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.

Organic luminophores are widely used in various optoelectronic devices, which serve for photonics, nuclear and particle physics, quantum electronics, medical diagnostics and many other fields of science and technology. Improving their spectral-luminescent characteristics for particular technical requirements of the devices is a challenging task. Here we show a new concept to universal solution of this problem by creation of nanostructured organosilicon luminophores (NOLs), which are a particular type of dendritic molecular antennas. They combine the best properties of organic luminophores and inorganic quantum dots: high absorption cross-section, excellent photoluminescence quantum yield, fast luminescence decay time and good processability. A NOL consists of two types of covalently bonded via silicon atoms organic luminophores with efficient Forster energy transfer between them. Using NOLs in plastic scintillators, widely utilized for radiation detection and in elementary particles discoveries, led to a breakthrough in their efficiency, which combines both high light output and fast decay time. Moreover, for the first time plastic scintillators, which emit light in the desired wavelength region ranging from 370 to 700[emsp14]nm, have been created. We anticipate further applications of NOLs as working elements of pulsed dye lasers in photonics, optoelectronics and as fluorescent labels in biology and medical diagnostics.

Owing to the combination of efficient charge transport and bright luminescence, thiophene–phenylene co-oligomers (TPCOs) are promising materials for organic light-emitting devices such as diodes, transistors and lasers. The synthetic flexibility of TPCOs enables facile tuning of their properties. In this study, we address the effect of various electron-donating and electron-withdrawing symmetric terminal substituents (fluorine, methyl, trifluoromethyl, methoxy, tert-butyl, and trimethylsilyl) on frontier orbitals, charge distribution, static polarizabilities, molecular vibrations, bandgaps and photoluminescence quantum yields of 5,5′-diphenyl-2,2′-bithiophene (PTTP). By combining DFT calculations with cyclic voltammetry and absorption, photoluminescence, and Raman spectroscopies, we show that symmetric terminal substitution tunes the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies of TPCOs within a range of ∼0.7 eV, shifts the frequencies of the vibrational modes associated with the phenyl rings, changes the photoluminescence quantum yield by about two-fold and slightly changes the bandgap by ∼0.1 eV. We demonstrate that these effects are governed by two factors: the Hammet constant of the substituents and their involvement in the π-conjugation/hyperconjugation described by the effective conjugation length of the substituted oligomer. A detailed picture underlying the effect of the terminal substituents on the electronic, vibrational and optical properties of TPCOs is presented. Overall, the unraveled relationships between the structure and the properties of the substituted PTTPs should facilitate a rational design of π-conjugated (co-)oligomers for efficient organic optoelectronic devices.