Polymer Chemistry最新文献

Tailoring the properties of functional polymers through simple structural modifications is a fascinating molecular design strategy. In this work, cyano functionalization of the polymer backbone improved the electrochromic properties of the conjugated porous polymer (CPP) composed of N,N,N′,N′-tetraphenyl-1,4-phenylenediamine (TPPA) and thienylene-vinylene-thienylene (TVT) units. The non-cyanated polymer P(TPPA-TVT) shows multicolor behavior, reversibly switching among orange-yellow, gray-green, and gray. The cyanated polymer P(TPPA-TVTCN) not only exhibits a different neutral-state color but also presents more diverse electrochromic color changes, including brick red, reddish brown, brown, green, and gray-cyan. In addition, the modification of the cyano group improves the cycling stability of the polymer. P(TPPA-TVTCN) retains over 96% of its initial optical contrast after 2000 seconds of repeated redox switching, with a performance significantly superior to that of P(TPPA-TVT). Moreover, P(TPPA-TVTCN) shows better kinetic properties than P(TPPA-TVT) in the near-infrared (NIR) region. At 1380 nm, P(TPPA-TVTCN) displays an optical contrast of 52.6%, response times of 0.76 s and 2.05 s, as well as a coloration efficiency of 231.52 cm² C⁻¹. The incorporation of the cyano group promotes the formation of a D–A configuration and hence optimizes the optoelectronic properties of the polymer. Besides, the porous structures and extended π-conjugated backbones of the two CPPs help reduce the response time and enhance the cycling stability. Rational polymer design and facile structural adjustment provide an effective way for developing new electrochromic materials.

The potential of diazoacetamides as a class of monomers for Pd-initiated C1 polymerization was investigated. Copolymerization of a series of diazoacetamides with ethyl diazoacetate (EDA) proceeded to afford relatively high M_n copolymers with a diazoacetamide composition of ca. 10 mol% (e.g., M_n = 9800; diazoacetamide composition = 11 mol%), indicating that the presence of certain diazoacetamides did not prevent the progress of the C1 polymerization. Hetero-bis(diazocarbonyl) compounds with diazoacetate and diazoacetamide groups incorporated in one molecule were designed and prepared for cyclocopolymerization for the first time. The Pd-initiated cyclocopolymerization of the monomers proceeded to yield cyclopolymers with ester and amide linkages in a repeating cyclic framework and M_n values of a few thousand, demonstrating that 1 : 1 alternating copolymerization of diazoacetate and diazoacetamide is indeed possible with a suitable design of the monomer structure and an appropriate choice of the Pd-based initiating system. The chain end analysis of the cyclopolymer using MALDI-TOF-MS measurements suggested that chain transfer through β-H elimination of the acetamide propagating species prevented the formation of high M_n polymers.

We report a solvent-free melt polycondensation strategy for synthesizing a partially biodegradable isosorbide-based polycarbonate (ISB-based PC) incorporating ethylene oxide (EO)-functionalized comonomers. The incorporation of a minor fraction of EO-modified bisphenol A (5 mol%) significantly enhanced polymerizability, yielding PC with enhanced molecular weight (M_w up to 64 360; dispersity (Đ) ≈ 1.80), improved tensile strength (up to 71.7 MPa, surpassing conventional non-degradable biomass-based PCs at ∼60 MPa), and excellent optical transparency (90.3–93.0%). The polymer exhibited a high glass transition temperature (T_g = 135.7 °C) and enhanced mechanical flexibility due to EO-containing segments. ISO 14855-1-based biodegradation tests revealed 16.7% mineralization over 70 days, significantly exceeding the rates of both petroleum-derived and biomass-based non-degradable polycarbonates. MTT assays confirmed negligible cytotoxicity toward HaCaT keratinocytes, affirming the material's biocompatibility. Green chemistry metrics (E-factor = 0.98, PMI = 1.98, atom economy = 50.5%) demonstrate the environmental efficiency of the process, outperforming conventional phosgene-based approaches. This study presents a scalable and sustainable approach for designing bio-based polycarbonates combining partial biodegradability, cytocompatibility, and desirable material properties. Strategic inclusion of a minimal amount of BPA-EO facilitates bridging high performance with green design, laying a foundation for future development toward fully bio-based systems. The results align with green chemistry principles, highlighting ISB-based PC as a promising candidate for applications in packaging, coatings, and medical devices.

Poly(methyl methacrylate) (PMMA) is widely studied for its attractive properties, including good processability, excellent optical characteristics and low cost. Nevertheless, a persistent challenge for PMMA-based materials is their limited thermal stability. Herein, a series of PMMA copolymers containing perfluorocyclobutyl (PFCB) aryl ether groups were prepared to enhance the heat resistance of PMMA-based materials via the introduction of rigid PFCB aryl ether moieties and the formation of a cross-linked network. PFCBMA, a methacrylamide monomer containing a PFCB aryl ether moiety, was first synthesized and copolymerized with MMA to afford PFCB-containing PMMA copolymers (PPFCBMA-co-PMMA), which exhibit higher glass transition (T_g) and thermal decomposition (T_d) temperatures than PMMA. Subsequently, a dimethacrylamide monomer bearing a PFCB aryl ether moiety (MAPFCBMA) was synthesized and copolymerized with MMA to afford crosslinked PMMA copolymers (cross-PFCB-PMMA) with PFCB units serving as crosslinking points. These cross-PFCB-PMMA polymers show much higher thermal decomposition temperatures than pure PMMA and PPFCBMA-co-PMMA. Furthermore, no glass transition was observed below 250 °C in DSC analysis of cross-PFCB-PMMA polymers. This work demonstrates that incorporating PFCB aryl ether moieties, introducing amide bonds and constructing a crosslinked network are effective strategies for improving the thermal stability of PMMA-based polymers.

Ionic liquid crystals have various potential applications enabling selective and effective transportation. Herein, we report the development of separation membranes prepared by fixing liquid-crystalline (LC) columnar (Col) nanostructures through the in situ polymerization of the film states formed by imidazolium-sulfobetaine ionic liquid crystals. We compared the properties of the nanostructured betaine liquid crystals with those of analogous Col structures containing mono-ionic groups such as imidazolium and trialkyl ammonium moieties. The betaine LC compounds formed more thermally stable LC phases than the mono-ionic LC compounds having analogous structures. For salt permeation in water treatment, the betaine LC membrane exhibited ion selectivity, which was different from those of the mono-ionic LC membranes. During virus filtration, the water flux of the betaine membrane was the highest among other analogous nanostructured Col membranes. For gas separation, these Col LC membranes showed selective CO₂ permeation properties and exhibited an αCO₂/N₂ selectivity of about 30 under highly humidified conditions.

Dibenzobarrelene-based N-heterocyclic carbenes (NHCs) offer tunable steric and electronic properties, making them attractive ligands for Pd catalysis. Herein, we report a family of “large-but-flexible” Pd-NHC precatalysts that enable room-temperature Suzuki–Miyaura polycondensations (SMPs) of sterically hindered and electronically challenging aryl dichlorides. Key features include 2,6-diethylphenyl-substituted NHCs and 3-chloropyridine, which cooperatively promote C–Cl activation. Structural and variable-temperature-NMR analyses reveal suppressed C_Ar–N bond rotation and a conformationally adaptive ligand environment. The system affords high-molecular-weight π-conjugated polymers with broad monomer scope and good solubility. Significantly, it achieves electrophile-selective coupling of aryl chlorides to construct sequence-defined polymers, offering a more practical alternative to traditional nucleophile-based strategies. Mechanistic studies suggest a dynamic ligand exchange equilibrium that stabilizes the active Pd(0) species. These findings establish a robust and versatile platform for low-temperature polycondensation of aryl dichlorides.

Photoresponsive gels exhibit various applications because they can change their structures and properties under the stimulation of light. However, the use of photoresponsive gels is limited by solvent evaporation, which compromises their longevity and functionality. Herein, we design a metallopolymer organogel to overcome this challenge. The organogel incorporates metal–ligand coordination bonds as reversible, photoswitchable crosslinks within a polyacrylamide network, using high-boiling-point 1,2-propanediol as the solvent. This system exhibits excellent stability against solvent loss and displays fully reversible and photoresponsive behaviors, including gel-to-sol transitions, color change and volumetric expansion/contraction. We use these properties to demonstrate rewritable photopatterning and shape reconfiguration. We also demonstrate that the organogel maintains low solvent evaporation and stable performance even under high-temperature conditions. The metallopolymer organogel design opens avenues for the development of long-lasting, intelligent soft matter for use in demanding applications.