Reactive & Functional Polymers最新文献

Superwetting membranes have good prospective for treatment of oil-containing wastewaters. However, development of highly adhesive superhydrophobic membranes with efficient oil-water separation performance remains a great challenge that needs to be addressed urgently. Herein, highly adhesive membrane surface with hierarchical structure were fabricated by in-situ TEOS hydrolysis and fluorinated modification. The interface bonding force between polyvinylidene fluoride (PVDF) and silica nanoparticles (SiO₂ NPs) was increased through the dopamine self-polymerization and adhesion. The hierarchical structure was obtained by simultaneously adjusting TEOS and ammonia contents. The three-dimensional hierarchical membrane structure which is similar to that of a rose petal was shown by SEM analysis. The obtained membrane showed a water contact angle of 158 ± 2°, while the oil contact angle approaches 0°. In-situ grown multi-scale SiO₂ NPs, perfluorooctyltriethoxysilane (FAS) brushes and dopamine can form a stable hierarchical surface which sustained superhydrophobicity/superoleophilicity when immersed in aqueous solutions at different pH values. Meanwhile, FAS brushes can serve as steric obstacles to efficiently repel water droplets during oil/water separation. The fabricated membrane possesses a high permeation flux and excellent separation properties (> 98%). In addition, this highly adhesive coating modification and hierarchical design can be widely applied on the surfaces of different materials, giving an attractive potential application prospect, such as oil/water separation, antifouling surface, and superwetting materials.

High-performance aromatic heterochain polymers are engineering thermoplastics with exceptional mechanical and thermal properties that have attracted great interest in various areas ranging from aerospace to biomedicine. However, there have been a number of difficulties to 3D-print materials based on such polymers with new promising performance characteristics. Herein, a number of new photosensitive compositions (PSCs) based on high-performance polyetherimide (PEI) or polysulfone (PSU), reactive functional monomer (N,N-dimethylacrylamide) and oligomer (bisphenol A ethoxylate diacrylate) has been developed. It has been shown that the use of the developed PSCs allows the formation of 3D-structures with high printing resolution by LCD 3D-printing. Subsequent thermal post-curing of 3D-printed green-state samples at 250°С for 1 h led to the fabrication of materials with the highest tensile strength (up to 41.9 ± 3.1 MPa), glass transition temperature (141 °C) and thermal stability (above 350 °C). In addition, 3D-printed structures demonstrate high-temperature shape memory effect with shape fixity ratio > 99% and shape recovery ratio up to 97.1%.

To enhance the anticorrosive performance of coatings in harsh corrosive environments, a graphene/isophorone diisocyanate (IPDI) microcapsule is prepared by in-situ polymerization. The self-healing and anticorrosive performance of coatings based on these microcapsules are studied. The microcapsule with cross-linked shells prepared in this study solves the problems of excessive size and insufficient strength of traditional microcapsules. The addition of microcapsules improves the anticorrosive performance of coatings. The shape of the microcapsules is in the form of round balls, and the average particle size and thickness of the microcapsules are in the range of 17–23 μm and 0.5–3.4 μm, which are conducive to the preparation of the coatings. The average strength of microcapsules is 20.64 MPa and the wrap-around rate reaches 68%. The microcapsules have an initial evaporation temperature of 231.3 °C， the graphene organic cross-linking shell enhances the strength and improves the thermal stability of microcapsules. The electrochemical impedance spectroscopy (EIS) indicates that the |Z|_{f=0.01 Hz} value of the coating with 10 wt% of microcapsule after 168 h of immersion is about 9.4 × 10⁹ Ω cm², nearly three orders of magnitude higher than that of the coating without microcapsule (6.9 × 10⁶ Ω cm²). Monitoring the artificial scratches of coating using a scanning electron microscope (SEM) for 24 h reveals that the microcapsule repairs the cracks well. It is demonstrated that the incorporation of graphene/IPDI microcapsules improves the anti-corrosive performance of the coating.

Magnetoactive polymer composites have garnered significant attention for their potential use in diverse applications, owing to their rapid and reversible response to external magnetic fields. By incorporating magnetic nanoparticles (MNPs) into an elastomeric matrix, these composites exhibit unique properties under static or alternating magnetic fields. In this context, thermo-polyurethane-based magnetic active composites are promising materials for developing microfluidic system components such as valves and peristaltic pumps. In the current study, we investigated the utilization of cobalt ferrite (CoFe₂O₄) magnetic nanoparticles in conjunction with a non-toxic synthesis method for polyurethane. It was explored the impact, on the overall success of the process, of cobalt ferrite nanoparticles incorporation at various stages of the thermo-polyurethane (TPU) synthesis reaction. Finally, the effects of different amounts of MNPs on the physicochemical properties of the resulting composites and their behavior as actuators under the influence of a magnetic field, was investigated. Our studies reveal that the actuator response of the composites increases proportionally with the percentage of MNPs present.

Finally, the performance of a TPU/7.5% (V/V) CoFe2O4 composite strip as a flow control actuator within a microfluidic system was evaluated. This actuator responds to magnetic fields by bending, resulting in a 10% reduction in flow rate of microfluidic system. Reversing the magnetic field restores the flow rate to its initial value. Our cyclic tests illustrate the actuator's capacity to locally and temporarily modulate the microfluidic system's resistance. When combined with tailored TPU elasticity, these materials show significant potential for the fabrication of microfluidic valves and pumps.

Alteration of chemical composition and chain topology of polymers allows for the rational regulation of their thermoresponsive behaviors. Compared with oxyether group, thioether moiety with higher hydrophobicity and oxidation sensitivity is proposed to present some differences in phase transition. To elucidate cyclization and thioether functionality dependent thermoresponsive behaviors, two pairs of thermo/pH/oxidation-responsive linear and cyclic Y-junction-bearing polymers (YJPs) involving dual thioether groups or coexistent thioether and oxyether moieties are designed. Multi-tunable LCST behavior can be achieved upon variations of hydrogen bonding, electrostatic and hydrophobic interactions. Owing to distinct stability of supramolecular interactions, copolymer solutions prepared by direct dispersion or self-assembly are liable to present a reverse order of phase transition temperature (T_c,l) relying on the thioether functionality. Cyclization of the backbone can result in an elevated T_c,l up to about 14 °C, revealing Y-junction-induced amplification of topology effect. T_c,l is prone to decreasing upon solvent switch from water to heavy water or pH increment, while the distinct oxidation sensitivity of monothioether and dithioether groups affords oxidation-triggered LCST “on/off” behaviors. In addition, intriguing sphere-to-vesicle-to-lamella-to-vesicle, vesicle-to-lamella-to-sphere and lamella-to-nanoribbon-to-lamella transitions occur in thermo-induced self-assembly. The success of this study paves the way for exploring thioether functionality dependent physicochemical properties and multipurpose applications of complex architectural polymers.

Cyclic polymers without chain ends have attracted increasing attention because of the unique physical properties. However, the direct visualization of cyclic topology remains a formidable challenge, because the cyclic chains with flexible backbone or strong intramolecular interaction usually existed in a coiled state rather than cyclic topology. Herein, monocyclic and bicyclic polymers were prepared via blocking-cyclization technique, and the molecular topology of cyclic polymer containing phenyl pendant was directly observed depending on the reduced intrachain entanglement. The structure and characteristics of cyclic polymers were investigated, and the difference between cyclic polymer and linear counterpart was demonstrated. Compared to linear polymer, cyclic polymer exhibited improved dielectric properties, and bicyclic polymer displayed further increased dielectric constant and energy storage density than monocyclic polymer possessing the same repeating units. Therefore, this research presents a facile strategy in the design and construction of cyclic polymers with directly visualized topology and unique dielectric properties.

In this contribution, we reported a novel strategy to crosslink polyurethane (PU) via host-guest inclusion complexations. First, a linear PU with adamantane (Ad) as side groups was synthesized with a 1,3-diol bearing adamantane as the chain extender. Thereafter, this linear PU was crosslinked with a poly(β-cyclodextrin) through host-guest inclusion complexations to afford PU-Ad-CD networks. In comparison with the linear PU, the PU-Ad-CD networks exhibited improved mechanical properties with the Young's modulus of 43.21 MPa, which was more than eight times as that of the linear PU. The formation of inclusion complexes enabled the PU-Ad-CD networks to display reprocessing properties. In addition, the shape memory properties of the networks featured the reconfigurability of original shape with the aid of the exchange of the host-guest inclusion complexations. This study provides new insights into the development of high-performance PU materials.

A series of supramolecular comb polymers (SCPs) with adhesive and healable characteristics have been generated through the copolymerisation of methacrylate monomers featuring aromatic amide functionalities with lauryl methacrylate. By varying the amide functionality and loading of the supramolecular monomers, the properties of the resulting SCPs can be tailored, ultimately providing stable films at room temperature. As the loading of the amide-bearing monomer was increased, the phase separation between the hard and soft domains was enhanced, promoting larger hard-domain aggregation, as observed via atomic force microscopy (AFM). The mechanical properties of the SCPs correlated to the loading of the amide-bearing monomers, by increasing the mol% incorporation the resulting SCPs transition from possessing high strain to high ultimate tensile strength (UTS) and Young's modulus (YM). Over several re-adhesion cycles, the SCPs were shown to retain their shear strength when thermally adhered to both glass and aluminium substrates. Additionally, the SCPs exhibited healable properties at elevated temperatures (> 45 °C) allowing for the recovery of mechanical properties post-damage.

Self-assembly of bottlebrush polymers are widely studied in photonic bandgap materials, biomedical materials and nanomaterial with different structures. In this work, high grafting density bottlebrush polymer with amphiphilic QPDMA[FeCl₄]-b-PS side chains grafting on every carbon atom of the backbone are prepared via grafting from approach. The para-isocyanobenzoate monomer modified with chain transfer agent (CTA) is designed and synthesized to prepared polymer backbones with CTA grafting on each atoms. The core-shell bottlebrush block copolymer is prepared by sequential reversible addition-fragmentation chain transfer polymerization of dimethylaminoethyl methacrylate and styrene. The inner core follows quaternization and ion exchange to form water soluble QPDMA[FeCl₄] magnetic block. The resulting core-shell bottlebrush magnetic polymer (PCN-g-[QPDMA[FeCl₄]-b-PS]) self-assembles into nanowires with magnetic QPDMA[FeCl₄] as core and PS as corona in the shell selected solvent dichloromethane, the length of nanowires increases with self-assembly time. While it self-assembles into nanoparticle clusters in core selected aqueous solution. And, the thermal and magnetic properties are affected by the self-assembly morphology. Especially, the as prepared PCN-g-[QPDMA[FeCl₄]-b-PS] and the nanoparticles cluster self-assembly are paramagnetic, but the nanowire self-assembly is superparamagnetic.

Polyester is widely used in biomedical, textile, and food packaging fields. Therefore, enhancing it with antimicrobial properties would be a significant advancement. In this paper, a series of borneol-triazine polyesters (BTPs) with different structures are synthesized through room temperature polycondensation. The structure and composition of BTPs are systematically characterized by ¹H NMR, FTIR and GPC. Antimicrobial results reveal that the ability of BTPs to resist bacterial or fungal adhesion is directly related to the polymer structure. When the polymer chain of BTPs adopts a rigid structure, they exhibit excellent anti-adhesive and inhibitory performances against both Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). Meanwhile, the as-synthesized BTPs poses a fungal-repelling effect on common fungal strains (Aspergillus niger) for up to 30 d. Further studies have shown that a stereochemical structure brought by borneol is key for imparting effective antimicrobial properties to BTPs. In addition, BTPs are non-leaching materials with low cellular cytotoxicity. Taking into consideration, BTP provides a potential strategy for preparing a new class of antimicrobial polyester materials.