This paper proposes a new strategy for producing thin films of TiO2 with embedded gold nanoparticles (TiO2/AuNP). One of the main tasks was the synthesis of a stable dispersion of TiO2 and gold nanoparticles in an aqueous solution of... more
This paper proposes a new strategy for producing thin films of TiO2 with embedded gold nanoparticles (TiO2/AuNP). One of the main tasks was the synthesis of a stable dispersion of TiO2 and gold nanoparticles in an aqueous solution of ethylene glycol, suitable for inkjet printing—ink with complex gold nanoparticles (AuCNP ink). The AuCNP were synthesized by a reduction from tetrachloroauric acid in the presence of TiO2 nanoparticles and ethylene glycol (EG). The final formation of TiO2/AuNP films occurred during the annealing of AuCNP layers, inkjet printed on a glass substrate. The TiO2/AuNP films demonstrate absorbance in the yellow-green range due to the localized surface plasmon resonance (LSPR) and are promising for solar cell application.
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Abstract In this article, we reveal the effect of ultralow concentration of Y dopant on the formation, structure peculiarities and optical properties of yttrium-doped ZnO (YZO) films. The YZO films were deposited on glass substrates at... more
Abstract In this article, we reveal the effect of ultralow concentration of Y dopant on the formation, structure peculiarities and optical properties of yttrium-doped ZnO (YZO) films. The YZO films were deposited on glass substrates at 250 °C and at room temperature (HT and RT, correspondingly) with the magnetron co-sputtering method in a direct current (DC) regime. The Y content in the ZnO matrix was varied by DC power applied to the Y target, and did not exceed 0.14 and 0.11 at.% for RT and HT regimes, correspondingly. For the first time it was revealed that the presence of ultralow Y dopant in the co-sputtering process at RT abruptly increases the growth rate of the YZO films by 20%, enlarges the size of crystallites and degree of texture, and cardinally changes the morphology. For the HT regime, the smooth increasing of the deposition rate and the morphological changing of the YZO films with an increase in the Y content were registered. The deposited YZO films demonstrated a high level of optical transparency in the visible and IR region. Ultralow Y doping of ZnO led to decreasing of the bandgap width. The ZnO and YZO films possessed the resistivity typical for insulators even at the highest Y content at both RT and HT deposition regimes.
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A micro-boat self-propelled by a camphor engine, carrying seed crystals of FeCl3, promoted the evolution of chemical gardens when placed on the surface of aqueous solutions of potassium hexacyanoferrate. Inverse chemical gardens (growing... more
A micro-boat self-propelled by a camphor engine, carrying seed crystals of FeCl3, promoted the evolution of chemical gardens when placed on the surface of aqueous solutions of potassium hexacyanoferrate. Inverse chemical gardens (growing from the top downward) were observed. The growth of the “inverse” chemical gardens was slowed down with an increase in the concentration of the potassium hexacyanoferrate. Heliciform precipitates were formed under the self-propulsion of the micro-boat. A phenomenological model, satisfactorily describing the self-locomotion of the camphor-driven micro-boat, is introduced and checked.
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Hierarchical metallic surfaces demonstrating pronounced water and oil repellence are reported. The surfaces were manufactured with stainless-steel microporous meshes, which were etched with perfluorononanoic acid. As a result, a... more
Hierarchical metallic surfaces demonstrating pronounced water and oil repellence are reported. The surfaces were manufactured with stainless-steel microporous meshes, which were etched with perfluorononanoic acid. As a result, a hierarchical relief was created, characterized by roughness at micro- and sub-microscales. Pronounced superoleophobicity was registered with regard to canola, castor, sesame, flax, crude (petroleum), and engine oils. Relatively high sliding angles were recorded for 5 μL turpentine, olive, and silicone oil droplets. The stability of the Cassie-like air trapping wetting state, established with water/ethanol solutions, is reported. The omniphobicity of the surfaces is due to the interplay of their hierarchical relief and surface fluorination.
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The self-propulsion of a heavy, superoleophobic, metallic micro-boat carrying a droplet of various aqueous alcohol solutions as a fuel tank is reported. The micro-boat is driven by the solutocapillary Marangoni flow. The jump in the... more
The self-propulsion of a heavy, superoleophobic, metallic micro-boat carrying a droplet of various aqueous alcohol solutions as a fuel tank is reported. The micro-boat is driven by the solutocapillary Marangoni flow. The jump in the surface tension owing to the condensation of alcohols on the water surface was established experimentally. Maximal velocities of the self-propulsion were registered as high as 0.05m/s. The maximal velocity of the center mass of the boat correlates with the maximal change in the surface tension, due to the condensation of alcohols. The mechanism of the self-locomotion is discussed. The phenomenological dynamic model describing the self-propulsion is reported.
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The work is devoted to luminescent properties of trivalent lanthanide complexes dispersed in thermoplastic host matrices. Polyethylene-based film and polypropylene-based rod both doped with these complexes were manufactured using an... more
The work is devoted to luminescent properties of trivalent lanthanide complexes dispersed in thermoplastic host matrices. Polyethylene-based film and polypropylene-based rod both doped with these complexes were manufactured using an extrusion technique. Two kinds ...
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The fine structure of the three-phase (triple) line was studied for different liquids, various topographies of micro-rough substrates and various wetting regimes. Wetting of porous and pillar-based micro-scaled polymer surfaces was... more
The fine structure of the three-phase (triple) line was studied for different liquids, various topographies of micro-rough substrates and various wetting regimes. Wetting of porous and pillar-based micro-scaled polymer surfaces was investigated. The triple line was visualized with the environmental scanning electron microscope and scanning electron microscope for the "frozen" triple lines. The value of the roughness exponent ζ for water (ice)/rough polymer systems was located within 0.55-0.63. For epoxy glue/rough polymer systems somewhat lower values of the exponent, 0.42 < ζ < 0.54, were established. The obtained values of ζ were close for the Cassie and Wenzel wetting regimes, different liquids, and different substrates' topographies. Thus, the above values of the exponent are to a great extent universal. The switch of the exponent, when the roughness size approaches to the correlation length of the defects, is also universal.
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Wetting transitions were studied with vertically-vibrated drops on various artificial and natural rough substrates. Alternative pathways of wetting transitions were observed. The model of wetting transition is presented. Multiple minima... more
Wetting transitions were studied with vertically-vibrated drops on various artificial and natural rough substrates. Alternative pathways of wetting transitions were observed. The model of wetting transition is presented. Multiple minima of the Gibbs free energy of a drop deposited on a rough surface explain alternative pathways of wetting transitions. We demonstrate that a wetting transition occurs when the constant force resulting from vibrations, Laplace and hydrostatic pressure acts on the triple line. It is shown that the final wetting states are mainly the Cassie impregnating wetting state with water penetrating the pores in the outer vicinity of the droplet or the Wenzel state with water inside the pores under the droplet whereas the substrate ahead the drop is dry.
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... Roman Pogreb1, Oleg Popov2, Vlad Lirtsman2, Oleg Pyshkin3, Alexander Kazachkov4, Albina Musin1, Gene Whyman1, Binyamin Finkelshtein5, Yuri Shmukler5, Dan Davidov2, Alexander Gladkikh6 and Edward ... 18. Cho A, Kim S-Ye, Lee M, Kim SJ,... more
... Roman Pogreb1, Oleg Popov2, Vlad Lirtsman2, Oleg Pyshkin3, Alexander Kazachkov4, Albina Musin1, Gene Whyman1, Binyamin Finkelshtein5, Yuri Shmukler5, Dan Davidov2, Alexander Gladkikh6 and Edward ... 18. Cho A, Kim S-Ye, Lee M, Kim SJ, Kim CH, Pyun CH. ...
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ABSTRACT The behavior of water droplets deposited on a polymer solution/air interface has been studied. Encapsulation of water droplets with polymer films was observed for solutions based on chlorinated & aromatic solvents, and... more
ABSTRACT The behavior of water droplets deposited on a polymer solution/air interface has been studied. Encapsulation of water droplets with polymer films was observed for solutions based on chlorinated & aromatic solvents, and amorphous polymers. The possibility of producing thin polymer films(including composite ones) is demonstrated. Analysis of the specific surface energies of the interfaces involved in the process easily explains the observed encapsulation. The kinetics of the process is connected with evaporation of the moving solution layer. A mathematical model of the encapsulation process is proposed. The presented experimental data are important for understanding the water-assisted self-assembly with rapidly evaporated polymer solutions.
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The effect of contact angle hysteresis (CAH) was studied on various polymer substrates with traditional and new experimental techniques. The new experimental technique presented in the article is based on the slow deformation of the... more
The effect of contact angle hysteresis (CAH) was studied on various polymer substrates with traditional and new experimental techniques. The new experimental technique presented in the article is based on the slow deformation of the droplet, thus CAH is studied under the constant volume of the drop in contrast to existing techniques when the volume of the drop is changed under the measurement. The energy of hysteresis was calculated in the framework of the improved Extrand approach. The advancing contact angle established with a new technique is in a good agreement with that measured with the needle-syringe method. The receding angles measured with three experimental techniques demonstrated a very significant discrepancy. The force pinning the triple line responsible for hysteresis was calculated.
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Water and glycerol marbles coated with various powders and immersed in organic liquids gave rise to water-in-oil and glycerol-in-oil Pickering-like emulsions. Non-polar oils such as polydimethylsiloxane, toluene, xylenes and chlorinated... more
Water and glycerol marbles coated with various powders and immersed in organic liquids gave rise to water-in-oil and glycerol-in-oil Pickering-like emulsions. Non-polar oils such as polydimethylsiloxane, toluene, xylenes and chlorinated solvents supported the formation of emulsions, whereas polar liquids such as dimethylsulfoxide, N,N,-dimethylformamide, acetone and ethanol did not. It is demonstrated that there is a direct contact between a liquid filling the immersed marble and the surrounding liquid. A phenomenological theory of the marbles' sinking into emulsion is proposed.
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ABSTRACT The effective surface tension of liquid marbles coated with polyvinylidene fluoride, polytetrafluoroethylene, lycopodium, carbon black and hydrophobized SiO2 powder particles is discussed. It was established with the... more
ABSTRACT The effective surface tension of liquid marbles coated with polyvinylidene fluoride, polytetrafluoroethylene, lycopodium, carbon black and hydrophobized SiO2 powder particles is discussed. It was established with the pendant-droplet method under inflation and deflation (evaporation) of liquid marbles. The effective surface tension depends strongly on the marble volume and demonstrates the pronounced hysteretic behavior. The phenomenological model predicting the linear dependence of the effective surface tension of marbles on their inverse surface area is proposed. The model is validated experimentally. Three “surface phases” are distinguished under inflation and deflation of marbles, some of which are featured by the predicted linear dependence of the effective surface tension on the inverse surface area of marbles. It turned out that the notion of the effective surface tension of a surface covered with solid particles is ambiguous, since this quantity depends on the pathway of its measurement and on the marble size.
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ABSTRACT We report patterns comprising non-spherical microscopic pores obtained under dewetting of polymer solutions of chlorinated solvents and amorphous polymers deposited on the pre-stretched polyethylene substrates. Patterns on meso-... more
ABSTRACT We report patterns comprising non-spherical microscopic pores obtained under dewetting of polymer solutions of chlorinated solvents and amorphous polymers deposited on the pre-stretched polyethylene substrates. Patterns on meso- and microscopic scales were observed. Mesoscopically scaled pattern is practically insensitive to the mechanical strain, whereas small scale microscopic voids were highly deformed, and demonstrated the average eccentricity as high as 0.25. Introduction of PEG and RTV polyorganosiloxanes/silanes destroyed the large scale pattern, thus honeycomb pattern comprising non-spherical microscopic pores has been obtained. The patterns demonstrate a potential for polymer ferroelectret applications.
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ABSTRACT Effective surface tension of liquid marbles was measured by three independent experimental techniques: vibration, shape analysis, and maximal marble height. Marbles obtained with various powders: polyvinylidene fluoride,... more
ABSTRACT Effective surface tension of liquid marbles was measured by three independent experimental techniques: vibration, shape analysis, and maximal marble height. Marbles obtained with various powders: polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, and lycopodium, were studied. The effective surface tension depends strongly on the kind of powder coating the marble. The capillary interaction between particles coating the marble was involved for qualitative interpretation of the reported data.
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... [6] N. Pike, D. Richard, W. Foster and L. Mahadevan, How aphids lose their marbles, Proceedings of the Royal Society B 269 (2002), p. 1211. [7] D. Vella, P. Aussillous and L. Mahadevan, Elasticity of an interfacial particle raft,... more
... [6] N. Pike, D. Richard, W. Foster and L. Mahadevan, How aphids lose their marbles, Proceedings of the Royal Society B 269 (2002), p. 1211. [7] D. Vella, P. Aussillous and L. Mahadevan, Elasticity of an interfacial particle raft, Europhys. Lett. ... Int. Ed. 47 (2008), pp. 50435045. ...
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ABSTRACT Poly(vinylidenefluoride) film (PVDF) doped with Eu(III)(NO3)3(o -Phenanthroline)2 complex (complex A ) was manufactured using an extrusion technique. Emission spectrum of the film was compared to spectra of the dopant and... more
ABSTRACT Poly(vinylidenefluoride) film (PVDF) doped with Eu(III)(NO3)3(o -Phenanthroline)2 complex (complex A ) was manufactured using an extrusion technique. Emission spectrum of the film was compared to spectra of the dopant and polyethylene based film. Stretching the film resulted in a sharp growth of intensity and reshaping of the luminescence spectrum. The impact of the PVDF matrix on the photoluminescence spectra of complex A is attributed to the Stark effect. Reasons for the increase of luminescence intensity are discussed. Quantum chemical calculations revealed a marked longwave shift of the lowest triplet and singlet energy levels of complex A compared to free phenanthroline. The amplification and frequency shifting of the luminescent spectrum of europium-complex-doped PVDF may lead to promising applications.