof. Leonid Trakhtenberg of the Department of Molecular and Chemical Physics at MIPT, who is the leader of the research team and the head of the Laboratory of Functional Nanocomposites at ICP RAS. Prof. Trakhtenberg collaborated with Prof. Viktor Rozenbaum, who heads the Department of Theory of Nanostructured Systems at ISC NASU, to develop the theory of photoinduced molecular transport. This theory provides a framework for the design of nanomachines, whose motion can be controlled by a laser. The scientists have established the relationship between several model parameters (e.g., particle dimensions, photoexcitation conditions etc.) and the key performance characteristic of the device—its average velocity. Brownian Motors Directed nanomotors have prototypes in nature. Living organisms make use of protein devices driven by external nonequilibrium processes of a different nature, which are known as Brownian, or molecular motors. They are capable of converting random Brownian motion into directed translational motion, reciprocation, or rotation. Brownian motors are involved in muscle contraction, cell mobility (flagellar motility of bacteria), and the intra- and intercellular transport of organelles and relatively large particles of various substances (e.g., phagocytosis, or “cell eating”, and elimination of metabolic waste products from the cell). These devices operate with an amazingly high efficiency approaching 100%. “Understanding the underlying mechanisms of the operation of naturally occurring molecular motors enables us not only to replicate them but also to design new highly efficient multifunctional artificial devices that could eventually be applied in nanorobotics. For the last several decades, researchers and engineers in various fields have been working together and making some real progress towards the development of controllable nanomachines. The results of their work were recognized as a highly relevant achievement and a significant advance in science and technology, when the 2016 Nobel Prize in Chemistry was awarded ‘for the design and synthesis of molecular machines,’” says Prof.  Rozenbaum. A Brownian motor operates by switching between at least two discrete states, which is achieved by means of chemical reactions, thermal action, AC signals, or light pulses. In the latter case, the device is referred to as a photomotor. About ten years ago, a model was developed to describe the work of a translational dipole photomotor that operates due to photoexcitation of the molecule (particle) into a state with a dipole moment different from that in the ground state. The larger the difference between the total dipole moments of the nanoparticle in the two energy states, the higher the average velocity and efficiency of the motor. Laser Triggering The proposed motor is activated by a resonant laser pulse, which excites electrons in the cylinder-shaped semiconductor nanocluster causing a separation of charges and giving rise to an electrostatic interaction between the particle and the polar substrate. Subjecting the nanocylinder to periodic resonant laser pulses causes its potential energy in the field of the substrate to vary with time, which in turn enables directed motion. Photomotors based on inorganic nanoparticles outperform their organic molecule based counterparts in terms of efficiency and average velocity. In a cylinder-shaped semiconductor nanocluster, the value of the dipole moment before irradiation is close to zero, but photoexcitation of an electron from the bulk to the surface gives rise to an enormous dipole moment (approx. 40 D for a cylinder with a height of ca 15 Å). “Owing to the fact that the parameters of the device have been optimized, our proposed model photomotor based on a semiconductor nanocylinder moves at a record speed of 1 mm/s, which is approximately three orders of magnitude faster than similar models based on organic molecules or motor proteins in living organisms,” the authors of the study told us.

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