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Hydroxy-tethered platinum(II) complexes were synthesized and used as diol monomers for polyurethane synthesis. Polyurethanes with moderate molecular weights were obtained by conventional polyaddition with a diisocyanate. The polyurethane containing the platinum(II) complex substituted with t-Bu groups was soluble in common organic solvents, including CHCl3 and tetrahydrofuran. The obtained polyurethane exhibited distinguishable photoluminescence changes upon grinding in the solid state.
Strain-promoted azide-alkyne cycloaddition provides a facile and efficient approach for the modular construction of main-chain polymers comprised of nanosized building blocks.
The flow-induced crystallization behavior of high-density polyethylene (HDPE) was investigated using Rheo-Raman spectroscopy. Although crystallization did not progress at 128 °C without shear flow, the formation of short and long consecutive trans chains was enhanced by applying shear flow, which resulted in an increased crystallization rate. In particular, by increasing the shear rate or shear-flow time, the fraction of long consecutive trans chains drastically increased prior to crystallization, and oriented crystals formed. These results indicated that the shear rate and applied work were the important parameters dominating the formation of oriented crystals.
Polymer composites containing citric acid-modified cellulose (CAC) and hydrogen bonding moieties showed significant increases in mechanical toughness. In particular, an appropriate ratio of hydrogen bond donors and acceptors in the secondary linear polymer (poly(2-methoxyethyl acrylate)) maximized the toughness. The hydrogen bonds affected the phase. The maximum toughness was achieved for an amorphous structure without obvious phase separation.
The decomposition process of polystyrene particles dispersed in D2O was analyzed by in situ small-angle neutron scattering under near critical and supercritical conditions. Upon heating in the subcritical state, the particles were swollen by D2O because of enhanced miscibility between polystyrene and D2O. In the supercritical state, the particles were completely degraded and formed monomer- or oligomer-rich domains due to phase separation. The findings and utilized techniques provide essential knowledge about the ways to elucidate the structural change of plastics in sub- and supercritical fluids.
Polymers that can depolymerize into their constituent monomers are desirable sustainable materials, but demonstrations have focused on linear polymers. Here, a depolymerizable graft copolymer thermoplastic material is prepared by copolymerizing poly(L-lactide)-based and margaric acid-based trans-cyclobutane-fused trans-cyclooctene macromonomers. The two types of macromonomers are incorporated randomly. Proper thermal treatment is required to maximize, or even to observe, crystallinity in the microphase separated that persists over a range of temperature. The physical states of the soft and hard domains significantly impact the material’s tensile properties.
We investigated the effect of the hydrophobicity of the side chains of mixed-charge polymers on their interaction with cancer cell membranes. Six pH-responsive mixed-charge polymeric micelles consisting of cationic, anionic, and neutral moieties were created, with differences in hydrophobicity generated by altering the type of anionic monomer and the ratio of the hydrophobic spacer moiety. Evaluation of their affinity for cell membranes revealed that increases in the hydrophobicity and pH-responsive nature led to pH-selective toxicity, which was assumed to be caused by the disruption of cell membrane integrity.
Photoresponsive molecular amphiphiles have been incorporated into distinct soft materials to control properties in high temporal and high spatial manners. We demonstrate molecular azobenzene amphiphiles for construction of chiral supramolecular assemblies with excellent photoresponsibility and a high capacity for supramolecular transformation in aqueous media. Supramolecular chiral structures of azobenzene amphiphiles can assemble from microscopic to macroscopic length scales
The higher-order structures of polymer-brush-modified nanoparticles (PSiPs) in ionic liquids were analyzed using ultrasmall-angle X-ray scattering. The self-assembly of the PSiPs was entropy-driven. The transition threshold concentration of the PSiPs was understood through the Kirkwood–Alder transition by considering the effective particle sizes. The random hexagonal close-packed structure in the concentrated-polymer-brush regime exhibited the characteristics of hard spheres, whereas face-centered cubic and body-centered cubic structures in the semidilute-polymer-brush regime reflected softening of the interparticle potential.
This work presents a simple strategy to prepare 3D printable and tough ionogels that can adjust to arbitrary topography. Inks for direct ink writing were prepared by dispersing cellulose nanocrystals in an aqueous solution of polyvinyl alcohol. After printing, the ink underwent a freeze-thaw process to form soft and stretchable hydrogels. Further reshaping and solvent exchange with deep eutectic solvents led to geometrically complex and tough ionogels for wearable sensors.
We designed multiblock amphiphilic cyclophanes that possess twisted aromatic units with axial chirality. Electronic absorption and emission spectroscopy revealed that these cyclophanes are molecularly dispersed in organic solvents, while they form aggregates in aqueous environments. We also found that under aqueous conditions, the chiral aromatic units within homochiral cyclophanes adopt a more planar conformation compared to their diastereomer, demonstrating the possibility of stereoselective recognition. Furthermore, by comparing the corresponding multiblock amphiphiles that are linear and chiral, we found that the macrocyclic structure might be essential for recognition.
Inspired by mussel adhesion, polydopamine ultrathin films were formed at silicone oil/water interfaces even in neutral solutions. The MCF-7 cells successfully adhered to the oil/water interface without aggregation during cell growth. The interfacial wrinkles were induced by changes in the oil volume and the compressive stress, and the MCF-7 cells adhered to the oil/water interface and were arranged along the wrinkles. The polydopamine interfacial films provide new opportunities to investigate the relationships between toughness and patterns for tissue engineering and regenerative medicine.
