The Growth of Phosphonium Gold Nanoparticles in Alkaline Media: Kinetics and Mechanism of the Process

Colloid Journal - It has been found that the addition of ammonia water to a gold sol obtained by the Duff method induces the growth of the gold particles. The growth kinetics of such particles in...     

Zinc phthalocyanine-based water-soluble thiolated photosensitizer and its conjugates with gold nanoparticles: Synthesis and spectral properties

A new photosensitizer, monoconjugate of zinc octa-4,5-carboxy-phthalocyanine with L-cysteine, which is rather readily soluble in water, has been synthesized and characterized. The chemisorption of its molecules on the surface of gold nanoparticles with different sizes has been studied. A comparative analysis of the spectral characteristics of the synthesized conjugates of gold nanoparticles with the photosensitizer has shown that the photosensitizer grafted to gold nanoparticles exhibits rather intense fluorescence. Therefore, such conjugates can be used for photodynamic therapy of tumors.     

Metal nanoparticles on polymer surfaces: 6. Probing of non-glassy polystyrene surface layer

Peculiarities of the state of the surface layer of the amorphous glassy polymer polystyrene are studied with a specially developed experimental approach. The essence of the method consists in the observation via atomic force microscope for the depth and rate of embedding of gold nanoparticles in a polymer after their preliminary adsorption on the polymer surface from hydrosol. It is shown that the polymer glass-transition temperature near the boundary with air is substantially lowered relative to its bulk value. “Equilibrium” thickness of the non-glassy (“melted”) surface layer is determined through analysis of the data on the kinetics of nanoparticle embedding, and it is revealed that the layer thickness increases with temperature, reaching, near the “bulk” glass-transition temperature, the magnitude that is close to the diameter of the macromolecular coil. The results obtained are analyzed with allowance for published data, and the semi-empirical formula describing variations in the thickness of the non-glassy surface layer as a function of temperature in the interval between the “surface” and “bulk” glass-transition temperatures of a polymer is proposed.     

Synthesis of Bifunctional Silica Container Particles on Antiseptic Micelles with Solubilized Curcumin and Assessment of Their Biological Activity

Colloid Journal - The features of the synthesis of SiO2 mesoporous container particles (MCPs) using a hybrid template represented by miramistin micelles with curcumin solubilized in them have been...     

The influence of optical activity on the intensity and polarization parameters of transmitted light in crystals

The ellipticity and azimuth of light transmitted through an optically active plate and the intensity of this light transmitted through an analyzer are theoretically investigated as functions of the rotation angle of the plate. Relationships describing these parameters are considered. It is demonstrated that, depending on the angle of inclination of the plate, the optical activity can affect the characteristics of the transmitted light differently. A technique for determining the optical activity parameters is proposed from analyzing the relationships for the light intensity. The conoscopic figures of uniaxial and biaxial optically active crystals are described.     

Bogoliubov’s metric as a global characteristic of the family of metrics in the Hilbert algebra of observables

We comparatively analyze a one-parameter family of bilinear complex functionals with the sense of “deformed” Wigner-Yanase-Dyson scalar products on the Hilbert algebra of operators of physical observables. We establish that these functionals and the corresponding metrics depend on the deformation parameter and the extremal properties of the Kubo-Martin-Schwinger and Wigner-Yanase metrics in quantum statistical mechanics. We show that the Bogoliubov-Kubo-Mori metric is a global (integral) characteristic of this family. It occupies an intermediate position between the extremal metrics and has the clear physical sense of the generalized isothermal susceptibility. We consider the example for the SU(2) algebra of observables in the simplest model of an ideal quantum spin paramagnet.     

Invariant Integrals for the Equilibrium Problem for a Plate with a Crack

We consider the equilibrium problem for a plate with a crack. The equilibrium of a plate is described by the biharmonic equation. Stress free boundary conditions are given on the crack faces. We introduce a perturbation of the domain in order to obtain an invariant Cherepanov–Rice-type integral which gives the energy release rate upon the quasistatic growth of a crack. We obtain a formula for the derivative of the energy functional with respect to the perturbation parameter which is useful in forecasting the development of a crack (for example, in study of local stability of a crack). The derivative of the energy functional is representable as an invariant integral along a sufficiently smooth closed contour. We construct some invariant integrals for the particular perturbations of a domain: translation of the whole cut and local translation along the cut.     

Sol–Gel Synthesis of SiO<Subscript>2</Subscript> Containers Using Micelles of an Anionic Corrosion Inhibitor as a Template and the Prospects of Creation Protective Coatings Based on Them

It has been shown that silica container particles can be loaded with large amounts of an anionic corrosion inhibitor, sodium N-oleyl sarcosinate, at the stage of the sol?gel synthesis of the particles by using its micelles as a template. When incorporated into paint and varnish coatings, such containers efficiently protect low-carbon steel and D16 aluminum alloy from corrosion under severe conditions of neutral salt spray.     

Erratum to: Asymptotic Justification of the Models of Thin Inclusions in an Elastic Body in the Antiplane Shear Problem

Journal of Applied and Industrial Mathematics - An Erratum to this paper has been published: https://doi.org/10.1134/S1990478921030170     

Comparative study of the properties of silver hydrosols prepared by “citrate” and “citrate-sulfate” procedures

Comparative study of the properties of silver hydrosols prepared with the use of two classical procedures (“citrate” and “citrate-sulfate”) is performed. The possibility of using these procedures for the synthesis of stable monodisperse silver hydrosols with particle diameters of 20 nm and more is studied. The effect of the main parameters of synthesis (the ratio of initial components, the rate of their mixing, etc) on the hydrosol characteristics is investigated. It is revealed that, in the case of “citrate” synthesis, it is quite impossible to realize conditions ensuring the reproducible preparation of colloidal solutions with particles having sufficiently uniform size and shape. The procedure for the one-stage preparation of “citrate-sulfate” hydrosol (without multiple precipitation-redispersion of nanoparticles) is elaborated and it is shown that the thus prepared hydrosol is greatly superior in both the optical characteristics and the morphological uniformity of particles to the citrate sol. An increase in synthesis temperature to 100°C leads to a substantial enhancement of the stability of colloidal solution. The possibility of using “citrate-sulfate” hydrosol for the design of two-dimensional ensembles of silver nanoparticles on the quartz and silicon surfaces modified with poly(2-vinylpyridine) is demonstrated. It is shown that such ensembles possess optical properties that allow to use them in designing “two-dimensional” polymer-metal nanocomposites potentially suitable for using as active media in devices working on the principle of surface plasmon resonance.