Reviews & Analysis

This article reviews the design, synthesis, and properties of 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers bearing phosphorylcholine groups, which mimic cell membrane surfaces to achieve biocompatibility and medical functionality. MPC polymer surfaces effectively suppress protein adsorption, cell adhesion, activation, and subsequent biological reactions. The practical approaches for implementing MPC polymers in medical devices are also described. Utilizing the unique bioinspired properties of MPC polymers, these devices have demonstrated remarkable performance in clinical use, significantly contributing to an improvement in patients’ quality of life.

In this review, we proposed a unique concept in which if the mobility of the adsorbed water around the proteins and the polymer is the same, protein adhesion will not occur, improving antithrombogenic properties. On the basis of the above concept, we have established the foundational technique for developing antithrombogenic materials and successfully achieved the world's first practical application of antithrombogenic PSf membrane artificial kidneys. The technique that enables polymer design led by computational science is applicable to various medical and diagnostic devices.

This Review highlights our development of highly efficient and selective palladium catalysts for direct arylation polymerization (DArP). P(2-MeOC₆H₄)₃ (L1) serves as a key supporting ligand that maintains reactive mononuclear Pd species. Coligands (TMEDA or XPhos) suppress side reactions and facilitate the activation of less reactive C–X bonds. Operating in polymer-solubilizing media (e.g., THF or toluene), these systems yield π-conjugated polymers with number-average molecular weights of up to 347,700 and cross-coupling selectivities of up to >99%; the resulting materials exhibit device-grade performance comparable to that of polymers prepared by conventional Stille coupling.

Artificial nanocelluloses are produced via the self-assembly of low-molecular-weight (LMW) cellulose in vitro and represent an emerging class of nanocelluloses developed over the past decade. Most artificial nanocelluloses reported to date are particulates. We have developed two types of nanostructured macroscopic materials through the self-assembly of LMW cellulose: nanoribbon network hydrogels and nanospiked microfibrous materials. This Focus Review summarizes our work along with related studies on these novel nanostructured cellulose materials.

This review delineates a design strategy for mechanoresponsive polymers by categorizing hydrogen-bonding (H-bonding) motifs into “rigid” and “flexible” types. Rigid H-bonds, with strong directionality, provide high elasticity and strength. In contrast, flexible H-bonds, such as aliphatic diols, possess multiple, conformationally diverse binding modes. This flexibility allows for more efficient energy dissipation and network recovery under strain, leading to materials with superior dynamicity. We discuss the intrinsic effects of structural flexibility of H-bonding groups on mechanical properties, independent of solvent interactions.

The selective capture of heavy metal ions is a major challenge due to the need for materials with high affinity, selectivity, and capacity. Nature uses proteins to manage metal ions via specific structural motifs. This focus review summarizes recent advances in bioinspired and biosynthetic integrated strategies for the capture of heavy metal ions. The topics discussed include (1) the structural and thermodynamic features of metal-binding proteins, (2) synthetic polymers that mimic the biological functions of proteins, and (3) hybrid materials that integrate biological (macro)molecules with synthetic polymers.

Time-resolved small-angle X-ray scattering (TR-SAXS) is crucial for real-time monitoring of soft matter kinetics, offering nanometer-to-micrometer structural insights and revealing complex kinetic pathways and mechanisms. This review highlights its power in understanding block copolymer self-assembly kinetics in solution, covering micelle formation driven by non-covalent interactions, polyelectrolyte complex micelles via electrostatic interactions, and polymerization-induced self-assembly (PISA).

Structural and steric restrictions in polymer chains resulted in significant differences between cyclic polymers and their linear counterparts in the interfacial properties. The topological influences on the air–water interfacial activity and aggregation behavior of PEG and Pluronic surfactants were investigated. Silver nanoparticles adsorbed with cyclic PEG exhibited high dispersion stability under physiological and various conditions. This study successfully combined the biocompatibility of PEG with the antibacterial activity of silver nanoparticles. These results demonstrate that utilizing polymer topology can serve as a useful tool for designing new functional materials.

Macromolecules with cyclic topologies exhibit unique structural properties, but synthesizing macrocyclic polymers—especially multicyclic ones—remains challenging. Our group has developed an efficient method to access multicyclic polymers without using cyclic precursors. This review highlights recent progress in the precise synthesis of multicyclic architectures, including cage-shaped, spiro-multicyclic, and graft polymers with cyclic or cage-like side chains, via intramolecular ring-opening metathesis oligomerization or cyclopolymerization of norbornenyl-functionalized macromonomers using Grubbs third-generation catalysts. Their fundamental properties and potential applications are also briefly summarized.

We present a revolutionary approach to enhance carbon fiber performance through advanced microstructure design and control, addressing limitations of size effects. Utilizing micromechanics, we engineered optimized microstructures and developed innovative techniques for their precise manipulation. Key to our success was the use of synchrotron radiation facilities for X-ray structural analysis, enabling hierarchical examination of single fibers. This led to ultrastrong carbon fibers with a 10% increase in tensile strength (7 GPa to 8 GPa). Our findings hold transformative potential for aerospace and energy applications requiring high-strength, lightweight materials.

Harnessing the plasmonic properties of gold nanorods (AuNRs) requires proper control of their arrangement and assembly. However, although the assembly of AuNRs into ordered structures has been achieved, active control over them remains challenging. The author and colleagues have developed methods to control the arrangement and assembly of AuNRs based on complex formation via electrostatic interactions with DNA, a polymer with unique properties, structure and excellent functionality. This Focus Review presents our work on the arrangement and assembly of AuNRs by DNA.

In this study, we developed starch-based films with tunable disintegration and dissolution rates in freshwater and seawater. The modified starch was mixed with oxidized cellulose or a water-soluble polymer to produce transparent, homogeneous films. Hydrogen bonding stabilized the films in freshwater, while in seawater, the hydrogen bond crosslinks dissociated, causing the film to dissolve rapidly. This technology offers a strategic balance between water resistance in everyday environments and controlled disintegration in marine conditions, presenting a sustainable alternative to petrochemical plastics with potential applications across various industrial sectors.

This paper reviews the degradation of polyesters and polycarbonates, including degradable aliphatic polymers. Organic catalysts enable efficient degradation and recycling of these condensation polymers, promoting a circular economy and reduction of waste and CO₂ emissions. Although super engineering plastics are difficult to recycle, recent studies show organocatalysts can facilitate their depolymerization and monomer recovery. Advances in monomer synthesis and controlled ring-opening polymerization allow for functional, sustainable, and degradable polymers. Moreover, side-chain engineering in aliphatic polymers enables controlled degradation. Future work should emphasize greener synthesis and comprehensive analysis of degradation impacts.

Ternary blend polymer solar cells incorporating near-IR materials are among the most promising approaches for effectively improving photovoltaic performance because they can extend the light-harvesting wavelength range and simultaneously improve charge transport. Here, we briefly review the progress in polymer solar cells and describe our recent studies on ternary blend polymer solar cells incorporating near-IR dye molecules. Of particular importance is the interfacial engineering for the placement of near-IR dye molecules at the donor/acceptor interface in ternary blend polymer solar cells.

An overview of the research on the melting kinetics of melt-grown folded-chain crystals (FCC) of polymers are provided, focusing particularly on the following aspects: (1) the thermodynamics; (2) Gibbs‒Thomson and Hoffman‒Weeks plots; (3) the unique kinetic barrier of FCC melting; (4) the results using a recently developed FSC with a chip sensor; (5) the exponential dependence of the melting rate on the degree of superheating, as determined from isothermal melting kinetics conducted using FSC; and (6) thermal Gibbs‒Thomson plots as an application of melting kinetics studies.

Emerging from DNA/RNA nanoengineering, synthetic nucleic-acid liquid condensates, forming via phase separation of nanostructures, have attracted increasing attention as a powerful platform for synthetic biology and molecular computing. Base-sequence specificity allows for molecular encoding for their organization, functions, and droplet interactions. Authors overview key topics of these programmable droplets, from dynamics programmability to numerical modeling. Additionally, this review highlights cross-linker modules, which enable dynamic compartmentalization and division of droplets triggered by specific molecular input. These modules allow the condensate phase behavior to represent Boolean logic operation.

A theoretical-computational scheme is formulated to analyze the shift in the aggregation equilibrium of a biomolecule upon addition of a cosolvent. The cosolvent-induced change in the solvation free energy plays the central role in the formulation, and it is shown for a model peptide that the ATP and urea cosolvents make the solvent environment more favorable for dissociated monomers than for aggregates. The effect of ATP to inhibit aggregation is brought by van der Waals interactions due to cancellation of the electrostatic effects between ATP and water.

Simple coacervates formed from low-molecular-weight molecules offer unique dynamic features, including stimulus-responsive phase transitions and reversible assembly/disassembly. This Focus Review highlights molecular design strategies, from historical perspectives to recent advancements. The sophisticated design of coacervates provides new opportunities in protocell models, biosensing, and drug delivery systems.

The production of silk in spiders and silkworms involves the transformation of concentrated liquid protein feedstock into hierarchically organized solid fibers through a highly controlled mechanism facilitated by their respective glandular spinning apparatus. Recent insights suggest that liquid–liquid phase separation (LLPS) plays a central role in organizing the initially disordered silk protein chains into dense yet dynamic condensates, which is a key step towards rapid fiber formation. This hierarchical assembly process underlies the remarkable mechanical properties of silk fibers.

This review highlights recent advances in engineering artificial enzyme condensates in vitro using charged polymers. Based on our recent findings, we describe strategies for designing condensates through interactions between polymers and enzymes or coenzymes. We then summarize enzyme activation mechanisms triggered by enzyme condensates, including size-dependent effects and conformational changes in enzymes. We also discuss potential applications and future directions, including multienzyme systems, integration with solid surfaces, and combination with rational enzyme design.