Note

The dynamic and structural properties of the water molecules in 3-(1-piperazinyl)-1,2-propanediol-containing polyvinyl alcohol membranes were analyzed by molecular dynamics simulations. The resulting curve of the coordination number with diffusivity yielded important insights into the changes in the state of the water molecules with the water content, clarifying a key factor in determining the membrane performance for CO₂ separation.

For the first time, this paper revealed that 2-picoline borane (pic-BH₃) functioned well in the reductive amination of chitosan. Therefore, N-benzyl chitosan with a nearly perfect degree of substitution was successfully obtained, which has rarely been achieved by other synthetic methods. The new method herein has many advantages, including being more facile, more efficient, and less harmful than conventional methods; thus, this method is applicable to other aldehydes or ketones, leading to a wide variety of N-modified chitosan specimens with desirable degrees of substitution in the future.

This study developed a novel method for the control of the cellulose crystal of cellulose I and II. The crystal transition from cellulose I to II was tracked when cellulose I, which is soaked in a low-concentration NaOH aqueous solution, was quenched using liquid nitrogen. The crystal transition progressed from the surface to the center of the sample. This quench treatment has the potential to fabricate new cellulose materials with a cellulose I core and a cellulose II surface.

The Suzuki–Miyaura coupling reaction of BrC₆H₄-SiRR’-C₆H₄Br 1 with phenylboronic acid 3 in the presence of ^tBu₃PPd precatalyst 4 and CsF/18-crown-6 produced a phenyl-disubstituted product, indicating that the Pd catalyst underwent catalyst transfer on the silylene group. The polycondensation of 1 and phenylenediboronic acid 2 yielded cyclic polymers even when excess 1 was used. The obtained cyclic polymers containing the silylene group showed stronger fluorescence in solution than did the methylene counterpart.

The surface properties of the star polymer coating were evaluated with their resistance to protein adsorption and surface zeta (ζ)-potential to clarify the mechanism for inhibition of cell adhesion. The surface of the star polymer coating with a high density of poly(2-hydroxyethyl methacrylate) formed an electrically neutral diffuse brush structure in water and showed high resistance to protein adsorption. Considering the data obtained in the study, the surface ζ-potential and antibiofouling properties were correlated by controlling the molecular architecture of the coating material.

Surface amino groups (SAGs) on nanochitin materials were quantified using three amino-labeling reagents and two cationic dyes. After binding to SAGs, the excess labeling reagents or generated molecules were assessed by spectrophotometry. The dyes were adsorbed onto SAGs, and the excess was similarly quantified. The obtained values were compared with the titration values. Although the values by labeling reagents were underestimated, some of the values were proportional to those by titration. Reliable results were attained using the two labeling reagents with conversion equations or using Acid Orange 7 adsorption.

The morphology and physical properties of polyisoprene ionomers co-neutralized with Na⁺ and Mg²⁺ in different ratios have been studied. The mechanical and self-healing properties of the ionomer were reinforced and disturbed, respectively, at over 25 % of the Mg²⁺ ratio, where linkage via Mg²⁺ in the network is pervasive throughout the material.

We report the humidity-responsive volume changes of a poly(N-isopropylacrylamide) (PNIPAAm) gel and bending deformation of a PNIPAAm and poly(N,N-dimethylacrylamide) (PDMAAm) complex gel.

To develop a novel gel catalyst system for a selective reaction, we prepared a variety of gels with homogeneously dispersed crosslinked domain (CD) structures containing iridium complexes with various crosslinking densities. The designed CD gel catalyst catalyzed the N-alkylation of aniline with benzyl alcohol, and the steric effect of the CD structure allowed the selective formation of the secondary amine product by controlling the access of the substrate to the iridium complex.

We determined intrinsic viscosity for polystyrene (PS) samples with a wide range of molecular weight in d-limonene, which attracts interest as an environmentally friendly solvent for PS. By analyzing the experimental data obtained in d-limonene using the helical wormlike chain model with and without the excluded-volume effect, solvent quality of d-limonene for PS was quantitatively evaluated. Consequently, it was concluded that d-limonene belongs to the category of medium solvent, which is intermediate between good solvents like toluene and poor solvents like cyclohexane, for PS.

Narrow size distributions of spherical polyacrylic acid (PAA) particles are produced through precipitation polymerization without the need for stabilizers or emulsifiers. In this study, we employed small-angle X-ray scattering (SAXS) to investigate the polydispersity index (PDI) associated with the molecular weight distribution of the particles. By fitting the SAXS profiles, we were able to determine particle sizes, standard deviation, and the PDI with high precision. Our findings from SAXS confirmed that the PAA particles are monodisperse, both statistically and quantitatively, with a PDI of less than 1.05.

The isothermal crystallization behaviors of blends of cyclic polyethylene (C-PE) and linear polyethylene (L-PE) in a quiescent state were investigated. This figure shows the inverse of the half-crystallization time (1/t_1/2) as a function of the weight fraction of L-PE (Φ_L-PE) at different degrees of supercooling (ΔT). The 1/t_1/2 showed a minimum at Φ_L-PE = 30–40 wt%, irrespective of ΔT. By considering the experimental relationship between 1/t_1/2 and Φ_L-PE, we speculated that the suppression of crystallization in the blended system was caused by a novel entanglement formed by the penetration of the L-PE chain into the C-PE chain.

In this research, we reported a novel and simple approach to using tetramethylthiuram disulfide (TMTD) to prepare self-healing vulcanized natural rubber. TMTD as a sulfur donor and accelerator was used with different contents, ranging from 1.0 to 3.0 phr, to vulcanize high ammonia natural rubber (HANR). The best self-healing performance, i.e., 50–60% stress recovery and 80–95% strain recovery, was achieved for vulcanized natural rubber samples with 1.5 to 2.0 phr loading of TMTD. This approach discovered the potential application of TMTD in preparing self-healing vulcanized natural rubber.

In this paper, the construction of a hierarchical supramolecular structure comprising reduction-responsive DNA microspheres and semi-artificial glycopeptide-based micro-asters was described. Such a unique hierarchical supramolecular structure was obtained through molecular assembly of three oligonucleotides and a semi-artificial glycopeptide in a single thermal annealing process under aqueous conditions in the presence of Mg²⁺.

Atomic molecular dynamics simulations of the complexation of plasmid DNA in the presence of two types of cationic peptides clear the mechanism of plasmid DNA condensation for gene delivery systems.

Quantifying the interfacial energy of a polymer–liquid interface is challenging. We previously succeeded in analyzing the interfacial energy of a dynamic polymer brush interface by measuring the deformation of an ultrathin elastomer film floating on water. However, the quantitativity remains debatable because the bulk modulus was used. In this study, we reanalyze the interfacial energy using the ultrathin-film modulus. Large negative interfacial energy was observed for the system of high-density stretched brushes. The free energy balance for the system floating on water was calculated, validating the negative interfacial energy.

Two types of polyimide nanofibers (PINFs) were prepared. PINF-I (lengths = 305 ± 152 nm and diameters = 12 ± 2 nm) was prepared via crystallization of PI dissolved in a concentrated sulfuric acid solution. Adding t-butanol to a PINF-I aqueous dispersion and subsequent freeze–drying produced PINF-II (diameters = 105 ± 99 nm) with PINF-I aggregated into a fibrous form. The PI crystalline unit cell parameters were orthorhombic, a = 1.21 nm, b = 0.88 nm, and c = 2.23 nm (molecular chain axis direction).

PVDF forms β- and γ-phases in the presence of alkylammonium salts. We investigated crystal polymorphism obtained by various crystallization processes using FT-IR in PVDF added with two different alkylammonium salts. The fractions of crystalline phase changed with crystallization processes and ionic salts, which is attributed to the different crystallization mechanisms depending on the strengths of the ion-dipole interactions between alkylammonium salts and PVDF chains.

A PS/silica hybrid nanomatrix was formed by graft copolymerization of first styrene and then VTES onto NR particles in the latex stage. This hybrid nanomatrix structure was composed of nanosilica with a size of less than 100 nm and PS, which resulted in outstanding mechanical and viscoelastic properties. The superior properties of the hybrid nanomatrix were due to the synergetic effect of PS and nanosilica. The morphology and mechanical properties of the hybrid nanomatrix were maintained after acetone extraction, whereas they were distorted and reduced, respectively, after annealing

Polytetrafluoroethylene (PTFE) has widely been used in essential daily items and biomedical materials. The application range of PTFE should be greatly expanded if it can be flexibly functionalized. However, the functionalization method is still limited. In this study, peptides with affinity to PTFE were identified through affinity-based selection from a phage-displayed peptide library. The peptides had potential as a molecular glue to immobilize functional proteins and biomolecular assemblies, i.e., phages, onto PTFE films.