Shuta Hara

Transparent PDLLA/silica hybrid films were prepared via a sol–gel process using organosilane-terminated PDLLA, and two structural motifs—graft-type and 3D-network hybrids—were systematically compared. Dynamic mechanical analysis (DMA) revealed that silica incorporation significantly restricted polymer chain mobility, increasing the onset temperature of the storage modulus from 33.9 °C for neat PDLLA to 41.5 °C and 50.3 °C for the 15 and 20 wt% graft-type hybrids, respectively. Thermogravimetric analysis (TGA) confirmed silica contents of 8.8–18.5 wt% and showed that the 10% weight-loss temperature increased by ~60 °C relative to neat PDLLA, with improvements primarily governed by silica content rather than hybrid topology. Small-angle X-ray scattering (SAXS) demonstrated uniform nanoscale dispersion with inter-domain distances of ~60–65 nm and no domain coarsening; combining these distances with the PDLLA end-to-end distance (R₀ ≈ 24–30 nm) yielded effective silica domain sizes of 30–35 nm. Porod analysis distinguished diffuse interfaces in graft-type hybrids from more correlated structures in network-type hybrids. Optically, the hybrids maintained high transparency (>90% at 400 nm) up to 18 wt% silica, while the Abbe number increased from 55 (neat PDLLA) to 73 (20 wt%). These findings provide quantitative insight into how nanoscale silica organization dictates thermomechanical, thermal, and optical behavior in PDLLA hybrids, extending the understanding established by earlier studies and supporting the continued development of PDLLA/silica hybrid materials.

Inorganic nanoparticles (NPs) have significant potential for various applications; however, achieving stable dispersion in organic media and polymers remains a key challenge for their industrial use. We developed a novel dispersant, tributyl(3-((3,4-dihydroxyphenylamino)-3-oxopropyl)phosphonium chloride) (TPC), which contains a catechol group for strong NPs binding and a phosphonium chloride moiety for effective dispersion. The versatility of TPC was demonstrated by stabilizing TiO₂, Fe₂O₃, and ZnO NPs in methanol using bead milling, as confirmed by TGA, DLS, zeta potential, and TEM analyses. In addition, TPC exhibited broad compatibility across solvents with varying dielectric constants. Furthermore, several hybrid polymer films were prepared by casting and photosolidification from monomers to assess their dispersibility and TPC−polymer matrix interactions, using Cole–Cole plots. Notably, poly(D,L-lactic acid) hybrid films retained their dispersion stability after recycling, highlighting the sustainability of TPC-coated NPs for material design. This study presents the first integration of phosphonium cations with catechol groups as dispersants, offering not only a breakthrough approach for developing nanocomposite materials with superior stability and performance, but also establishing a versatile platform concept that introduces a new design principle for universal and sustainable dispersant development across diverse nanomaterials and polymer systems.

Calcified tissues in living organisms, such as bone, dentin, and enamel, often require surgical intervention for treatment. However, advances in regenerative medicine have increased the demand for materials to assist in regenerating these tissues. Among the various forms of calcium phosphate (CaP), tricalcium phosphate (TCP)—particularly its α-TCP form—stands out due to its high solubility and efficient calcium release, making it a promising candidate for bone regeneration applications. Nevertheless, its rapid dissolution rate presents challenges when used as a reinforcing agent. In this study, we developed a hybrid material composed of poly(malic acid) (PMA) and α-TCP to achieve controlled calcium release while maintaining mechanical strength. The hybrid materials were prepared using a compression molding method optimized to suppress the hydrolysis of PMA. The bond between the carboxyl group of PMA and α-TCP was confirmed through infrared (IR) spectroscopy. A calcium release test demonstrated that the interaction between PMA and α-TCP extends the dissolution period of both components. These findings indicate that PMA/α-TCP hybrid materials have significant potential for applications in bone tissue engineering.

In this study, we developed a double-network hybrid polymer that controls the strength and density of cross-linking points by utilizing the bonds of titania and catechol groups with an o-nitrobenzyl group (ONBg) as the photoreactive cross-linking points. In addition, this hybrid material system, which is composed of thermally dissociable bonds between titania and carboxyl groups, can be molded before light irradiation. The Young's modulus increased by approximately 1000 times upon irradiation with UV light. Moreover, introducing microstructures using the photolithography technique improved the tensile strength and fracture energy by approximately 32 and 15 times, respectively, compared to the sample without the photoreaction. The improved toughness was achieved by the macrostructures, which enhanced the effective cleavage of sacrificial bonds between the carboxyl groups and titania.

Organic–inorganic hybrid materials have become indispensable high-performance and highly functional materials. This is owing to the improved dispersion control in hybrid materials and emergence of functional ionic liquids. Harmonization of both these factors has enabled the utilization of functional 3D network structures and nanodispersions in composite materials. Polymeric materials endow materials with flexibility, toughness, and shape-memory properties, whereas inorganic materials provide materials with unique optical, electrical, and magnetic properties due to their nanosize. Organic–inorganic hybrid materials have evolved into novel materials that go beyond the composite rule. In this review, the historical development of hybrid materials prepared using the sol-gel method and the birth of ionic liquids have been summarized. In addition, the historical results leading to the development of functional 3D network structures and dispersion control have also been presented, as well as a review of the research on functional ionic liquids, which are of current interest. The authors also summarize the results of their research on functional ionic liquids. The design of new organic–inorganic hybrid materials has been discussed and the future prospects of new polymer composite materials provided.

FeCl₃ in the polymer matrix can be partially ordered using photolithography. Ordered FeCl₃ has improved magnetic susceptibility.