Rapid preparation of composite hydrogels typically relies on external energy input, forcing a compromise among fabrication simplicity, mechanical durability, and biological functionality. Herein, a redox-active quercetin-Fe3+ (QCT-Fe3+) coordination complex is designed to address this conflict, acting simultaneously as a mild catalyst and an active functional component. QCT-Fe3+ mediated activation of ammonium persulfate enables acrylic acid polymerization in ∼5 s without ultraviolet light or external heating. After optimizing the QCT:Fe3+ ratio and the Fe3+ concentration, chitosan was incorporated to form a poly(acrylic acid)/chitosan composite hydrogel, which gelated in 21.0 ± 1.6 s at room temperature. This hydrogel exhibited a tensile modulus of 103.09 ± 4.98 kPa and an equilibrium swelling ratio of 193.91 ± 11.60% and retained ∼88.7% of its peak stress after 500 consecutive loading–unloading cycles. Multiple interfacial interactions render firm adhesion with wet tissues (63.11 ± 4.00 kPa on porcine skin and 19.31 ± 2.40 kPa on porcine subcutaneous fat). The strain-dependent electrical response, with a gauge factor of up to 2.54, enables conformal monitoring of finger, elbow, and knee movements. Sustained QCT-Fe3+ complex release over 168 h endows the hydrogel with radical-scavenging ability and antibacterial activity. The hydrogel suppresses fibroblasts proliferation and migration selectively while remaining compatible with myoblasts, suggesting potential for wound status monitoring and antifibrotic application. By coupling rapid network formation with mechanical, sensing, and biological functions through a single metal-polyphenol coordination motif, this study provides a versatile strategy for engineering multifunctional hydrogel biointerfaces.
Melamine-formaldehyde (MF) resin microspheres show great promise as high-performance adsorbents for the purification of wet electronic chemicals. However, their reliance on formaldehyde introduces severe toxicity risks and leads to free aldehyde leaching that contaminates the purification process. In this work, glutaraldehyde was employed to completely replace formaldehyde for the preparation of melamine resin microspheres via a facile suspension polymerization process. The preparation parameters (such as feed molar ratio, polymerization temperature, and the oil–water ratio) were systematically optimized to regulate the morphology, particle size, and specific surface area. The physicochemical properties of the as-prepared microspheres were comprehensively characterized via scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), nitrogen adsorption–desorption isotherms, thermogravimetric analysis (TGA), and swelling resistance tests. The results indicate that the optimized glutaraldehyde-cross-linked melamine resin microspheres exhibit a regular spherical morphology, a narrow particle size distribution, adequate thermal stability for engineering applications, and a low swelling ratio in wet electronic chemical media without leaching of free glutaraldehyde. The adsorption of Cu, Fe, and Ti ions in a propylene glycol methyl ether/propylene glycol methyl ether acetate (PGME/PGMEA) photoresist thinner was investigated via isotherm, kinetic, and cyclic reusability studies. The adsorption data are well fitted by the Langmuir–Freundlich isotherm and pseudo-second-order kinetic models, revealing a mixed monolayer-multilayer chemisorption mechanism. The maximum adsorption capacity for various ions ranged from 4405.21 to 5298.43 μg/g, and the microspheres maintained a decrease in adsorption efficiency of no more than 15.8% after five regeneration cycles. This work offers a green, scalable synthesis strategy and sheds light on the advanced purification of high-purity wet electronic chemicals.
High-density polyethylene (PE) plays a central role in polymer composite materials due to its excellent mechanical properties, ease of processing, and low cost. In the quest for more sustainable materials, biosourced fillers like microgranular cellulose (MGC) have emerged as a promising alternative to conventional reinforcements. MGC is particularly attractive because it is mechanically extracted from cotton waste and requires little to no chemical pretreatment. In this study, we harnessed dynamic covalent chemistry to enhance the thermomechanical properties of PE/MGC composites while maintaining mechanical recyclability. Samples were prepared by reactive extrusion of PE and MGC (20 wt %) in the presence of an azidotriazine grafting agent (1 wt %), and the influence of the extrusion conditions on the microstructure and thermomechanical properties was investigated. The resulting materials exhibit a higher Young’s modulus and yield stress than virgin PE, with elongation at break values varying according to the processing conditions. Morphological analysis via scanning electron microscopy, combined with energy-dispersive X-ray spectroscopy and selective cellulose dissolution, revealed how the processing conditions dictate the microstructure and filler dispersion within the PE matrix. The mechanical recyclability of the composites was evaluated, with most thermomechanical properties retained after reprocessing. Composites containing 40 wt % of MGC were also prepared. These materials exhibit a strongly improved Young’s modulus, yield stress, and creep resistance compared to PE, all while incorporating a large proportion of cellulose extracted from cotton waste.
Abstract Developing multifunctional synthetic textiles via inorganic nanoparticle modification has long presented a formidable challenge due to particle agglomeration and matrix incompatibility. This study utilized a surface dissolution strategy to immobilize flower-shaped CNC/ZnO onto PET yarns. This method reduced particle aggregation and promoted the distribution of CNC/ZnO on PET yarns. Morphological observations confirmed that the flower-shaped ZnO architectures provided abundant scattering interfaces. The CNC/ZnO-PET fabric simultaneously achieved enhanced solar reflectance and high mid-infrared emissivity within the 8–13 μm atmospheric window. Outdoor thermal measurements demonstrated that the CNC/ZnO-PET fabric exhibited an improved cooling response, maintaining an internal temperature 2.5 °C lower than that of original PET under direct sunlight. The maximum temperature difference between the original PET and CNC/ZnO-PET fabrics reached 7.7 °C. In addition, the modified fabric exhibited a UPF of 134.4 and showed antibacterial rates of 99.90% against both Escherichia coli and Staphylococcus aureus. After 10 washing cycles, the fabric retained good solar reflectance, UV protection, and antibacterial performance. These results demonstrate the potential of surface dissolution for preparing multifunctional PET textiles with UV protection, radiative cooling, and antibacterial properties, particularly for outdoor shading applications.
Abstract Physical polysaccharide–protein hydrogels can load and release volatile actives, but how these additives affect the network structure, mechanics, and transport remains unclear. Noncontact active packaging also requires controlled, sustained release. κ-Carrageenan/gelatin (κ-cg/gel) hydrogels incorporating essential oils (EOs) were prepared by cooling-induced physical gelation to investigate how the oils influence network properties and volatile release. FTIR and 1H NMR data are compatible with intermolecular association (hydrogen bonding and electrostatic interactions) between the biopolymers, and FESEM of freeze-dried samples showed more open microstructures in EO-loaded gels. EO loading increased the storage modulus, compressive resistance, elastic recovery, and water retention, which is interpreted as EO-induced network reinforcement. The apparent mesh size estimated from the storage modulus decreased from about 21 to 15 nm. The hydrogels provided sustained oil release for up to 168 h (7 days), with diffusion-controlled, non-Fickian transport that fit the Higuchi and Korsmeyer–Peppas models. The κ-cg/gel-(3:1) formulation with coffee EO performed best, yielding >90% repellency of the pharaoh ant (Monomorium pharaonis, a model pest) at 24 h while retaining structural integrity under cyclic loading. Antimicrobial and antioxidant activity, surface wettability, vapor-barrier properties, and food-storage performance were not evaluated; the system is therefore presented as a promising noncontact EO reservoir that warrants further testing toward bioactive food packaging.
