Demet Karaca Balta

Molecular chirality and chain branching in chiral bent-core liquid crystals control the helical vs. heliconical twist, leading to the discovery of new low-birefringent and isotropic mesophases.

In this study, we developed a novel one-pot synthesis method to fabricate well-defined single-chain polymeric nanoparticles (SCNPs) integrated with interpenetrating polymer network (IPN) systems. The synthesis process involved an initial intramolecular crosslinking of poly(methyl methacrylate-co-glycidyl methacrylate) to form SCNP followed by intermolecular crosslinking to produce single-chain nanogel (SCNG) structures. In addition, the achieved single-chain polymeric nanoparticle was subsequently incorporated into an IPN structure through urethane bond formation and a Diels–Alder click reaction involving furfuryl methacrylate (FMA) and bismaleimide (BMI). The thermal properties, swelling behaviors, and morphologies of the resulting SCNP-IPN systems were investigated. This work presents a novel strategy that integrates the single-chain folding concept with IPN systems, providing a promising platform for the development of robust and functional polymeric materials with potential applications in advanced materials science.

Folding of azide functionalized polymer chains was obtained via the copper‐catalyzed azide alkyne cycloaddition (CuAAC) methodology using a light‐responsive crosslinker as the ‘click’ component. Subsequently, crosslinked junction points were combined with a photoinduced radical combination strategy to achieve more compact nanoparticles. The resultant folding particles possess smaller particle sizes and higher glass transition temperature values compared to their linear analogues. Fourier transform IR spectroscopy, SEC, DSC, dynamic light scattering, ¹ H NMR and TEM techniques were used for characterization. © 2020 Society of Chemical Industry

A straightforward method is described to achieve polymeric nanoparticles by double folding of single linear chains. The side chain functional polystyrene with controlled molecular weight is converted to pendant azide and benzophenone motifs via postmodification reactions. Resulting functionalized chains undergo intramolecular crosslinking upon ultraviolet (UV) illumination using simultaneous and subsequent pathways at a dilute concentration. Particle size of nanoparticles can be tuned by changing the degree of crosslinking using a second folding process. Obtained single and double collapsed chains indicate higher glass transition temperatures and lower hydrodynamic radii compared to their intermediates. To our knowledge, the combination of photoinduced azide crosslinking and radical coupling processes is the first attempt to prepare double folding single polymer chains.

Light‐responsive crosslinked structures were prepared by a straightforward quaternization strategy using chloride functional polystyrene copolymers and commercially available Michler's ketone with varying feed ratios. Resulting organogels demonstrated excellent solvent absorption and their swelling characteristics were altered by UV‐light irradiation. According to scanning electron microscope images, UV‐illuminated samples showed an obvious photodecomposition, which enhanced their solvent uptake capacity with increase of UV exposure. Additionally, release behavior of eosin Y as a model compound was determined by UV–vis and fluorescence spectrometers. Achieved photoactive gels were also employed as the reusable heterogeneous initiators for photoinduced free‐radical polymerization of methyl methacrylate. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1275–1282

The cover image is based on the Research Article Synthesis and characterization of POSS hybrid organogels using Menschutkin quaternization chemistry by Deniz Kilic et al. DOI: 10.1002/pi.5719. image

The present research describes a series of organic–inorganic hybrid gels based on polystyrene and polyhedral oligomeric silsesquioxanes (POSSs) prepared using free radical copolymerization and Menschutkin chemistry techniques. In the first step, poly(styrene‐co‐chloromethylstyrene) is readily achieved by thermally initiated radical copolymerization and the subsequently obtained copolymer reacts with diethanolamine functional POSS nanoparticles which are employed as the crosslinker. The resulting hybrid network possesses ionic moieties and inorganic POSS nanoparticles. The POSS‐containing hybrid gels exhibit excellent organic solvent absorption and show good mechanical behaviour. Gel containing 0.8 × 10⁻³ mmol of POSS(DEA)₈ (DEA, diethanolamine) reached the highest swelling ratio; hence, the corresponding gel can absorb organic solvent up to 20× its weight. The rate constant, coefficients and diffusional behaviour of hybrid organogels in organic solvent were examined as well. The organic solvent intake of the hybrid gel follows a non‐Fickian type diffusion. © 2018 Society of Chemical Industry