Stepan Podzimek

Poly(lactide-co-glycolide) (PLGA) derivatives are widely used in pharmaceutics as drug carriers owing to their biocompatibility, biodegradability, and tunable drug release profiles. This study investigates the impact of macromolecular branching on the molecular structure and physicochemical properties of PLGA. Linear PLGA and PLGAs star-branched on dipentaerythritol, tartaric acid, and ethylenediaminetetraacetic acid across core loadings of 2%, 4%, 8%, and 12% were synthesized by polycondensation and characterized using differential scanning calorimetry and size-exclusion chromatography with multi-angle light scattering. Dipentaerythritol and tartaric acid promoted effective star formation, systematically depressing both the glass transition temperature and the branching ratio (g'), whereas ethylenediaminetetraacetic acid exhibited restricted core reactivity due to steric hindrance, yielding properties resembling linear PLGA. Complementary Raman and Fourier-transform infrared spectroscopy of dipentaerythritol-branched PLGAs revealed concentration-dependent hydrogen bonding between terminal hydroxyl end-groups and backbone ester carbonyls, with specific Raman band area ratios (B1:2 and B4:3) systematically reflecting core loading. These spectral changes closely mirrored the reduction in g', demonstrating excellent agreement with the structural and thermal trends determined by the reference methods. Crucially, the direct correlation between local vibrational modes and macromolecular architecture establishes Raman spectroscopy as a promising, rapid, and reliable method for characterizing star-branched polymers and estimating their degree of branching.

The covalent integration of molecular fluorophores into polymer matrices is an attractive strategy for transferring efficient molecular emission into processable solid-state materials while reducing chromophore migration, aggregation, and phase separation. Herein, we report a series of three divinyl-functionalized phenanthro[9,10-d]imidazole emitters, PIm-DN-DV, PIm-OMeF-DV, and PIm-PyF-DV, designed to elucidate the influence of donor architecture on both molecular and polymer-integrated photophysics. The monomers were synthesized through modular Debus-Radziszewski condensation and palladium-catalysed Buchwald-Hartwig coupling, followed by incorporation of terminal vinyl groups enabling radical copolymerization with N-vinylcarbazole. DFT calculations and cyclic voltammetry revealed systematic donor-controlled stabilization of the HOMO level, with HOMO(CV) values shifting from -5.18 eV for PIm-DN-DV to -5.32 and -5.42 eV for the fluorene-containing PIm-OMeF-DV and PIm-PyF-DV derivatives, respectively. In solution, the final monomers display blue-green emission with PLQY values increasing from 43.3% for PIm-DN-DV to 70.6% and 90.1% for PIm-OMeF-DV and PIm-PyF-DV. Upon copolymerization with N-vinylcarbazole, the resulting VK-based films exhibit matrix-defined absorption but retain donor-dependent violet-to-blue emission. Notably, the fluorene-containing copolymer films exhibit highly efficient solid-state photoluminescence with PLQY values of 90.8% and 92.4%, accompanied by fast nanosecond decay dynamics. These results demonstrate that divinyl-functionalized phenanthroimidazoles are versatile polymerizable emitters and that covalent embedding into a carbazole-rich matrix provides an efficient route to bright donor-tunable emissive films.

Thiophene-tuned vinyl phenanthroimidazoles deliver predictable blue emission and copolymerize with PVK to form homogeneous, stable luminescent films without aggregation quenching.

Herein, we report the synthesis of a systematic series of stannaboroxine-based compounds and demonstrate their use as precursors for hydrophobic thin layers.

The paper provides an overview of possibilities and limitations of the characterization of long‐chain branching of polymers using multi‐angle light scattering (MALS) in batch mode, coupled to size exclusion chromatography (SEC) or asymmetric flow field flow fractionation (AF4), and in combination with viscometry of dilute polymer solutions. The application of particular methods is demonstrated on several branched polymers. The molar mass dependence of the draining parameter recently reported for star‐like polymer is confirmed for randomly branched polymer. The inconsistency of the number of arms in star polymers and the number of branch units in randomly branched polymers calculated using various theoretical equations is pointed out.

The presented study describes the coordination variability of non-symmetric ligand L ( L = 2-(C(Me)=N(C ₆ H ₃ -2,6-iPr ₂ ))-6-((iPrO) ₂ P=O)C ₅ H ₃ N) towards of different main-group halides.

The reaction of organogallium amide LGa(NEt2)2 (1) and organotin carbonate L(Ph)SnCO3 (2), where L = 2,6‐(Me2NCH2)2C6H3, with organoboronic acids RB(OH)2 yielded molecular gallium‐ and stannaboroxines LM(O3B2R2) (3–8) (3: M = Ga, R = 4‐tBu‐C6H4; 4: M = Ga, R = 4‐CF3‐C6H4; 5: M = Ga, R = 3,5‐(CF3)2‐C6H3; 6: M = PhSn, R = 4‐tBu‐C6H4; 7: M = PhSn, R = 4‐CF3‐C6H4; 8: M = PhSn, R = 3,5‐(CF3)2‐C6H3). The Lewis acidity of boron atom (especially in 8) allowed to form N → B coordination bond with bases such as 4‐Me2N‐pyridine (DMAP) or poly(4‐vinylpyridine‐co‐styrene) (PVPS) yielding new compounds DMAP→8 (9) and PVPS→8 (10). The good film forming properties of 10 allowed the deposition of transparent thin layers by spin‐coating method and the determination of their hydrophobic properties by the sessile drop method. The study of hydrophobicity was subsequently focused on the content of stannaboroxine 8 in PVPS and on the concentration influence of the deposited PVPS:8 mixture solution. The parameters of thin layers such as thickness, transparency, and roughness were also determined.