Two-Ply Composite Membranes with Separation Layers from Chitosan and Sulfoethylcellulose on a Microporous Support Based on Poly(diphenylsulfone-N-phenylphthalimide)

Two-ply composite membranes with separation layers from chitosan and sulfoethylcellulose were developed on a microporous support based on poly(diphenylsulfone-N-phenylphthalimide) and investigated by use of X-ray diffraction and scanning electron microscopy methods. The pervaporation properties of the membranes were studied for the separation of aqueous alcohol (ethanol, propan-2-ol) mixtures of different compositions. When the mixtures to be separated consist of less than 15 wt % water in propan-2-ol, the membranes composed of polyelectrolytes with the same molar fraction of ionogenic groups (-NH3+ for chitosan and -SO3− for sulfoethylcellulose) show high permselectivity (the water content in the permeate was 100%). Factors affecting the structure of a non-porous layer of the polyelectrolyte complex formed on the substrate surface and the contribution of that complex to changes in the transport properties of membranes are discussed. The results indicate significant prospects for the use of chitosan and sulfoethylcellulose for the formation of highly selective pervaporation membranes

Bacterial Cellulose (Komagataeibacter rhaeticus) Biocomposites and Their Cytocompatibility

A series of novel polysaccharide-based biocomposites was obtained by impregnation of bacterial cellulose produced by Komagataeibacter rhaeticus (BC) with the solutions of negatively charged polysaccharides—hyaluronan (HA), sodium alginate (ALG), or κ-carrageenan (CAR)—and subsequently with positively charged chitosan (CS). The penetration of the polysaccharide solutions into the BC network and their interaction to form a polyelectrolyte complex changed the architecture of the BC network. The structure, morphology, and properties of the biocomposites depended on the type of impregnated anionic polysaccharides, and those polysaccharides in turn determined the nature of the interaction with CS. The porosity and swelling of the composites increased in the order: BC–ALG–CS > BC–HA–CS > BC–CAR–CS. The composites show higher biocompatibility with mesenchymal stem cells than the original BC sample, with the BC–ALG–CS composite showing the best characteristics

Floating layers and thin films of mesogenic mix-substituted phthalocyanine holmium complex

The supramolecular organization of the A$_3$B-type phthalocyanine holmium complex (A3B–Ho) was investigated in floating layers at the air–water interface and in Langmuir-Schaefer thin films at the air–solid interface. The floating layers formed under different experimental conditions on the water subphase using the Langmuir technique. They were studied by Brewster angle microscopy, grazing incidence X-ray diffraction and X-ray reflectometry. It was established that molecules of A$_3$B–Ho form stable ordered floating monolayer on the water surface. Experimental conditions required for this monolayer formation were determined as following: the initial degree of coating of the water surface was 18%, the compression rate of barriers was 6 cm$^2$/min and the surface pressure was 0.4 mN/m. Under these conditions a stable crystalline monolayer structure was obtained with an area per one molecule 3.9 nm2. It has a two-dimensional face-on packing with the intralayer period of 2.06 nm. The Langmuir-Schaefer thin film was obtained on the basis of the above mentioned monomolecular floating layer. The film possesses a single two-dimensional structure with the packing of the molecules parralel to the substrate surface that was revealed by electron diffraction. The lattice parameters of the monomolecular film were $a$ = 1.65 nm, $b$ = 1.92 nm, $\gamma_1$ = 75. It was shown that the film preserves the structure of the floating monolayer