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1
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Synthesis and aqueous solution properties of homologous gemini surfactants with different head groups

100%
Sun Y., Feng Y., Dong H., Chen Z., Han L.
Open Chemistry
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2007
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vol. 5
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issue 2
620-634
EN
A series of homologous gemini surfactants possessing identical hydrophobic chains but different ionic head groups (cationic, anionic, zwitterionic) were synthesized, and their aqueous solution properties were examined. The results showed that the surface activities of gemini surfactants are superior to those of corresponding conventional monomeric surfactants, and molecular arrangements of gemini surfactants at the air-water interface are tighter than those of corresponding conventional surfactants. It was also found that zwitterionic gemini surfactant possesses the highest surface activity among the three surfactants. The behavior at the air-water interface is closely related to the molecular structural features of surfactants, which provide an indication for synthesizing highly-efficient surfactants. [...]
2
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CHARACTERISATION OF CHITOSAN/HYALURONIC ACID BLEND FILMS MODIFIED BY COLLAGEN

88%
Lewandowska K., Alina S., Grabska S., Michalska M.
Progress on Chemistry and Application of Chitin and its Derivatives
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2017
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vol. 22
125-134
EN
In the present study, thin films based on the blends of chitosan (Ch) and hyaluronic acid (HA) with and without collagen (Coll) were characterised using tensile tests, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis (TGA). Ch/HA and Ch/HA/Coll polymer blends were prepared using the solvent evaporation technique. The interactions between polymer components in the binary and ternary blends were studied by FTIR analysis. Mechanical properties were studied and compared with those of simple polymer films. These results show that the addition of collagen into Ch/HA blends led to the increase of tensile strength and Young modulus. Moreover, it was found that the thermal stability of the Ch/HA binary blend significantly increased upon the addition of collagen.
3
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THE INFLUENCE OF THE TYPE SOLVENT ON THE STRUCTURE OF CHITOSAN BLENDS WITH HYALURONIC ACID

88%
Lewandowska K., Sionkowska A., Grabska S.
Progress on Chemistry and Application of Chitin and its Derivatives
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2016
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vol. 21
147-153
EN
The influence of the type solvent on the structure of chitosan, hyaluronic acid and their blend films was investigated. Aqueous acetic acid, hydrochloric acid, sodium chloride and aqueous acetic acid/NaCl were used as solvents for chitosan, hyaluronic acid and Ch/HA solution blends. Ch, HA and their blend films were prepared by casting technique. The homogeneity and morphology of chitosan blends were ascertained from the tapping-mode atomic force microscopy (AFM) and scanning electron microscopy (SEM). The changes of topography images are considered by determining the root mean square (RMS, Rq) deviation in the image data. The surface roughness of chitosan, hyaluronic acid and Ch/HA blended films was altered by mixing. The structure of chitosan blends with hyaluronic acid depends on the blend composition and on the solvent used for preparing the blend.
4
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Surface properties of some carotenoids spread in monolayers at the air/water interface. Experimental and computational approach

88%
Horovitz O., Tomoaia G., Racz C., Mocanu A., Bobos L.-D., Tomoaia-Cotisel M.
Open Chemistry
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2006
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vol. 4
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issue 3
489-501
EN
The surface pressure versus molecular area isotherms of some carotenoids: β,β-carotene-4-one (echinenone, ECH), β,β-carotene-4,4′-dione (canthaxanthin, CAN) and 4,4′-diapo-ω,ω-carotene-4,4′-dial (APO), spread at the air/water interface, are reported. A van der Waals type state equation is used to describe the high molecular area portions of the compression isotherms and interaction parameters within monolayers are derived. Quantum chemical semi-empirical SCF MO calculations (AM1 and PM3) are performed for the optimized geometries of molecules and dipole moments are calculated. Similar theoretical magnitudes are obtained by both methods. Surface properties, like collapse pressure, surface compressional modulus and interaction parameters are discussed in terms of dipole-dipole interactions, and correlations with the calculated quantities for the carotenoid molecules are analyzed. The orientation of the different carotenoid molecules in the monolayer is discussed.
5
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Aerogel nanoscale magnesium oxides as a destructive sorbent for toxic chemical agents

88%
Štengl V., Bakardjieva S., Maříková M., Šubrt J., Opluštil F., Olšanská M.
Open Chemistry
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2004
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vol. 2
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issue 1
16-33
EN
An autoclave hypercritical drying procedure has been used to prepare precursors of MgO from Mg(OCH3)2. This material was prepared with a specific surface area of 1200 m2 g 1. The dehydrated materials consisted of much smaller crystallites than conventionally prepared MgO and were free of OCH3 groups. The precursors and samples of magnesium oxide were taken for experimental evaluation of their reactivity with mustard. The largest percentage of the conversion mustard into non-toxic products after the elapse of the reaction was 77%.
6
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Influence of nanocrystalline structure and surface properties of TiO2thin films on the viability of L929 cells

88%
Osękowska M., Karuga-Kuźniewska E., Wojcieszak D., Mazur M., Poniedziałek A., Kaczmarek D., Szymonowicz M., Rybak Z.
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EN
In this work the physicochemical and biological properties of nanocrystalline TiO2 thin films were investigated. Thin films were prepared by magnetron sputtering method. Their properties were examined by X-ray diffraction, photoelectron spectroscopy, atomic force microscopy, optical transmission method and optical profiler. Moreover, surface wettability and scratch resistance were determined. It was found that as-deposited coatings were nanocrystalline and had TiO2-anatase structure, built from crystallites in size of 24 nm. The surface of the films was homogenous, composed of closely packed grains and hydrophilic. Due to nanocrystalline structure thin films exhibited good scratch resistance. The results were correlated to the biological activity (in vitro) of thin films. Morphological changes of mouse fibroblasts (L929 cell line) after contact with the surface of TiO2 films were evaluated with the use of a contrast-phase microscope, while their viability was tested by MTT colorimetric assay. The viability of cell line upon contact with the surface of nanocrystalline TiO2 film was comparable to the control sample. L929 cells had homogenous cytoplasm and were forming a confluent monofilm, while lysis and inhibition of cell growth was not observed. Moreover, the viability in contact with surface of examined films was high. This confirms non-cytotoxic effect of TiO2 film surface on mouse fibroblasts.
7
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CHARACTERISATION OF THIN CHITOSAN FILMS FOR GUIDED TISSUE REGENERATION PURPOSES

75%
Lewandowska K., Furtos G. F.
Progress on Chemistry and Application of Chitin and its Derivatives
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2017
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vol. 22
118-124
EN
The morphology and structure of thin films containing chitosan (Ch) with montmorillonite (MMT) were characterised by scanning electron microscopy (SEM), atomic force microscopy (AFM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Thin films of two chitosan samples and a composition of chitosan with montmorillonite were formed by casting methods from acetic acid solutions and were soaked in a simulated body fluid (SBF) solution at 37C for 14 days. The samples were compared before and after soaking. The obtained results showed growth of new phases containing calcium in all prepared films.
8
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SURFACE PROPERTIES OF CHITOSAN COMPOSITES WITH POLY(VINYL ALCOHOL) AND HYDROXYAPATITE

75%
Lewandowska K.
Progress on Chemistry and Application of Chitin and its Derivatives
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2015
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vol. 20
177-182
EN
Surface properties of composites containing chitosan (Ch), poly(vinyl alcohol) (PVA) with hydroxyapatite (HAP) were investigated by contact angle measurements and atomic force microscopy (AFM). Thin films of Ch/HAP and Ch/PVA/HAP composites have been formed by casting methods from acetic acid solutions. Measurements of the contact angle for diiodomethane (D), and glycerol (G) on the surface of chitosan films, Ch/HAP and chitosan/PVA/HAP films were made and surface free energy was calculated. It was found that chitosan/HAP or Ch/PVA/HAP blend surface is enriched in high surface energy component i.e. chitosan. The study of composites by AFM showed a completely different morphology when compared with unmodified components. The roughness of composites increase after the addition of hydroxyapatite. This may indicates a strong interaction between the polymeric components and inorganic additive.
9
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SURFACE PROPERTIES OF CHITOSAN ACETATE, POLYACRYLAMIDE AND THEIR MIXTURES

75%
Lewandowska K.
Progress on Chemistry and Application of Chitin and its Derivatives
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2013
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vol. 18
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issue 18
29-34
EN
The surface properties of chitosan acetate (ChA), polyacrylamide (PAM) and ChA/PAM mixtures have been investigated by the tapping-mode atomic force microscopy (AFM) and monitored by contact angle measurements. Chitosan is blended with polyacrylamide in acetic acid solution and this solution is cast to prepare the mixture film. Measurements of the contact angle for two different liquids (diiodomethane and glycerol) on the surface of chitosan acetate. The surface free energy (γs) as well as dispersive (gsd) and polar (gsp) components were calculated from contact angle values by Owens-Wendt methods using an appropriate computer program. The values of polar and dispersive components of surface free energy show that PAM films are more polar than chitosan acetate films. In the case of ChA/PAM mixtures, the values of surface free energy and polar component are reduced significantly compared with pure polymers. This behavior indicates rather hydrophobic character of this surface. The changes of topography images were considered by determining the root mean square (RMS) deviation in the image data. The study of blends by AFM showed a completely different morphology when compared with pure components. The roughness of blends increases with the increase of ChA content. This may indicates a strong interaction between the polymeric components.
10
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MISCIBILITY AND INTERACTIONS IN CHITOSAN AND POLYACRYLAMIDE MIXTURES

75%
Lewandowska K.
Progress on Chemistry and Application of Chitin and its Derivatives
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2014
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vol. 19
65-71
EN
In the present work, the results of Fourier transform infrared (FTIR) and atomic force microscopy (AFM) studies of films of chitosan acetate (ChA), polyacrylamide (PAM), and their mixtures are presented. The morphology of the ChA and PAM films and their mixtures was studied by tappingmode atomic force microscopy (AFM). The topography images were considered by determining the root mean square (RMS) deviation in the image data. The study of mixtures by AFM showed a completely different morphology when compared with pure components. The roughness of mixtures increases with the increase of ChA content but is significantly reduced after UV exposure. This may indicate a strong interaction between the polymeric components. The FTIR spectroscopy also supports the obtained results. The miscibility of polymer mixtures is related to interactions between the functional groups of the polymeric components.
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