New Principles of Polymer Composite Preparation. MQ Copolymers as an Active Molecular Filler for Polydimethylsiloxane Rubbers

Colorless transparent vulcanizates of silicone elastomers were prepared by mixing the components in a common solvent followed by solvent removal. We studied the correlation between the mechanical behavior of polydimethylsiloxane (PDMS)-rubber compositions prepared using MQ (mono-(M) and tetra-(Q) functional siloxane) copolymers with different ratios of M and Q parts as a molecular filler. The composition and molecular structure of the original rubber, MQ copolymers, and carboxyl-containing PDMS oligomers were also investigated. The simplicity of the preparation of the compositions, high strength and elongation at break, and their variability within a wide range allows us to consider silicone elastomers as a promising alternative to silicone materials prepared by traditional methods

Improving the Efficiency of Organic Solar Cells via the Molecular Engineering of Simple Fused Non-Fullerene Acceptors

The development of novel non-fullerene small-molecule acceptors (NFAs) with a simple chemical structure for high-performance organic solar cells (OSCs) remains an urgent research challenge to enable their upscaling and commercialization. In this work, we report on the synthesis and comprehensive investigation of two new acceptor molecules (BTPT-OD and BTPT-4F-OD), which have one of the simplest fused structures among the Y series of NFAs, along with the medium energy bandgap (1.85 eV–1.94 eV) and strong absorption in the visible and near-IR spectral range (700–950 nm). The novel NFAs have high thermal stability, good solubility combined with a high degree of crystallinity, and deep-lying levels of the lowest unoccupied molecular orbital (up to −3.94 eV). The BTPT-OD with indan-1-one-3-dicyanvinyl terminal acceptor group is superior to its counterpart BTPT-4F-OD with 5,6-difluorindan-1-one-3-dicyanvinyl group both in the number of synthetic steps and in the photovoltaic performance in OSCs. PM6:BTPT-OD systems exhibit superior photovoltaic performance due to the higher charge mobility and degree of photoresponsiveness, faster carrier extraction, and longer carrier lifetime. As a result, BTPT-OD has almost two times higher photovoltaic performance with PM6 as a donor material due to the higher JSC and FF than BTPT-4F-OD systems. The results obtained indicate that further development of OSCs can be well achieved through a rational molecular design

Effect of Composition and Molecular Structure of Poly( l -lactic acid)/Poly(ethylene oxide) Block Copolymers on Micellar Morphology in Aqueous Solution

The effect of the hydrophobic block length in diblock (PLLA$_x$-b-PEO$_{113}$, x = 64, 166, 418) and triblock (PLLA$_y$-b-PEO$_{91}$-b-PLLA$_y$, y = 30, 52, 120) copolymers of l-lactic acid and ethylene oxide on the structure of micelles prepared by dialysis was studied by wide- and small-angle X-ray scattering in dilute aqueous solution, dynamic light scattering, transmission electron microscopy, atomic force microscopy, and force spectroscopy. It was found that the size of the crystalline PLLA core is weakly dependent on the PLLA block length. In addition to individual micelles, a number of their micellar clusters were detected with characteristic distance between adjacent micelle cores decreasing with an increase in PLLA block length. This effect was explained by the change in the conformation of PEO chains forming the micellar corona because of their overcrowding. Force spectroscopy experiments also reveal a more stretched conformation of the PEO chains for the block copolymers with a shorter PLLA block. A model describing the structure of the individual micelles and their clusters was proposed