Novel 9,10-bis(phenylethynyl)anthracenes (BPEA's) 5 were prepared in high yields and purity. They were synthesized by a Pd-catalyzed Sonogashira coupling reaction. These compounds are typical intramolecular charge transfer compounds, which consist of the electron-rich anthracene moiety and an electron acceptor part. Their emissions are all in the red region with λ max ranging between 616-638 nm and they exhibit high fluorescent quantum efficiencies.
In this study, the photo-optical properties of the series of new 1H-pyrazolo[3,4-b]quinoline derivatives were investigated. Pyrazoloquinoline studies were conducted to explain the electroluminescent effect in organic LEDs. Absorption and photoluminescence spectra for the materials under consideration were examined, and quantum chemical calculations were made. Differential scanning calorimetric and thermogravimetric measurements were carried out for the manufactured materials. The phase situation of the materials was determined, and glassy transitions were detected for three of the investigated materials. Degradation temperatures were obtained. Single-layer luminescent diodes based on the ITO/PEDOT:PSS/active layer/Al scheme were fabricated. Current–voltage and brightness–voltage characteristics of the diodes were determined, ignition voltage was calculated, and electroluminescence types were determined.
We have used Molecular Dynamics simulations to obtain the monomer density profiles for real linear and ring polymer chains of 360 monomers length with different topological structures such as simple knots: 31, 61, 91, 10124, complex knots 313151 and twisted knots with n = 10 and n = 20 in a slit geometry of two parallel walls with one attractive and another repulsive surface. We have used Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) software to perform simulations with the Verlet integration algorithm. The interactions between monomers were simulated as Lennard-Jones 12-6 potential, for bonds we have used Finitely Extensible Nonlinear Elastic (FENE) potential and the interaction with the walls was taken into account via Lennard-Jones 9-3 potential. We observed that topologically complex polymers have lower monomer density profiles near the attractive wall, but at some distance in the direction to the repulsive wall this tendency changes to the opposite. We showed that most complex twisted knots have two maxima in narrow slits. In the wide slits we do not observe such relation for twisted knots at higher temperatures. These results are important for better understanding the nature of the depletion forces which arise in a slit geometry of two parallel walls with one attractive and one repulsive wall.
The calculations of the dimensionless layer monomer density profiles for a dilute solution of phantom ideal ring polymer chains and star polymers with f = 4 arms in a Θ-solvent confined in a slit geometry of two parallel walls with repulsive surfaces and for the mixed case of one repulsive and the other inert surface were performed. Furthermore, taking into account the Derjaguin approximation, the dimensionless layer monomer density profiles for phantom ideal ring polymer chains and star polymers immersed in a solution of big colloidal particles with different adsorbing or repelling properties with respect to polymers were calculated. The density-force relation for the above-mentioned cases was analyzed, and the universal amplitude ratio B was obtained. Taking into account the small sphere expansion allowed obtaining the monomer density profiles for a dilute solution of phantom ideal ring polymers immersed in a solution of small spherical particles, or nanoparticles of finite size, which are much smaller than the polymer size and the other characteristic mesoscopic length of the system. We performed molecular dynamics simulations of a dilute solution of linear, ring, and star-shaped polymers with N = 300, 300 (360), and 1201 (4 × 300 + 1-star polymer with four arms) beads accordingly. The obtained analytical and numerical results for phantom ring and star polymers are compared with the results for linear polymer chains in confined geometries.
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