Thioether-functionalized polycarbonate nanosponges mitigate cisplatin-induced ototoxicity via ROS scavenging and cisplatin deactivation.

Single-particle techniques have the potential to measure the heterogeneous dynamics at the nanoscale within reaction mixtures. However, new tools are needed to gain insight into the molecular structure of evolving chemical systems at the single-particle level. Here, a single-particle method for measuring the density and mass of freely diffusing polymer nanoparticles is introduced and applied to the ring-opening metathesis polymerization of norbornene. Using 3D single-molecule active real-time tracking, growing polymer nanoparticles are tracked in situ, enabling simultaneous real-time measurement of both particle size and particle density. Particle density is extracted from the descent velocity of growing nanoparticles, giving insight into particle composition at the single-particle level. Using this technique, it is found that polynorbornene nanoparticles have a density of 850 ± 30 kg/m3, validated through control measurements on polystyrene beads. Density and size analysis indicate each nanoparticle contains ∼3.5 × 109 densely packed monomers, rather than loosely packed polymer chains. Simulations show that the accuracy of this method depends on particle size, the distance traveled before contact with the coverslip, solvent properties, and the number of trajectories. Overall, this paper presents a technique that enables in situ characterization of the density and mass of individual growing polymer nanoparticles.

Structural studies of N, O donor (imino)/(amino)pyridine mononuclear zinc(II) complexes as catalysts in the ring-opening polymerization reactions of rac-lactide

Diabetic wounds remain a major clinical challenge due to persistent inflammation and impaired tissue regeneration. In this study, we report the scalable synthesis of hyperbranched polyglycerol-b-poly(2-ethyl-2-oxazoline) star copolymers bearing terminal arginine groups (hPG-b-PEO-Arg), designed to self-assemble into nanoscale hydrocolloids (70-200nm) in aqueous media, driven by the distinct hydrophilicity of the polymer blocks. These hydrophilic nanoparticles penetrate damaged wound tissue, facilitating in vivo healing of diabetic wounds in rats (n=10). The copolymers were synthesized on a 300g scale via ring-opening polymerization and demonstrated excellent cytocompatibility with primary human fibroblasts and keratinocytes at concentrations up to 15mg/mL. In vivo, hPG-b-PEO-Arg treatment accelerated wound closure and promoted collagen-rich tissue regeneration without evidence of systemic toxicity, oxidative stress, or skin irritation. The combination of scalable synthesis, high biocompatibility, and intrinsic hydrocolloid-forming capability positions hPG-b-PEO-Arg as a promising platform for chronic wound management and broader biomedical applications.

Lewis acid-base pair catalysts for ring-opening polymerization of ε-caprolactone: 1,3-dialkylimidazole-2-chalcogenones and trimethyl aluminum

While the chemistry of ring-opening polymerization has advanced significantly to alleviate the escalating plastic waste crisis, highly selective and efficient catalysts to synthesize chemically recyclable, high-performance polythioesters remain needed. Typical ring-opening catalysts, however, face an intrinsic stereochemical challenge: unavoidable monomer racemization due to elevated α-hydrogen acidity, which severely hampers the synthesis of highly tactic crystalline materials and diminishes the performance of the resulting plastics. Here, we report the design and synthesis of a covalent borane-thiourea organocatalyst for the stereoselective ring-opening polymerization of enantiopure dithiolactones. Through incorporation of a strongly Lewis acidic 9-borafluorene moiety, this metal-free system effectively reduces the basicity of propagating thiolate chain ends while enabling thiourea-mediated monomer activation, thereby ensuring rapid polymerization with minimal racemization. Consequently, this approach affords polythioesters with near-perfect isotacticity (Pm=0.97) and high molecular weights (Mn up to 58.1kDa). Notably, the resulting stereoregular polymers are tough, semicrystalline materials with properties comparable to commercial polyolefins like low-density polyethylene, while exhibiting complete chemical recyclability to realize a sustainable cradle-to-cradle closed loop. Overall, this covalent borane-thiourea organocatalyst solves the intrinsic stereochemical challenges in typical ring-opening polymerizations, providing a powerful strategy to access chemically recyclable and tough thermoplastics from dithiolactones as promising next-generation sustainable polymers.

Incorporation of functional groups into poly(3-hydroxyalkanoate)s (PHAs) is an important strategy to tailor their properties for specific applications, but both scopes of functional groups and the methods of transforming them into tailored PHA materials are currently limited and merit further exploration. Here, we report a catalyst-controlled stereoselective ring-opening polymerization of functionalized propiolactones for the synthesis of vinyl-, allyl-, and propargyl-functionalized PHAs with high syndiotacticity (Pr up to 0.95) and a broad glass and melting transition window (Tg down to -31°C, Tm up to 126°C). Copolymerization of such lactones with β-butyrolactone further enhances PHA's thermal robustness and mechanical toughness. Three different methods have been developed to further transform the functionalized PHAs into creep- and solvent-resistant crosslinked PHA thermosets, dynamic-supramolecular elastomeric PHA networks, and grafted PHAs with hydrophilic and bioactive molecules. PHA functionalization, also uncovers a rare example of PHA supramolecular stereocomplexes via blending an enantiomeric, vinyl-functionalized PHA pair.

Mechanically interlocked polymers (MIPs) offer unconventional architectures that expand the design space of polymer chemistry, making them an emerging focus of polymer and supramolecular science. Yet their synthesis still lacks the precision and control established in conventional polymer chemistry. We report a living ring-opening polymerization that enables controlled construction of topologically diverse polyrotaxanes from two monomers─[2]catenanes and c[1]daisy chains. The method delivers main-chain and daisy-chain architectures with predictable molecular weights, narrow dispersities (Đ ≤ 1.19), and block copolymer access. Comparative studies reveal topology-dependent reactivity, underscoring the role of conformational constraints in polymerization kinetics. This unified route establishes a versatile platform for programmable MIP synthesis, bridging molecular topology with materials design and paving the way for next-generation mechanically bonded polymers.

This is the first theoretical investigation that systematically analyzes the interactions between the hexachlorophosphazene, [PCl2N]3, and small molecule impurities H2O and HCl in a 1 : 1 stoichiometric ratio. Utilizing both ab initio methods and seven DFT functionals in conjunction with the triple-ζ basis set, the pivotal structures in proposed reaction mechanisms are fully characterized and the energy change for each step was determined at the CCSD(T)/aTZ‖MP2/aTZ level of theory. Our QM calculations show that [PCl2N]3 can be hydrolyzed via a single-step mechanism with an activation energy of ca. 180 kJ mol−1, or be ring-opened by HCl through a two-step mechanism, in which the rate-determining step has an activation energy of ca. 120 kJ mol−1. Because the activation energy of these two reactions is notably lower than that of the ring-opening polymerization and the ring–ring expansion equilibrium (which requires ca. 240 kJ mol−1 of energy determined at a comparable DFT level of theory), our study indicates that even trace amount of H2O and HCl can significantly interfere with the polymerization process. Beyond revealing new mechanistic details, our calculations also indicate that all selected functionals can provide reasonable electronic structures to describe the reaction progress. On the other hand, while each of the functionals investigated here excels in closely matching the CCSD(T)/aTZ‖MP2/aTZ energy barriers for certain steps in the reaction, the B3LYP functional is capable of providing the most consistent results. This establishes that the B3LYP functional can be suitable for investigating phosphazene reactions as a computationally efficient and robust quantum mechanical approach while maintaining near–ab initio accuracy.

Novel ion-paired alkali metal complexes Na1-Na4 and K1, supported by hexadentate amino-bisphenolate ligands incorporating two pendant heterocyclic rings, were synthesized. In the solid state, the multidentate ligand in Na1 and Na4 coordinates to the metal center in a pentadentate fashion, leaving one heterocyclic ring uncoordinated; in solution, however, these complexes adopt symmetric and fluxional structures. Using benzyl alcohol (BnOH) as an initiator, all complexes efficiently catalyzed the ring-opening polymerization (ROP) of rac-LA at room temperature, delivering isotactically biased PLAs with high activities (TOF up to 37917h-1). At 223 K, the sodium complexes Na1-Na4 exhibited significantly enhanced isoselectivities (Pm = 0.78-0.89), while the potassium complex K1 remained less stereoselective (Pm = 0.64). Among them, Na1 displayed the highest activity and isoselectivity (TOF up to 2407 h-1; Pm = 0.87-0.89). Under optimized conditions ([rac-LA]0/[Na1]0/[BnOH]0 = 2500/1/2), Na1 afforded high-molecular-weight isotactic PLA (Mn = 134 kg/mol, Pm = 0.89). Further decreasing the temperature to 203 K improved the isoselectivity of Na1 to Pm = 0.92 with sufficient activity still retained (TOF = 245 h-1). Based on the ROP studies of L-LA, NMR-scale reactions, and MALDI-TOF mass spectrometric analysis of typical oligomers, it is proposed that at low temperature the ROP of rac-lactide is initiated via a ligand-assisted activated-monomer mechanism in the presence of BnOH.

In search of an alternative to the dominant industrial processes, facilitated mostly by transition-metal catalytic systems, current economic and environmental aspects are leading to a growing interest in the chemistry and application of main group element-based catalysts and materials. Mono- and dinuclear boron and aluminum complexes bearing a biguanide ligand (substituted 4,6-dimethoxypyrimidin-2-yl-guanidinate; L) were prepared by deprotonation of LH2 with BH3·Me2S, BF3·Et2O, Me3Al, or Me2AlCl or, in some cases, by transmetallation reactions of the lithium complex. Complexes were characterized by multinuclear NMR and sc-XRD analyses. Two coordination isomers, where the central atoms can occur both in the four- and six-membered N,N'-chelate ring, were found for homobimetallic aluminum and boron biguanide complexes. A thorough study was performed to understand the formation and isomerization process, where thermally and kinetically conducted isomerization was explored. The relative Gibbs free energies of optimized structures and hypothetical arrangements were calculated and compared in order to support the described isomerization. The activity of selected complexes was tested in the ring-opening polymerization (ROP) of rac-lactide. While the boron complexes are inactive, dimethylaluminum species show moderate activity and good control over the polymer mass and dispersity after iPrOH co-initiation. Furthermore, the species effectively promote hydroboration of unsaturated C-C bonds.

Precise control over microstructure in the ring-opening copolymerization of ε-caprolactone (CL) and lactide (LA) remains challenging because of intrinsic monomer reactivity differences and concomitant transesterification, which often obscure the origin of the final sequence distribution. Here we show that a single tetrameric multinuclear aluminum catalyst provides programmable access to block, near-statistical, and gradient CL/LA copolymers within one catalytic platform. The complex mediates well-controlled ring-opening polymerization of both monomers, enabling the synthesis of diblock, triblock, and multiblock architectures by sequential monomer addition under insertion-dominated conditions. Under simultaneous copolymerization conditions, variation of the reaction temperature modulates the balance between propagation and exchange processes and thereby governs the copolymer microstructure. At lower temperature, the copolymers display reactivity ratios close to unity, average sequence lengths near two, and thermal behavior consistent with near-statistical incorporation. At elevated temperature, enhanced transesterification leads to pronounced growth of homologous sequences and compositional drift along the chains, characteristic of gradient architectures. Taken together, these findings establish a unified kinetic-thermodynamic framework for sequence control in CL/LA copolymerization and reveal multinuclear aluminum catalysis as an effective strategy to traverse distinct copolymer microstructures using an earth-abundant metal system.

Biofouling poses major challenges in marine and biomedical sectors. To overcome the substrate-specific limitations of conventional poly(ethylene glycol) (PEG) coatings, we report herein a versatile, mussel-inspired anchoring strategy. Using catechol-amine functionalized copolyethers, we created substrate-independent antifouling PEG brushes. To elucidate the synergistic role of catechol and amine groups, three control copolymers (catechol-only, phenol-amine, and phenyl-amine) were synthesized via anionic ring-opening polymerization using a PEG macroinitiator. Comprehensive characterization revealed that catechol-amine synergy achieved the highest grafting density (0.82 chains/nm2) and superior antifouling efficacy. Notably, the phenol-amine variant showed higher grafting density than the phenyl-amine control but significantly worse antifouling performance. Suboptimal anchoring leaves exposed chemical motifs that inadvertently promote biofouling. This demonstrates that high grafting density alone cannot guarantee fouling resistance; the chemical integrity of the anchoring moiety is decisive. These findings underscore the catechol-amine platform as a critical requirement for high-performance, robust antifouling interfaces.

The ring-opening polymerization (ROP) of δ-lactones derived from the telomerization of CO2 and butadiene offers a platform to valorize cheap and abundant waste products into commercially competitive products. However, the ROP of multisubstituted δ-lactones is often limited by a lack of exergonicity. Here, our team reports the photochemical activation of 3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one (EVP) through base-catalyzed α,β- to β,γ-photodeconjugation, affording 3,6-divinyltetrahydro-2H-pyran-2-one (DVP) with yields up to 97%, where yields are dependent on the pKa of the catalyst's conjugate acid. Ti(OiPr)4-catalyzed selective ring-opening polymerization results in well-controlled polymerizations with polymer molar masses up to 5 kDa. Thermodynamic analysis of DVP polymerization reveals a ceiling temperature (Tc) of 58 °C, ∼200 °C higher than for EVP, demonstrating how photodeconjugation can be used as a simple tool to improve the polymerization thermodynamics of β-substituted-α,β-conjugated lactones.

The state-of-art commercial polymeric adhesives are mainly petroleum-based, non-biodegradable and not tolerant of low temperature, severely limiting their applications in extremely cold regions. Current research efforts focus on development of sustainable and biodegradable polyester-based adhesives. However, nearly all the reported polyester-based adhesives were used at room temperature, and the innovative functional polyester-based adhesives with low-temperature-resistance are very rare. Herein, we rationally designed and synthesized triblock thermoplastic polyester elastomers, poly(1,4-dioxan-2-one)-b-poly(γ-methyl-ε-caprolactone)-b-poly(1,4-dioxan-2-one) (PPDO-b-PMCL-b-PPDO), serving as high-performance biodegradable hot-melt adhesive with excellent low-temperature-resistance. The mechanical and viscoelastic properties of polyester-based adhesives could be readily modulated by varying molecular weight and fraction of hard/soft blocks via controlled ring-opening polymerization. PPDO-b-PMCL-b-PPDO with appropriate volume fraction of hard blocks exhibited strong adhesion to a range of substrates (with a bonding strength high up to 5.0MPa) both at room temperature and even at cryogenic temperature (-196°C). The polyester elastomer-based adhesives outperformed some common commercial petroleum-based hot-melt adhesives, showing their great potential in the specific scenarios like polar-region exploration.

Synchronous polymerization that combines mechanistically orthogonal pathways within a single catalytic system offers an attractive route to well-defined block copolymers, yet remains challenging because it requires balancing electronically opposing reactions. Here, we systematically investigate how p-block metal chlorides regulate cationic-anionic synchronous ring-opening polymerization (CAP) of 2-oxazolines and cyclic esters. By comparing GaCl3, InCl3, SnCl4, SbCl3, and BiCl3, we found that synchronous copolymerization is broadly accessible across this series, demonstrating the generality and robustness of the CAP framework. In contrast to the overall feasibility of copolymer formation, the rate of oxazoline polymerization is highly sensitive to the identity of the metal center, leading to pronounced differences in propagation kinetics. Kinetic analyses, Lewis acidity measurements, and density functional theory calculations collectively indicate that metal-dependent electronic interactions at the propagating chain end modulate oxazoline activation, whereas cyclic ester polymerization is comparatively less affected. These findings reveal that p-block metal chlorides primarily act as kinetic regulators in synchronous CAP systems. By decoupling polymerization feasibility from rate control, this work clarifies the role of metal identity in multi-mechanistic polymerizations and provides a general strategy for tuning polymer growth without compromising architectural precision.

Ion-conducting polymer chemistry and microstructure profoundly impact membrane water uptake and ionic conductivity. Water uptake strongly impacts ionic conductivity; yet excess water uptake compromises ion-exchange membrane mechanical properties. Although nanophase separation has been proposed to overcome this trade-off, it is unclear how polymer backbone architecture governs ionic nanostructure and its subsequent impact on water uptake and conductivity. Here, we integrate experiments and molecular dynamics simulations to elucidate the role of backbone chemistry in governing ionic nanostructure, hydration behavior, and ion transport in anion-conducting polyelectrolytes (ACPs). We systematically investigate hydrocarbon polynorbornene (PNB)-based ACPs with three distinct backbone architectures: vinyl-addition polymerization (VAP), ring-opening metathesis polymerization (ROMP), and hydrogenated ROMP. While maintaining comparable ion exchange capacities (IECs) and identical side-chain chemistry, we isolate the effects of backbone structure. We show that nanophase-separated ionic nanostructures originate in the dry state and evolve upon hydration through heterogeneous water uptake, with water preferentially partitioning into ion-rich domains. This nanophase separation arises from a delicate interplay between ionic segregation propensity and the entropic barrier imposed by backbone stiffness. Specifically, flexible backbones intensify attractive ion-ion interactions by reducing the entropic penalty for backbone deformation, promoting nanophase separation, while rigid backbones suppress ionic nanostructure formation. Nanophase-separated ion domains locally concentrate water upon hydration, which in turn enables the connectivity required for fast transport at lower water concentration values. These findings demonstrate that backbone chemistry can be tuned as a design lever to promote nanophase separation and enhance ion transport without excessive water uptake.

The recycling of low-density polyethylene (LDPE) is challenging due to difficulties with sorting and contamination, leading to environmental harm. Polyhydroxyalkanoates (PHAs) are at the forefront of high-performance biodegradable alternatives to olefinic plastics, but few offer LDPE-like properties such as low strength and crystallinity while maintaining high ductility and thermal stability. Herein, we report a series of isoenriched trans-poly(3-hydroxy-2-methylbutyrates) (trans-PHMBs) with tunable mechanical and thermal properties. These polymers were synthesized through ring-opening polymerization of racemic trans-3,4-dimethylpropiolactone (rac-trans-DMPL), sourced from C1 and C4 feedstocks, using a new class of "sandwich" C2 symmetric rac-(ArBDI*)ZnOiPr catalysts (where BDI = β-diketiminate). Variation of aromatic groups (Ar) and polymerization temperature yielded mm%s between 45-79% and melting temperatures (Tm) between 141-174 °C. trans-PHMB with intermediate isotacticities of 73 and 75 mm% exhibit similar stress-strain profiles to LDPE, indicating that these polymers have the potential to serve as higher melting, degradable substitutes for LDPE.

The ability of block copolymers (BCPs) to self-assemble into microphases allows the creation of unique materials with enhanced tailored properties. In this study, we combined organocatalyzed polycondensation and ring-opening polymerization (ROP) to create fully biobased ABA triblock copolymers consisting of poly(1,6-hexanediol) (PHDO) and poly(l-lactide) (PLLA). Increasing the segregation strength (χN) from 4 to 11 causes the triblocks to shift from weak to intermediate segregation, with PHDO microphases dispersed within a PLLA-rich matrix. Long-range order appears when χN ≥ 6, resulting in a body-centered cubic (BCC) spherical morphology. Depending on thermal history, distinct hierarchical structures, including BCC spherical morphologies, BCC plus lamellar arrangements, and interdigitated double-lamellar structures, were obtained. Increasing the molar mass of the PLLA terminal blocks (MnPLLA = 18.5 kDa) enabled the formation of self-supporting films, for which preliminary mechanical and gas permeation properties were evaluated. Overall, this work establishes structure-morphology relationships of fully biobased double-crystalline triblock copolymers.

Inside membranes: unveiling chain conformation in poly(butylene oxide)-block-polyglycidol polymersomes.