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Wollastonite (W)/carbon black (CB)/chlorinated polyethylene (CPE) conductive composites were prepared via melt compounding using CB and wollastonite as fillers and CPE as the matrix. The results indicated that the room temperature resistivity of CPE/CB/wollastonite composites decreased to 1.66Ω·cm after 1 hour of heat treatment, and the PTC strength reached 4.7. Subsequently, the relationship between the internal structure of the materials, changes in crystallinity, and PTC properties was analyzed using X-ray diffractometry and DSC differential scanning calorimetry.

Photodynamic therapy using photosensitizers as therapeutic agents has various advantages such as high antitumor efficacy, spatiotemporal selectivity, and noninvasiveness. However, photosensitizers also accumulate in normal tissues as well as tumor tissues, causing side effects. Here, we report chlorophyll‒peptide conjugates as novel photosensitizers to decrease the side effect. The assembled conjugates are expected to exhibit tumor-selective accumulation and tumor-selective activation of phototoxicity.

Solid-state NMR with dynamic nuclear polarization (DNP-NMR) has recently attracted attention as a highly sensitive NMR measurement method for analyzing polymers. We recently investigated DNP-NMR for insoluble polymers, particularly cross-linked polymers, engineering plastics, and polymer-supported catalysts, and achieved high NMR signal sensitivity at a routinely accessible level. In this focus review, we present case studies on DNP-NMR measurements for a wide range of polymers.

This study examined how changing the water-glycerol solvent composition affects the self-healing and viscoelastic properties of self-healing gels, which have host-guest inclusion complexes as reversible crosslinks. Increasing glycerol concentration in the mixture solvent reduced hydrophobic interactions between β-cyclodextrin and adamantane, lowering the association constant of host-guest inclusion complexes. The weakened hydrophobic interaction hinders complex recombination and enhances the mobility of the network chains. Consequently, the enhancement of mobility improved the healing ratio because the interfacial diffusion of the chains was promoted at the repair interfaces.

Alternating π-conjugated copolymers containing 9,9-dialkylfluorene (Fl) units have been widely studied, but there are few of these copolymers with sp²-carbon functionalized Fl units. In this study, we expand this limitation by performing the anodic chlorination of alternating π-conjugated copolymers, which are composed of Fl and another arylene (Ar) (P(Fl-Ar)s), using an acetonitrile solution that contains aluminum chloride as an electrolyte. The sp²-carbon at the fluorene ring was successfully chlorinated by anodic chlorination. P(Fl-Ar)s containing sp²-chlorinated fluorene units has different emission properties from the original P(Fl-Ar)s.

The peptide-Au nanoparticle (AuNP)-TiO₂ nanocomposite in which AuNPs were connected by TiO₂-coated conductive peptide nanowire was acted as effective VOC sensor.

Functional dyes offer fascinating properties in response to external stimuli and enable unique stimuli-responsive functions in materials by chemical incorporation into polymers. In this review, we highlight our recent studies conducted in the last half decade on stimuli-responsive smart polymers and polymeric materials offering, for example, switchable adhesion, mechanical actuation, and chemical sensing based on functional dyes that are chemically incorporated into the structures, with a particular focus on the stimuli of light, force, electric fields, and chemicals including water.

The degree of gel-gel phase separation (GGPS) was compared using multi-arm poly(ethylene glycol) (PEG) hydrogels. GGPS can occur at c < c*, with 8-arm PEG exhibiting a stronger turbidity (D) indicating stronger GGPS compared to 4-arm PEG. This indicates that phase-separated PEG can be obtained at low concentrations simply by increasing the number of branches. Furthermore, phase-separated 8-arm PEG showed higher osteogenic differentiation in vitro.

Sodium alginate and carboxymethyl chitosan were used as raw materials, and the dynamic imine bonding network formed by the two was combined with the coordination bonding network formed by acrylic acid and aluminum ions. The dual-network structure of the hydrogel not only gives the hydrogel excellent self-healing properties, but also gives the hydrogel excellent mechanical properties, with a strain at break as high as 3787%. In addition, the hydrogel has the antibacterial property of inhibiting the growth of E. coli and S. aureus and good electrical conductivity.

Heat insulators are key materials for efficient energy use and reduction of CO₂ emissions. Recently, we examined cross-linked polymethylsilsesquioxane (MSQ) for use as the basic structure of heat-resistant insulation materials. In this study, we prepared MSQs with different cross-linking units and examined the effects of their structures on the heat resistance and heat insulation properties. Among those, MSQ linked by diethynylbenzene had sufficiently low thermal diffusivity and moderately high heat resistance.

In this study, branched polymers with different copolymerization composition ratios of α-chloro-ε-caprolactone (α-ClCL) and ε-caprolactone (ε-CL) were prepared using α-ClCL and trimethylolpropane as the initiator. Furthermore, acryloyl groups were introduced at each chain ends of branched polymer to form macromonomers capable of cross-linking reactions. Films obtained by photo-crosslinking macromonomers with chloro groups showed shape-memory properties. In addition, the chloro group introduced by α-ClCL was converted into an azide group. This film is expected to be applied to various functional surfaces through the click reaction in the future.

Physical modification of carbon materials using polymers is a useful technique for altering surface properties. The adsorption phenomenon of polybenzimidazole (PBI) in organic solvents onto different carbon materials with different surface morphologies and chemical compositions was examined to assess the key parameter controlling the adsorption phenomena. Adsorption isotherm measurements revealed that the adsorption of PBI was irreversible and thermodynamically favourable when interaction between solvent-carbon or PBI-solvent is low. PBI did not diffuse into micropore and the coverage ratio of the PBI onto mesopore and macropore surface was around 60%.

A novel electrochemically stable composite polymer electrolyte (CPE) containing a lignin derivative and dilignol was exploited for battery application for the first time. The lignin derivatives improved both the ionic conductivity and mechanical performance of the polymer-based electrolytes. Notably, the LiFePO₄/Li cell had improved stability and recovery capacity, and the Coulombic efficiency was approximately 100%, with a capacity of more than 150 mAh g⁻¹. The resulting alterations in the coordination number led to enhanced Li⁺ mobility and consequently, increased conductivity and cell capacity.

This work shows that the length of flexible spacers in azobenzene (Azo)-based polymers is crucial for achieving room-temperature photoliquefaction (i.e., UV light-induced solid‒liquid phase transition). By adjusting the length of dithiol-functionalized flexible spacers, the melting temperature (T_m) of Azo polymers can be effectively modulated. Incorporating longer spacers decreases the T_m to a temperature achievable by the photothermal effect of Azo molecules, thus enabling photoliquefaction of Azo polymers at room temperature.

High performance polymer alloy films with high T_g, heat resistance, and sufficient toughness were prepared by blending a polyfunctional benzoxazine monomer (OP-p) and 4,4′-bismaleimidodiphenylmethane (BMI; 10–90 wt.%), followed by thermal curing up to 240 °C. The T_g increased to 228 °C and 329 °C for the polymer alloy films with BMI contents of 60 wt.% and 75 wt.%, respectively, which were higher than those of the POP-p or PBMI homopolymer. Despite the improvement in the T_g, the alloy films exhibited sufficient toughness as evidenced via the tensile test.

Dual thermoresponsive diblock copolymers comprising poly(di(ethylene glycol) ethyl ether acrylate) (PeDEGA) and poly(N-isopropylacrylamide) (PNIPAM) blocks with different lower critical solution temperatures (LCST_A and LCST_B) were prepared via organotellurium-mediated living radical polymerization. The LCST_A of the PeDEGA was lower than the LCST_B of PNIPAM. At T < LCST_A, the diblock copolymers dissolve in a unimer state. When the LCST_A ≤ T < LCST_B, polymer micelles with a PeDEGA core and PNIPAM shells formed. Above the LCST_B, intermicellar aggregates formed owing to hydrophobic interactions between the PNIPAM shells.

The graphical abstract shows the controlled radical polymerization of axially chiral monomers bearing a 1,1′-bi-2-naphthol (BINOL) skeleton. The evident increase in magnitude and opposite deflection direction of the specific optical rotation between the synthesized polymer and the monomer confirms the synthesis of the chiral polymers with specific structures.

An ionic electroactive polymer actuator (IEPA) was fabricated using regioregular-poly(3-hexylthiophene) (RR-P3HT) nanofibers. The RR-P3HT nanofiber mat was reinforced with regiorandom-P3HT (RRa-P3HT) as the tie chains and polybutadiene rubber (PBR) as a flexible matrix. The blended actuator, which preserved the RR-P3HT nanofiber structure, exhibited a substantial bending angle exceeding 80° after the redox reaction while sustaining reversible actuation for more than 30 cycles. The RR-P3HT nanofibers that were blended with RRa-P3HT and PBR demonstrated remarkable functionality as an IEPA, characterized by a significant bending angle and enduring cyclic actuation capabilities.

A series of divalent vinyl ketones containing fluorene backbone were synthesized via Friedel-Crafts acylation and subsequent elimination reactions. The divalent vinyl ketones underwent polyaddition with dithiols to yield the corresponding polysulfide via thiol–ene click chemistry. They also exhibited high reactivity in the Baylis-Hillman reaction with formaldehyde to afford a diol monomer, and the polycondensation with isophthaloyl dichloride yielded a poly(conjugated-ketone ester).

Phosphine sulfide (P=S) group-containing aromatic poly(ether)s with aliphatic substituents on the phosphorus atoms were developed for use as low dielectric materials, taking advantage of the low polarity of the P=S groups and the less polarizable nature of the aliphatic moieties. These polymers exhibited low dielectric constants (ε = 2.64–2.68 at 10 GHz and 2.56–2.59 at 20 GHz) and low dielectric dissipation factors (tanδ = 0.0034–0.0035 at 10 GHz and 0.0036–0.0037 at 20 GHz).