The oil droplets contained in wastewater often caused considerable troubles in wastewater treatment. Especially for the oil-water emulsions containing oil droplets with small particle size. The engineers and the researchers are always pursuing advanced materials and technology to deal with them.

Recently, a polymer with a quaternary amine structure was synthesized in our laboratory. We have applied such polymer to sterilization and separation of oil-water emulsions and achieved good results.

When such a monomer is specifically polymerized in sponges having particular pore structure, the emulsion-containing wastewater was separated perfectly(efficiency > 99%). Besides, these sponges exhibited a surprising automatic demulsification effect in just a few minutes. The application of the basic principles of electrostatic adsorption, concentration diffusion, aggregation, and density convection are used to explain the mechanism of the automatic demulsification effect. We believed that the discovery of this phenomenon will help the academic and engineering communities to develop more efficient automatic demulsification sponges in the near future.

In recent years, moleoularly imprinted polymers (MIPs) have attracted considerable interests for their applications in biotechnology. MIPs possess selective and specific cavities for recognition and binding of the target molecules with high affinity and specificity. The interactions between the polymer and the target molecules consist of electrostatic interactions, hydrogen bonds, Van der Waals forces, and hydrophobic interactions.

In this study, a luminescent molecular imprinting polymer nanocomposite was prepared via the encapsulation approach. The LiYF₄:Yb³⁺_0.25/Er³⁺_0.01/Tm³⁺_0.01/Ho³⁺_0.01@LiYF₄:Yb³⁺_0.2 and LiYF₄:Yb³⁺_0.25/Tm³⁺_0.01@LiYF₄:Yb³⁺_0.2 core/shell upconversion nanoparticles (UCNPs) were prepared as the luminescent nanoparticles by thermal decomposition method. The [Poly(methacrylic acid)-co-octadecene] (P(MAA-co-OD)) copolymer was synthesized as the moleoularly-imprinted polymer and imprinted with the templates of glycine, bovine serum albumin and bovine hemoglobin. The prepared UCNP@P(MAA-co-OD) MIP nanocomposite (MIP-NC) could emit green and red and UV/Vis light respectively. Both luminescent bands could be absorbed by the template molecules and the biomolecules to be recognized.

The particle size of MIP-NC determined by dynamic light scattering (DLS) showed that the size was in the range of 1.30 mm to 1.95 mm. Thermogravimetric analysis (TGA) indicated that the weight ratio of UCNPs in the MIP-NC was ca. 2%. The recognition and re-adsorption effect of the luminescent MIP-NC for the three template molecules after molecular imprinting were determined by the absorption intensity of the ultraviolet-visible (UV/Vis) spectra and photoluminescence (PL) measurements.

The prepared MIP-NC was used as a biosensor for recognition of human red blood cells and ractopamine. The UV/Vis analysis showed that the adsorption of human red blood cells by the synthesized MIP-NC was better than that of ractopamine. Photoluminescence spectra and the result of Stern-Volmer equation indicated that the light quenching effect of human red blood cell was higher than that of ractopamine. Therefore, the MIP-NC prepared in this study has a better recognition effect on human red blood cells.

Silver nanoparticles inhibit the activity of the enzyme providing oxygen exchange in protozoa, such as pathogenic bacteria, viruses, and fungi (about 700 species of pathogenic flora and fauna) [1]. The transition from the ionic Ag⁺ form to metallic nanoclusters makes it possible to reduce silver’s toxicity to cells of higher organisms without suppression of the antimicrobial activity against pathogenic microflora. Silver nanoparticles, especially stabilized ones, have greater stability and prolonged action [2]. Sodium carboxymethylcellulose (Na-CMC) - a water - soluble film forming biodegradable polymer widely used in the production of oral pharmaceuticals and drugs for external use primarily to increase the viscosities of ointments, in the production of pastes as hydrogel bases, and in the production of drugs for parenteral use - is of high interest as a stabilizer of silver nanoparticles. In addition, Na-CMC is utilized as a binding and disintegrating agent in the production of tablets. Na-CMC is one of the key components of adhesive absorbing systems employed to treat problematic wounds, to remove extravasates, sweat, and the contents of wounds, and to regulate the kinetics of release of active substances of systems contacting mucous membranes.

The aim of this study is to prepare stabilized silver nanoparticles in polymer films based on Na-CMC and to investigate their structures, physical and chemical properties, and microbicidal activities.

Industrial samples of Na-CMC with degrees of substitution of 0.65-0.85 and degrees of polymerization of 200-600 obtained from cotton cellulose were used as polymer matrices after their purification from inorganic and organic admixtures. To prepare silver nanoparticles in the films based on CMC, AgNO₃ aqueous solutions of various concentrations were utilized. The bacterium Staphylococcus epidermidis and the yeast fungus Candida albicans - pathogens of humans and animals-were used as test cultures.

To form the films, 2-4% aqueous solutions of purified Na-CMC samples with various degrees of substitution and polymerization were employed after the removal of the gel fraction via centrifugation with a laboratory centrifuge at 2500 rpm for 20 min. Then, calculated amounts of 0.1-0.001 M aqueous solutions of AgNO₃ and 0.1-0.5% glycerol, which played the role of a plasticizer, were added under stirring to the gel free Na-CMC solutions, and the stirring was continued until homogeneous Ag⁺CMC^– hydrogels formed.

The photochemical reduction of silver ions in the Ag⁺CMC^– structure to nanoparticles was performed at 25°Ð¡ through their irradiation with a DB-250 high pressure mercury lamp. The dispersions of silver nanoparticles were prepared via ultrasonic dispersion of the hydrogels with the use of UZDN-1 and U-4.2 ultrasonic dispersers.

Solubility and degree of purity is one of most important physico-chemical characteristics of Na-CMC, determined possibility of their conversion into products. We were investigated compound of fractions of water soluble and insoluble of purified of Na-CMC samples with various DS and DP.

You can see from the table 1 with increasing DS, quota of soluble Na-CMC fraction in water was increased, and content of insoluble gel fraction decreased. With increasing DS, quota of gel fraction of Na-CMC, in water decreases.

This can be explained by the fact that by increasing the DS, of Na-CMC, intensity of hydrogen bonds between the macromolecules Na-CMC decreases. Moreover, the compounds and properties of the gel fraction Na-CMC, depend on the type of cellulose row material and methods obtaining of Na-CMC.

It was found that the Na-CMC samples of cotton pulp, in all intervals DP and DS, the content of gel fraction is more than of the sample Na-CMC obtained from wood cellulose. This is explained by the different morphological structures of cotton and wood cellulose, and lower reactivity of cotton cellulose, subjected to carboxymethylation reaction. The above-described investigation provided as polymeric base for the obtaining hydrogel Na-CMC containing ions and silver nanoparticles. Further studies were investigations on the formation and stabilization of silver ions and nanoparticles in Na-CMC polymer base and studied their properties.

At the first step of the study, the films were prepared from aqueous solutions of a-CMC with various degrees of substitution and polymerization and their physical and mechanical parameters were examined. The films were applied onto glass plates from a 2% aqueous solution of Na-CMC. The Na-CMC film formed during water removal.

In the next step of the study, Na-CMC films stabilized with silver nanoparticles were formed and then photoirradiated.

Photoreduction of silver cations at concentrations of 0.025-2.50 wt % was performed in a 2% solution of Na-CMC with a degree of substitution of 0.85 (pH 8.5) and a degree of polymerization of 600.

After an increase in the initial concentration of AgNO₃ from 0.025 to 2.5 wt %, the UV - induced color of the Na-CMC solution was found to change from pale yellow to brown. Such a change is likely due to the increase in the amount of formed silver nanoparticles of different sizes. Meanwhile, a pure Na-CMC solution did not change color and remained clear after UV-irradiation.

To confirm the formation of silver nanoparticles, electron microscopic investigations of CMC films were performed. Figure 1 shows the electron micrographs of Na-CMC films formed under UV - irradiation that contain 0.025-2.5 wt % silver nitrate.

For the purpose of determination of the forms and sizes of silver nanoparticles in structure Na-CMC were investigate of obtained samples by atomic fors microscope tipe АFМ - 5500 (Austria).

From Fig. 1a, it may be concluded that, during photoirradiation at a AgNO₃ concentration of 0.025 wt % AgNO₃, clusters and nanoparticles of silver with sizes 2-30 nm are formed in the structures of the films of Na-CMC. After the addition of 0.25 wt. % AgNO₃, 5 to 35 nm spherical silver nanoparticles are formed in the structures of the Na-CMC films (Fig. 1b).

An increase in the silver nitrate concentration in the Na-CMC structure up to 2.5 wt % induces an increase in the number of 5 to 35 nm silver nanoparticles, and rod shaped silver nanoparticles 50-140 nm [3] in length and 15-45 nm in width are formed simultaneously (Fig. 1c). Thus, an increase in the silver ion content in the Na-CMC films leads to a relatively narrow size distribution of the spherical and rod shaped silver nanoparticles formed during photoirradiation.

The microbicidal activities of the samples of Na-CMC films containing silver cations and nanoparticles were examined with the use of the opportunistic test cultures Staphylococcus epidermidis and Candida albicans. To identify an antimicrobial effect, the samples of the composites were placed into test tubes containing a thioglycolic medium in the case of Staphylococcus epidermidis or Saburo in the case of Candida albicans.

Microbiological examinations showed that all the samples manifested antimicrobial activities of varying degrees against opportunistic pathogens of humans.

In addition, Na-CMC films containing Ag clusters proved to be less active then those containing 5-35 nm silver nanoparticles. This result may be explained by the fact that the total content of silver nanoparticles in such Na-CMC films turned out to be almost an order of magnitude less than that in the samples of films containing 5-35 nm silver nanoparticles. Because the concentration of silver ions in the Na-CMC hydrogels utilized for the film formation was low (0.023%), they almost completely associated with carboxylate anions of Na-CMC. It is this limited mobility of ions that is responsible for the lower rate of silver nanoparticle formation that seems to occur only in a “nanoreactor” structure [5].

Determined, optimal conditions of formation of silver nanoparticles with different shapes and sizes in structure CMC film with different DS and DP.

It is established that to restoration, first of all, are subject replaced cations silver in macromolecules Na-CMC which carry out a role «nanoreactors» where the negative ion carboxylic groups under the theory of Mott-Gurney is «trap» for positively charged ions of silver and process photostimulated formations silver nanoparticles. It is developed the UV- spectroscopic method control of the form and sizes silver nanoparticles at process their restoration.

It is established that depending on concentration of polymeric substrate, ions of silver and conditions UV - irradiations in structure Na-CMC are formed with the various sizes stabilised of silver nanoparticle spherical and rod - like forms. Formation conditions of the various form and sizes of silver nanoparticles depending on parametres of reaction of interaction of components and photochemical restoration are revealed.

Correlation dependence between the size and form silver nanoparticles in structure Na-CMC and their biological activity is established. It is shown that at decreasing in the sizes the silver nanoparticles promotes increase of their bactericidal activity at their identical concentration in polymeric matrix that speaks difference of values of the area of surface nanoparticles the various form and sizes.

The prepared biodegradable Na-CMC films containing silver nanoparticles are of interest as bactericidal and bacteriostatic coatings for the treatment of burns and trophic ulcers.

The modern generation of data storage technology brings new challenges to existing materials for low power data processing, reliable, fast and sizable transfer of data¹. In this context, artificial multiferroic composites based on ferromagnetic (FM) and ferroelectric (FE) phases that exhibit strong magnetoelectric coupling, hold promise for designing new generation memory devices with several advantages. Multiferroic composites offer innovative approaches for non-volatile memory devices as compared to their semiconductor transistor-based competitors². The organic thin memories are particularly favorable due to their environment friendly nature, low fabrication cost and mechanical flexibility³. Here, a room temperature paradigm two level nonvolatile memory operation have been demonstrated by utilizing the nonlinear magnetoelectric effects in flexible multiferroic SmFeO₃/P(VDF-TrFE) nanocomposite films. Strain induced interface interactions between  ferromagnetic and ferroelectric phases in SmFeO₃/P(VDF-TrFE) nanocomposite films allow electric field controlled magnetization behaviour. The sign of magnetoelectric coupling coefficient (α) for the composite films can be repeatedly switched between positive and negative by applying electric fields. This can be used to store binary information for non volatile memory devices. The magnetoelectric response and the required voltage for switching of α can be tuned by varying the magnetic phase fraction (SmFeO₃ nanoparticles) in nanocomposite films. Hence, flexible magnetoelectric SmFeO₃/P(VDF-TrFE) nanocomposite films can be utilized for nonvolatile memory applications with practical characteristics such as simple compact structure, easy reading/writing operation, fast speed and low power consumption.