RSC Applied Polymers最新文献

Many are pursuing high-performance polymer composites with ultra-high inorganic fillers, focusing on improving inorganic particle dispersion. However, few studies have explored how to address the heterogeneity introduced by inorganic particles after meeting dispersion requirements. This work proposed that resolving the heterogeneity in polymer composites with high inorganic particle content relies on utilizing the movement of polymer chains for self-adaptation. We employed ultra-high-filled tungsten powder (W)/high-density polyethylene (HDPE) composites as the basic model. A vitrimer was introduced to enhance the intensity of mutual diffusion of HDPE chains during static hot pressing. The vitrimer-modified W/HDPE composites (W/HDPE-v) not only ensured the high dispersion of W but also facilitated intense mutual diffusion of the chains through the bond exchange of the vitrimer under thermal action. This process led to the ordered stacking of the C–C main chains and increased the crystallinity of the composites. Through the chains’ mutual diffusion, fluctuations in the modulus of the HDPE matrix were reduced, and the interfacial layer between the HDPE and W underwent continuous dynamic reorganization. This dynamic reorganization achieved heterogeneity reduction. The introduction of the vitrimer also generated regions within the polymer chains that exhibited different steric hindrances, which were significantly influenced by factors such as the crosslinking agent content and external forces. This resulted in a directional bond exchange of the vitrimer and traction on the polymer chains, promoting the self-aggregation of polymer chains and the rejection of inorganic particles. The final composites exhibited good mechanical properties and gamma-ray shielding effects.

Ion conduction at high temperatures is critical for the improvement of working efficiency and stability of energy-conversion and -storage devices. Ceramics and highly rigid polymers are generally applied for achieving this; however, their poor processability and mechanical properties hinder their extensive applications. Herein, a sub-nanometer anionic metal oxide cluster ({V₆O₁₃[(OCH₂)₃CR]₂}²⁻) was covalently integrated into polymer networks for high-temperature solid-state conduction of H⁺ and Li⁺ single-ion electrolytes. The hexavanadate cluster was functionalized with acrylate groups, and it served as a nanoscale bifunctional crosslinker to copolymerize with poly(ethylene glycol) methacrylate for the fabrication of polymer networks. The associated counter-cations of the immobilized hexavanadate could be fully solvated in the melts of poly(ethylene glycol) for realizing high mobilities, contributing to promising single-ion conductivities and achieving an Li⁺ transference number of 0.84. According to dielectric spectroscopy studies, the transport of Li⁺ ions was directly mediated by side chain dynamics. The counter-cations could be feasibly switched for the conduction of various cations, such as H⁺ and Li⁺. Meanwhile, the covalent and supramolecular interactions between the polymer and inorganic hexavanadate afforded enhanced stability and robust ionic conduction at temperatures as high as 200 °C. Thus, this work provides versatile platform chemical systems for robust solid-state single-ion conduction at high temperatures.

Biopolymers such as gelatin, hyaluronic acid, and chitin are used in the form of hydrogels as scaffolds for tissue engineering and as bioinks for bioprinting. The biopolymers themselves tend to be weak and hence are usually chemically functionalized to improve their stability and tenacity. The chemical functionalization is currently conducted using batch methods, which are time-consuming, difficult to scale up, and have batch-to-batch variation. Flow chemistry, on the other hand, is more efficient, safer, reproducible, easy to scale up, and can give much higher space–time yields compared to batch reactions. In this study, a flow chemistry protocol was developed for the synthesis of the commonly used biomaterial gelatin methacrylate (GelMA), and the resulting GelMA was used in bioprinting and as a hydrogel in cell culture studies to investigate its ability to support cell attachment and expansion. It was found that conversion of gelatin into GelMA proceeded rapidly and optimally at 60 °C, giving reproducible and high degrees of substitution (65–85%) and high yields in up to 20 minutes of reaction. Scale-up of the reaction was also demonstrated. The resulting GelMA was characterized by oscillatory shear rheometry and was found to be capable of extrusion bioprinting, yielding self-supporting and defect-free hydrogel patterns. The GelMA hydrogels were also found to be able to support the proliferation of primary endometrial cells over 6 days of culture. The GelMA produced by flow chemistry, therefore, was shown to be suitable for use as a bioink and as a hydrogel substrate for cell culture, demonstrating the potential of flow chemistry as an efficient method to produce biomaterials for bioprinting and tissue engineering applications.

THP-1 is a monocytic cell line which can differentiate into macrophage and dendritic cells, widely used in immunology. Immune cells are particularly sensitive to cryopreservation, leading to low recovery and/or reduced differentiation capacity compared to non-frozen cells. Current cryopreservation protocols are unsuitable to cryopreserve THP-1 cells in ‘assay-ready’ format, due to the time and resource intensive culturing steps required post-thaw to recover functional cells. We report the cryopreservation of THP-1 cells in vial and multi-well plate format, with significantly enhanced recovery compared to commercial cryoprotectants. This was achieved using macromolecular cryoprotectants (polyampholytes and ice nucleators) which doubled post-thaw recovery relative to DMSO-alone and improved macrophage phenotype post-differentiation comparable to non-frozen controls. Cryo-Raman microscopy demonstrated that the polyampholytes reduced intracellular ice formation compared to DMSO-alone. These results will enable routine banking and ‘assay-ready’ THP-1 cells direct from the freezer, accelerating immunological research.

Bio-based packaging films with good barrier properties to preserve quality, ensure safety, and extend the shelf-life of food products are in great demand as our society becomes more environmentally conscious. Herein, entirely bio-based nanocomposite films of the ethylcellulose (EC) matrix, reinforced with modified nanofibrillated cellulose (mNFC), have been studied. The NFC modification consisted in a microwave-assisted esterification reaction with three different acids – lactic acid (LA), lauric acid (LU), and stearic acid (SA) – of varying carbon chain lengths, in three solvents (water, ethanol, and ethyl acetate). The highest degree of substitution (DS) for mNFC-LA was achieved in ethanol, while mNFC-LU and mNFC-SA showed the maximum DS (up to 1.22) in ethyl acetate. The success of NFC surface modification was confirmed by titration, FTIR, XRD, SEM, and nanocellulose dispersion behavior. The films of EC-based nanocomposites were prepared by solvent casting and then examined for surface morphology, microstructures, mechanical properties, surface properties and barrier properties against water vapor and oxygen transmission. The findings revealed that integrating mNFC into EC can greatly improve the properties of the films due to their good compatibility, good dispersion ability, and strong interface, which is influenced by the substituted side chain on the mNFC surface. For the best side chain length (3 carbon atoms), mNFC-LA increased the tensile strength of the EC film by up to 130% while reducing the oxygen transmission rate (OTR) by 98%, making it a viable and environmentally benign alternative to PET films. This research offers insights into employing various modified nanocellulose to improve biopolymer-based films for high-barrier packaging and coating applications.

Recent studies have shown that introducing vinylene bridges into naphthalenediimide (NDI)-based dual-acceptor copolymers is an effective strategy to improve backbone coplanarity and charge transport properties in organic field-effect transistors (OFETs). However, their potential as multifunctional materials for broader optoelectronic applications remains unexplored. In this study, we designed and synthesized four vinylene-bridged NDI (vNDI)-based conjugated polymers containing benzothiadiazole (S), benzotriazole (N), triazolobenzothiadiazole (NS), and benzobistriazole (NN) as second acceptors. Structural analysis revealed that the backbone conformation and electron-withdrawing ability of the acceptors significantly influence optical and electronic properties. Among them, vNDI-NS exhibited the narrowest optical bandgap (1.05 eV), while vNDI-N displayed the highest ambipolar mobility in OFETs, attributed to enhanced crystallinity and improved π–π stacking. Furthermore, these polymers were applied as photothermal membranes in solar steam generation (SSG) devices. Films based on vNDI-NS and vNDI-NN achieved solar-to-vapor conversion efficiencies of 58.3% and 56.4%, respectively, under 1 sun illumination. This study expands the applications of vNDI-based polymers beyond OFETs, providing a dual-functional platform combining electrical and photothermal performance.

Advancements in all-organic dielectrics are crucial for electrical energy storage devices and flexible electronics due to their low cost and easier processability compared to inorganic materials for similar applications. In the present work, epoxy-based all-organic nanodielectric materials were developed for capacitive energy storage applications. To be employed as fillers, nanofibres were developed by means of electrospinning, utilizing two polymers, polyvinyl alcohol (PVA) and chitosan (CS). Three cases were examined with nanofibers consisting of pure PVA (5% w/w in epoxy) and PVA : CS in weight ratios of 5 : 1 and 5 : 2 (both 4% w/w in epoxy). The morphological, structural, thermal and dielectric properties of the developed polymer nanodielectric materials were extensively investigated, with a clear focus on their ability to store and recover energy in a capacitor configuration. The presence of CS appeared to significantly increase the dielectric permittivity and restrict charge transport, which is beneficial for energy recovery efficiency, attributed to its strongly insulating nature.

The transfer of bacteria between dry, high-touch surfaces in healthcare settings is a key contributor to hospital-acquired infections (HAIs). In this study, we systematically investigated the relationship between the chemistry of polymer surfaces and the corresponding touch-transfer of microorganisms. The polymers investigated included polymer zwitterions, PEGylated polymers, poly(tetrafluoroethylene) (PTFE), and polystyrene (PS). Water contact angle measurements confirmed the breadth of surface energies of these polymers, ranging from <25° (polymer zwitterion) to >100° (PTFE). A touch transfer model was developed to study bacteria transfer by “finger touches” on an agar plate. The amount of Escherichia coli (E. coli) or Staphylococcus aureus (S. aureus) transferred after each touch was quantified via plate counting. For E. coli, the transfer rate was ∼29% on zwitterionic copolymer surfaces, whereas PS exhibited a much higher rate of ∼67%. For S. aureus, the transfer rate was ∼17% for the polymer zwitterion and ∼100% for PS. The low transfer rates from the polymer zwitterion were comparable to those of PTFE (∼19% for E. coli and ∼17% for S. aureus). These findings demonstrate the role of polymer composition and surface chemistry in bacterial transfer and provide insights for designing materials that effectively minimize microbial transmission in healthcare environments.

Additive manufacturing has revolutionized the fabrication of complex 3D materials. Hydrogels are commonly used as “inks” in 3D printing and offer easy mixing and processing of many materials. Here, the synthesis and characterization of a new library of thermoresponsive ABC triblock copolymers based on oligo(ethylene glycol) methyl ether methacrylate (OEGMA, Molar Mass, MM = 300 g mol⁻¹, A block), 2-phenylethyl methacrylate (PhEMA, B block) and di(ethylene glycol) methyl ether methacrylate (DEGMA, C block) is reported. Polymers of different comonomer compositions were fabricated and investigated in terms of their aqueous solution properties and their ability to form thermogels. The most promising polymer was then used to fabricate a graphene-containing ink, and graphene constructs were successfully printed and characterized in terms of the electrical conductivity properties.

Synthetic polymers play an important role in medical devices such as implants, wound dressings and catheters since the first use of polyethylene in bone and cartilage implants in the 1940s. Since then, many more synthetic polymers have been used in medical devices for applications ranging from orthopaedic implants, wound care products, heart valves, and stents to tissue grafts. However, nearly all the polymers used in these devices are bioinert, except for some that are biodegradable such as polyesters. These polymers generally do not confer bioactivity on their own and need additional stimuli such as through modification with biomolecules or blending with bioadditives. We term polymers chemically modified with biomolecules “Biohybrid Polymers” and they represent a new class of biomaterials that are purely synthetic. These biomaterials possess properties required for use in applications such as tissue engineering and medical device fabrication. In this review, we explore the different types of biohybrid polymers that have been reported for use in skin, bone and cartilage tissue engineering with brief descriptions of their chemical synthesis methods. The materials are categorised based on their targeted applications in wound care or orthopaedics to help readers understand what are the potential materials that may be used for each type of tissue being regenerated.