Chitosan is a promising environment friendly active polymer packaging material due to its biodegradability, exceptional film forming capacity, great mechanical strength, appropriate barrier property along with intrinsic antioxidant and antimicrobial features. Bifunctional reagent was used for producing water insoluble chitosan films. Biopolymeric films crosslinked by Genipin (Gp), which is a reagent of natural origin, should have high potential in food packaging. The influence of the ratio of functional groups in the chitosan-Gp system on film absorption in the visible and ultraviolet regions of the spectrum, sorption, physical, and mechanical properties of the films has been studied. The degree of chitosan crosslinking in the films obtained from solutions containing Gp was estimated using the experimental data on film swelling and water vapor sorption isotherms. It is demonstrated that crosslinking with genipin improves swelling, water resistance, and mechanical properties of the films.

Chitosan-g-oligolactide copolymers with relatively long oligolactide grafted chains of various stereochemical compositions have been synthetized via a solvent-free mechanochemical technique and tailored to fabricate three-dimensional hydrogels using two-photon induced microstereolithography. An effect of the characteristics of chitosan and oligolactide used for the synthesis on the grafting yield and copolymer’s behavior were evaluated using fractional analysis, FTIR-spectroscopy, dynamic light scattering, and UV-spectrophotometry. The lowest copolymer yield was found for the system based on chitosan with higher molecular weight, while the samples consisting of low-molecular weight chitosan showed higher grafting degrees, which were comparable in both the cases of l,l- or l,d-oligolactide grafting. The copolymer processability in the course of two-photon stereolithography was evaluated as a function of the copolymer’s characteristics and stereolithography conditions. The structure and mechanical properties of the model film samples and fabricated 3D hydrogels were studied using optical and scanning electron microscopy, as well as by using tensile and nanoindenter devices. The application of copolymer with oligo(l,d-lactide) side chains led to higher processability during two-photon stereolithography in terms of the response to the laser beam, reproduction of the digital model, and the mechanical properties of the fabricated hydrogels.

Synthesis and theoretical and experimental investigations of a novel nanostructured organosilicon luminophore (NOL) containing six 2,2′-bithienyl donor units connected via silicon atoms to a 1,4-bis(5-phenylthienyl-2-yl)-benzene acceptor unit with efficient intramolecular Förster resonance energy transfer are reported. The NOL shows a unique combination of optical properties: a high photoluminescence (PL) quantum yield of up to 91%, a fast PL decay time of down to 800 ps, a large pseudo-Stokes shift of 101 nm and a huge molar extinction coefficient of 1.4 × 10⁵ M⁻¹ cm⁻¹. These peculiarities caused by the specific arrangement of the donor and acceptor fragments at the nanoscale distance within the NOL were correlated with the molecular structure of the NOL using theoretical calculations, which for the first time allowed successful prediction of the oscillator strength, PL decay time and intramolecular energy transfer efficiency. A comparison of the photophysical properties of the NOL with the standard laser dye POPOP in THF and toluene solutions revealed its huge application potential in organic photonics and high energy physics.