ACS polymers Au最新文献

This study presents the synthesis of a covalent organic framework (TPBT-COF) via the Schiff-base reaction and its integration with carbon nanotubes (CNTs) and reduced graphene oxide (rGO) through in situ polymerization, yielding TPBT@CNT and TPBT@rGO composites. To develop environmentally friendly electrode materials, the TPBT@CNT and TPBT@rGO composites were blended with regenerated cellulose (RC), forming TPBT@CNT/CNT/RC and TPBT@rGO/rGO/RC films. The TPBT@CNT/CNT/RC film-based electrode exhibited superior capacitive performance due to its uniform composition, achieving a specific capacitance of 1288.26 F/g at 0.5 A/g. In contrast, the TPBT@rGO/rGO/RC film-based electrode showed a lower capacitance of 398.75 F/g at 0.5 A/g, attributed to the uneven material distribution. Both composite film-based electrodes demonstrated excellent cycling stability, retaining 85.87 and 81.82% of their initial capacitance after 10,000 cycles, respectively. In a symmetric device configuration, the TPBT@CNT-50/CNT/RC (35/35/30, w/w) electrode achieved a specific capacitance of 84.32 F/g at 1 A/g, with a maximum energy density of 11.71 Wh/kg and a power density of 312.5 W/kg, while maintaining 77% of its initial capacitance after 10,000 cycles. These findings underscore the potential of TPBT-COF-based composites as sustainable, high-performance electrode materials for energy storage applications.

Motivated by growing concerns over the impact of conventional organic solvents on humans and their environmental safety, this review highlights recent advancements in the application of renewable resource-derived solvents in reversible deactivation radical polymerization (RDRP) techniques, with a focus on their effectiveness and potential benefits. The review begins with a concise overview of the importance of environmentally friendly solvents, outlining the specific requirements associated with their use. It then details the key parameters used to classify and evaluate solvents. Subsequently, the review examines the role and influence of solvents in various RDRP techniques, with particular attention to green solvents, especially those derived from biomass, that are gaining increasing attention in polymer synthesis. Three major classes of biomass-derived solvents are discussed: (1) lignocellulosic biomass, (2) essential oils, and (3) vegetable oils. These sustainable alternatives address both the depletion of fossil resources and environmental concerns associated with traditional solvents. The review highlights the promising outcomes achieved using these biobased solvents, demonstrating their potential to enhance the sustainability and environmental compatibility of controlled polymer synthesis.

We report the combined experimental and theoretical study of the bulk self-assembly behavior of polystyrene-block-poly-(2,3,4,5,6-pentafluorostyrene) diblock copolymers. These block copolymers were designed to create highly antagonistic blocks (with a high Flory-Huggins interaction parameter, χ) with minimum disruption to the molecular construct (i.e., only replacing five hydrogen atoms with five fluorine atoms). A large library of diblock copolymers (41 samples) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization to map out a major portion of the phase space. All block copolymers exhibited narrow molecular weight distributions with dispersity (D) values between 1.07 and 1.32, and subsequent thermal annealing revealed phase separation into well-defined nanoscale morphologies depending on their molecular composition, as determined from small-angle X-ray scattering and transmission electron microscopy analyses, with an experimental phase diagram being constructed. The χ value at 25 °C for this block copolymer was estimated to be 0.2 using strong segregation theory, based on trends in phase-separated domain spacing and interfacial width. When applying theoretical approaches, the majority of the domain spacing data trends were captured by a coil-coil diblock copolymer model; however, a better fit to the data for samples with shorter fluorinated blocks was obtained with a rod-coil model, indicating that the chains in these fluorinated blocks likely have a higher inherent stiffness and were thus rod-like. This observation demonstrates that, due to the very high value of χ, a transition from coil-coil to rod-coil behavior can be obtained purely by reducing the length of the stiffer of the two blocks and without varying temperature or the chemical composition of the polymers. This work showcases the presence of strong microphase separation within AB diblock copolymers despite the relatively similar chemical composition of the constituent "A" and "B" units, with a clear transition from rod-coil to coil-coil segregation behavior.

The properties of polymers depend on the structure of the backbone and the types of side groups linked to the backbone. Most well-known synthetic polymers have both the skeleton and the side groups derived from organic precursors and ultimately from petroleum. These have proved to be transformative in many areas of materials science and in other fields that were hitherto dominated by biological polymers, metals, or ceramics. However, many classical organic polymers have serious deficiencies such as flammability, biomedical incompatibility, sensitivity to high energy radiation, or unwanted persistence in the environment. This is partly a consequence of limits to the types of side groups that will survive or permit a normal polymerization process. Moreover, side groups introduced by classical polymer synthesis techniques generally cannot be exchanged for other groups after the polymer has been assembled. By contrast, one of the main access routes to poly-(organophosphazenes) uses organic or inorganic nucleophiles to replace the chlorine atoms in poly-(dichlorophosphazene), (NPCl₂) _n, in a process of macromolecular substitution. The resultant polymers have unique characteristics derived from both the inorganic skeleton and a wide range of different side groups. This provides hitherto inaccessible property combinations that are appropriate for medical devices, aerospace materials, fire-resistant textiles, batteries, and semiconductor components, many of which cannot be achieved through classical polymer science.

Graft polymers with degradable backbones and precisely tunable side chains are highly desirable for advanced functional materials, particularly in biomedical and stimuli-responsive systems. Herein, we report a versatile strategy to synthesize degradable graft polymers via a reversible addition-fragmentation chain transfer (RAFT) step-growth polymerization approach using bifunctional poly-(methyl acrylate) (PMA) macromonomers and a bifunctional vinyl monomer. The polymerization proceeds through an A₂ + B₂-type polymerization mechanism, wherein the steric hindrance from macromonomers is effectively alleviated by incorporating a small-molecule RAFT agent as a comonomer. The resulting graft copolymers exhibit tailorable side-chain lengths and tunable rheological properties. Notably, the polymer backbones feature dual stimuli-responsive degradability enabled by xanthate and ester linkages, allowing stepwise degradation via aminolysis and hydrolysis. Furthermore, RAFT functionalities embedded in the backbone allow postpolymerization chain expansion, offering control over both the backbone architecture and graft density. This work provides a modular and robust platform for engineering degradable graft polymers with programmable architectures and multifunctionality suitable for applications in drug delivery and smart materials.

Bacterial nanocellulose (BNC), a renewable biopolymer biosynthesized by specific bacterial strains, exhibits exceptional mechanical strength, water retention, and biocompatibility due to its nanofibrillar 3D architecture and high purity. Functionalizing BNC with conductive polymers, metal nanoparticles, enzymes, and peptides unlocks its potential for diverse applications in smart bioelectronics, including biosensors, neural interfaces, and tissue engineering. This review presents a comprehensive analysis of recent strategies for tuning BNC's electrical, optical, biological, and mechanical properties to meet the evolving demands of next-generation biomedical and wearable devices. We discuss a broad range of functionalization methodsfrom in situ nanoparticle synthesis and electrostatic assembly to cross-linking and doping with ionic liquidsand explore their role in enhancing conductivity, stimuli-responsiveness, and cellular interactions. Furthermore, we examine BNC-based nanocomposites designed for biosensing, wound healing, optoelectronic sensing, and flexible implantable systems. The review concludes by outlining current key hurdles including scalability, device integration, long-term stability, and stringent regulatory requirements for safe production, use, and clinical translation, while uniquely positioning BNC through a cross-domain comparison of biomedical and electronic applications, complemented by techno-economic insights into scale-up, cost, and regulatory challenges.

Real-time monitoring of particle size distribution (PSD) during emulsion polymerization is vital for understanding reaction mechanisms and improving process control. Conventional offline methods such as Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Capillary Hydrodynamic Fractionation chromatography (CHDF), while accurate, are limited in their ability to capture dynamic changes during the reaction. OptoFluidic Force Induction (OF2i) is a novel optical tweezers-based technology that enables online, in situ particle characterization. Although previously applied in pharmaceutical contexts, its utility in polymer reaction monitoring remains untested. This study evaluates the performance of OF2i in stirred-tank reactors during ab initio and semibatch emulsion polymerizations of styrene and acrylic comonomers. OF2i successfully tracked the evolution of particle size and PSD throughout various reaction stages, including primary nucleation in micelle-free systems, particle growth in seeded semibatch setups, and secondary nucleation simulated through sequential seed additions. It delivered accurate PSD measurements for particles larger than ∼180 nm in polystyrene latexes and ∼200 nm in (meth)-acrylated copolymer systems, with a current temporal resolution of 10 min governed by the system's automated dilution interface. PSD results were consistent with those obtained by established offline techniques such as DLS, TEM, and CHDF. The system's ability to operate without composition-specific calibration and to provide continuous, high-resolution data makes it uniquely suited for monitoring transient dynamics and population shifts in real timecapabilities not achievable with conventional methods.

Dynamic covalent bonds provide a powerful tool to design recyclable rubber-based materials. Among possible strategies, imine chemistry offers a valuable approach for achieving an adaptive network. In this work, for the first time, the use of biobased ketones and amines as cross-linkers in a rubber network is used. Specifically, epoxidized natural rubber (ENR) was cross-linked with glycerol trilevulinate (GT) and hexamethylene diamine (HMDA) to produce a fully biobased and recyclable hybrid network based on imine and hydrogen bonds. Comprehensive characterization confirmed the formation of a hybrid adaptive network, while mechanical tests demonstrated that the optimal formulation (5 phr GT and 5 phr HMDA) achieved the best performance after recycling, showing a significant increase in tensile strength while maintaining stable strain at break. The material's ability to reconstruct its network upon reprocessing was supported by cross-link density measurements via swelling and mechanical analyses, while dielectric investigations further confirmed the presence of dynamic interactions. The observed recyclability was thus attributed to the synergistic effect of covalent and noncovalent bonds, which reorganized effectively to preserve network integrity and mechanical performance. This work demonstrates the potential production of a biobased, recyclable and adaptable rubber network with excellent mechanical properties, highlighting how levulinic acid derivatives represent an optimal system for the development of sustainable rubber materials.

Vat photopolymerization is a widely adopted additive manufacturing technique valued for its high resolution, smooth surface finish, and rapid production speed. Recently, it has gained prominence in the fabrication of polymer nanocomposites, as liquid photopolymer resins allow efficient incorporation and dispersion of nanoparticles. Current research in vat 3D printing of polymer nanocomposites is directed toward creating materials with enhanced functionalities, enabling the development of advanced functional components. Among different nanofillers, semiconducting metal oxide nanoparticles (MOx NPs) such as TiO₂, ZnO, Fe₃O₄, Cu₂O, and ZrO₂ are of particular interest. These NPs act not only as functional additives but also as photocatalysts, directly influencing photopolymerization kinetics, cross-linking density, and final properties. Mechanical performance is enhanced through nanoreinforcement, provided that homogeneous NP dispersion is achieved. This enables lightweight, high-performance parts for aerospace, automotive, and biomedical engineering. MOx NPs also improve thermal stability, supporting applications in electronics, automotive systems, and energy devices. Adjustments in electrical and dielectric properties open further potential in power electronics, high-voltage insulation, and wearable devices. Incorporation of superparamagnetic Fe₃O₄ introduces magnetic functionality, useful for microactuators, sensors, and graded materials. Optical properties can likewise be tailored, with MOx/polymer nanocomposites enabling photodetectors, optoelectronic components, and functional thin films. In the biomedical field, biofunctional performanceranging from antimicrobial activity to tissue compatibilityhas been exploited in dentistry, tissue scaffolds, and micromachines for drug delivery. Despite these advances, challenges such as nanoparticle aggregation, viscosity increase, light scattering, and altered reaction kinetics still limit the achievable filler loadings and overall performance of vat-printed nanocomposites. This review therefore emphasizes both the potential and the limitations of incorporating MOx nanoparticles into vat photopolymerization, outlining the current state of knowledge and key challenges that must be addressed to enable application-oriented functional materials.

High-permittivity polysiloxanes are attractive for applications in dielectric actuators, sensors, energy devices, and electrolytes. A major challenge is the synthesis of polar polysiloxanes with well-defined end groups suitable for controlled cross-linking while minimizing cycle content that can compromise performance. Here, we report the synthesis of polysiloxanes bearing 3-cyanopropyl side groups and aminopropyl or vinyl end groups, with controlled molecular weights and reduced cyclic byproducts. While the reactions in chlorinated solvents predominantly give short chains, the nonchlorinated solvents favor cycle formation. In contrast, hydrolysis-condensation of (3-cyanopropyl)-methyldichlorosilane under solvent-free conditions yields high-molecular-weight polymers (≈14 kg mol^-1) with only 11% cycles, which are readily removed by toluene extraction. Additional polymer growth is achieved via anionic ring-opening polymerization of isolated cycles, yielding polymers up to 25 kg mol^-1. Finally, silanol end groups are quantitatively converted into aminopropyl (100%) or vinyl groups (92%), which are useful for cross-linking the polymers to elastic networks with improved structural control.