Volume 54 Issue 11, November 2022

Multiarmed cyclosiloxanes bearing terminal amine groups (D_n^A, n = 4, 5) were obtained via a photocatalytic thiol-ene reaction, with regioselectivities of β-adducts as high as 93% irrespective of the repeating unit number in the cyclosiloxane rings. Ketoenamine-linked hybrid networks using D₄^A and D₅^A as the starting monomers were successfully synthesized via a mild Schiff base reaction with 2,4,6-triformylphloroglucinol and demonstrated high thermal stability and the formation of nanoparticle assemblies.

Viscoelastic properties of comb-shaped ring (RC) polystyrenes with different branch chain lengths were investigated. Even for the RC sample with short branches, a plateau of the dynamic modulus G^*(ω) was observed, suggesting the intermolecular branch chain entanglement occurred. In the region between the plateau and terminal regions, G^*(ω) was observed with a weaker angular frequency dependence than the terminal relaxation. The G^*(ω) data were analyzed with two models: the comb-Rouse model, in which the structures of RC molecules are taken into account by graph theory, and the Milner-McLeish model for entangled star-shaped polymers.

The lithium halides; LiBr, LiCl, and LiI were well dispersed in the PMMA matrix. The pinning effects of the PMMA chains due to the addition of the salts were enhanced in the viscoelastic spectra with increasing as the anion sizes. Moreover, it was suggested from the Griffith Theory, the stress concentration around the salts in the PMMA matrix acts as the crack initiation.

Using interfacial-sensitive sum-frequency generation (SFG) spectroscopy, it was found that incorporation of bulky and polar maleic anhydride (MA) into polystyrene (PSt) chains in an alternating manner, forming an alternating copolymer of P(St-alt-MA), led to reductions in π-π and dipolar interactions at the air interface relative to those in the bulk and thus greater T_g confinement effect for the alternating copolymer. The results demonstrate the crucial impacts of interfacial interactions on polymer dynamics under confinement.

The polymer chain morphologies of poly(4-iodostyrene) (P4IS) adsorbed on gold nanoparticles (GNPs) inside a polystyrene matrix were visualized using annular dark-field scanning transmission electron microscopy. The P4IS polymer chains adsorbed on GNPs exhibited a unique morphology wherein 1–2 molecular layers of P4IS surrounded a GNP, and the rest of the P4IS was aggregated at the side of the GNP. Enthalpy gain for the surrounding layer via adsorption and entropy gain for the remaining polymer chains via aggregation was considered the reason why the morphology was preferred.

We demonstrate the preparation of composite vitrimer-like materials containing silica nanoparticles (SNPs), where the matrix is composed of polyacrylate-based polymers crosslinked via a pyridine–bromo quaternization reaction. The quaternized pyridine at the crosslinking point exchanges the bond pair via trans-N-alkylation at high temperatures. Thermal and mechanical investigations first reveal the formation of the bound rubber phase around the SNP, which eventually affects the relaxation behaviors at high temperatures. In the final section, some useful functions owing to the bond exchange nature, such as reprocessability and recyclability, are exhibited.

Hetero-telechelic poly(ethylene glycol)s that contain a hydroxy group and a maleimide-furan adduct their α and ω ends, respectively, were isolated as a novel type of hetero-telechelic polymers (HTPs) via the post-modification of commercially available hydroxy-terminated PEGs with furan-protected p-maleimidophenyl isocyanate and subsequent purification with reversed-phase column chromatography at critical conditions.

Covalent and hydrogen-bonding architectures were designed in polyisoprene (PI)-based rubber containing the conjugated poly[2,7-(9,9-dioctylfluorene)] (PF) to enable elastic and luminescent behavior with spontaneous healing features.

We report the nonradiative decay dynamics of charge transfer (CT) states generated in nonfullerene-acceptor-based polymer solar cells. The nonradiative decay rate constants k_nr decreased with an increase in the efficiency for dissociation of CT states into free carriers, indicating that nonradiative decay of CT states can be mitigated by increasing the delocalization of the CT state wave function.

Conducting polymer support with atomically dispersed metal centers for oxygen reduction and evolution reaction catalysis is a promising strategy to enhance the cyclability of Li–O₂ battery. We present a novel, reliable and highly efficient noble metal free polymer catalyst for Li air battery application. Novel cathode catalyst found to be very efficient for nearly 160 cycles with limiting the capacity to 500 mAh/g with relatively lower overpotential.

Nanosized keratin particles (Ker-DODAC) were prepared via the assembly of keratin chains with the aid of a cationic surfactant. The obtained nanoparticles (Ker-DODACss) possessed a hydrophobic core composed of surfactants. To modify its internal environment, cholesterol was loaded to nanoparticles. The obtained nanoparticles (Ker-DODACss-Chol) showed retention and release of payloads in response to multiple stimuli. Also, lipophilic antioxidants, α-tocopherol, was loaded to Ker-DODACss-Chol to prevent α-tocopherol from an oxidative degradation and to preserve the antioxidant activity.

The liquid-phase exfoliation of graphite is mass-producible and cost-effective method of graphene production. Polymers can be employed as dispersants to facilitate the exfoliation of graphite in organic solvents. We synthesized methacrylate polymers with various monomer ratios and molecular weights and investigated the efficient acquisition of graphene from graphite. Graphene with a uniform thickness was obtained when graphite was exfoliated using an optimized polymer dispersant.

The first ultrasoft aqueous lithium-ion batteries with coaxial fiber structures were fabricated with an all-hydrogel design. The all-hydrogel fiber aqueous Li-ion battery exhibited a high specific discharge capacity of 84.8 mAh·g⁻¹ and superior cycling behavior and rate capacity performance. A low Young’s modulus (e.g., 445 kPa) for the battery was achieved by making it entirely from hydrogels, which ensured mechanical compatibility with biological tissues.