Search Results (2,599)

Unsaturated polyester resins (UPRs) represent challenging systems for reversible-deactivation radical polymerization (RDRP) because chain propagation, branching, and localized gelation may occur concurrently. This study systematically investigates the influence of the concentration of the RAFT agent 2-cyano-2-propyl dodecyl trithiocarbonate (CPDT), the chemical structure of the polyester prepolymer, and the nature of the acidic comonomer on the structural evolution of RAFT-modified unsaturated polyester copolymers. Three copolymer series synthesized at different CPDT concentrations were investigated: p-EGM:AA:[CPDT], p-EGM:MAA:[CPDT], and p-PGM:MAA:[CPDT]. Structural changes were characterized using H NMR, H–H COSY, UV–Vis spectroscopy, and gel permeation chromatography (GPC). Semi-quantitative analysis of normalized H NMR integral intensities was performed using Relative Vinyl Intensity (RVI), CPDT-associated methyl intensity (MI*), and normalized aliphatic intensity (AI*) to compare changes in selected proton environments among the investigated copolymer series. Increasing CPDT concentration was accompanied by a decrease in the normalized residual maleate vinyl signal, although the magnitude of this change depended strongly on copolymer composition. The most pronounced decrease in RVI was observed for the p-EGM:AA:[CPDT] series, from 0.6291 to 0.0528, whereas substantially smaller changes were observed for the p-EGM:MAA:[CPDT] series. The MI* and AI* profiles exhibited composition-dependent variations, reflecting changes in the relative contributions of CPDT-associated methyl and overlapping aliphatic proton environments, respectively. Because the aliphatic region used for AI* contains overlapping polymer- and CPDT-derived contributions, AI* is not interpreted as a quantitative measure of polymer-backbone branching. Overall, the combined NMR and GPC/SEC results reveal composition-dependent structural changes accompanying RAFT copolymerization and demonstrate that both the polyester matrix and the acidic comonomer influence the response of these heterogeneous unsaturated polyester systems to variations in CPDT concentration. Full article

Absorbent pads are important materials for regulating exudate and local microenvironments in the packaging of high-moisture perishable foods. However, conventional absorbent pads often suffer from limited functionality, insufficient liquid retention, and a lack of active responsiveness. Hydrogels and aerogels, with tunable three-dimensional polymer networks, provide an important material basis for the design of new functional absorbent pads. This review focuses on the relationships among structure, function, and application, and compares hydrogels and aerogels in terms of network composition, crosslinking strategies, water absorption and retention mechanisms, and active compound loading and release behaviors. Structural design strategies, including multilayer structures, Janus structures, gradient pore structures, and micro/nano-reinforcement, are also summarized. On this basis, recent applications of hydrogel- and aerogel-based absorbent pads in the packaging of meat, aquatic products, fruits, vegetables, and edible fungi are discussed. Finally, the key challenges facing gel-based absorbent pads are analyzed, including adaptation to real food systems, release regulation, food-contact safety, and industrial-scale production. This review establishes a structure–function–application framework for gel-based absorbent pads and offers insights for designing sustainable active and intelligent food packaging. Full article

Future foods are driving an urgent need for sustainable and functional protein resources, and synthetic biology is emerging as a powerful platform to produce such proteins efficiently. Here, we designed a yeast protein (YP)–sanxan composite hydrogel obtained. The introduction of YP significantly improved thermal stability (by 5–15 °C) and ensured polymer compatibility. Rheological analysis indicated a frequency-dependent weak gel (tan δ = 0.1–0.3), making it suitable for safe swallowing. The material exhibited Type III nonlinear viscoelastic behavior, characterized by inter-cycle strain softening and a weak overshoot in G″, with Lissajous curves revealing a strain-induced transition from solid-like to fluid-like behavior. Crucially, YP-reinforced gels (5–20%) exhibited higher elastic moduli, indicating that the incorporation of YP strengthened the gel network and increased its structural rigidity, as further confirmed by Strain Sweep. With its tunable rheology and superior thermal stability, this hydrogel holds great potential for functional foods, 3D food printing, delivery systems, and biomedical scaffolds. Full article

Gene delivery with cationic polymers requires balancing DNA compaction, colloidal stability, and intracellular release, yet for imine-linked low-molecular-weight polyethyleneimine (PEI) vectors, quantitative relationships connecting the N/P ratio with the full property–transfection cascade remain undefined. Here, two amphiphilic non-viral vectors were prepared by linking a hydrophobic benzene–siloxane core (TAS) to hyperbranched PEI (800 or 2000 Da) through reversible imine bonds and complexed with DNA across a broad N/P range (10–600). Polyplexes were characterized by atomic force microscopy (AFM), dynamic light scattering (DLS), ζ-potential, agarose gel electrophoresis, transfection via green fluorescent protein (GFP) imaging and luciferase assay in HeLa cells. Both vectors formed spherical nano-entities (AFM diameters ~30 nm for TAS-PEI800; ~100 nm for TAS-PEI2000). TAS-PEI2000 achieved complete DNA retardation at N/P ≈ 30 versus N/P ≈ 150 for TAS-PEI800, consistent with its higher charge density (ζ = +37.59 vs. +18.35 mV). Transfection efficiency was superior for TAS-PEI2000 across most N/P ratios; however, TAS-PEI2000 displayed an optimal transfection efficiency at N/P ≈ 100 (ζ ≈ 3.84 mV), beyond which efficiency declined, indicating a binding–release trade-off. Cell viability remained >77% across the N/P range for TAS-PEI800, but dropped below 25% at N/P ≥ 400 for TAS-PEI2000. A phenomenological logistic model identified characteristic transition thresholds (θ ≈ 60 for TAS-PEI800; θ ≈ 40 for TAS-PEI2000), capturing the onset of cooperative self-assembly; however, the post-optimum decline observed for TAS-PEI2000 requires additional inhibitory terms. These findings demonstrate that PEI molecular weight governs both the N/P threshold required for efficient transfection and the width of the therapeutic window, thereby providing structure–activity descriptors for the rational design of imine-linked polyplex systems. Full article

Gadolinium-doped polymer gel dosimeters enable experimental evaluation of dose enhancement in low-energy radiotherapy, although the high Gd concentrations required substantially alter their magnetic relaxation properties, making the optimal Magnetic Resonance Imaging (MRI) readout uncertain. This study characterized the dosimetric response of PAGAT and Gd-PAGAT (9 mg/mL Gd) irradiated with a 150 kVp X-ray beam from 1 to 10 Gy using quantitative 1.5 T MRI. Quantitative R₁ and R₂ maps were obtained from variable flip-angle spoiled gradient echo (SPGR) and multi-echo spin echo (MSE) sequences, respectively, and validated by UV-Vis spectrophotometry. R₁ showed no significant dose dependence in Gd-PAGAT because of severe T₁ shortening. In contrast, R₂ exhibited a robust response, with second-order polynomial fits (R² = 0.9984 for PAGAT and 0.9969 for Gd-PAGAT) and linear behavior between 1 and 7 Gy. The dose sensitivity of Gd-PAGAT was 2.84 ± 0.19 times higher than that of PAGAT (0.5328 vs. 0.1949 s⁻¹·Gy⁻¹). Spectrophotometry confirmed the PAGAT calibration but showed markedly lower sensitivity for Gd-PAGAT, particularly at low doses. These findings demonstrate that R₂ mapping overcomes the limitations imposed by extreme T₁ shortening, extending the applicability of Gd-PAGAT dosimeters for three-dimensional dose enhancement studies in low-energy radiotherapy. Full article

This study investigates polymer/ionic liquid/polymer trilayer membranes for recovering aroma and fragrance compounds from a simplified synthetic model aqueous solution via pervaporation. The membranes featured organophilic polymer layers (PEBA and POMS) sandwiching an intermediate ionic liquid (IL) layer ([P₁₄₄₄][Tf₂N] and [Bmim][Tf₂N]), which were gelled with 12-hydroxystearic acid to ensure structural integrity. The trilayer architecture significantly enhanced separation performance compared with monophase membranes. The PEBA/[P₁₄₄₄][Tf₂N]/PEBA configuration achieved the highest enrichment factors, reaching 1626 for hexanal and 963 for linalool. Meanwhile, the POMS/[P₁₄₄₄][Tf₂N]/POMS system exhibited the highest selectivity relative to water. The introduction of the IL gel layer reduced overall mass transfer resistance while simultaneously suppressing water flux from 0.312 kg h⁻¹ m⁻² (in pure PEBA) to between 0.013 and 0.023 kg h⁻¹ m⁻². Overall, the results demonstrate that combining polymer matrices with gelled ILs in a trilayer design effectively optimizes mass transfer and selectivity, offering a promising strategy for the future valorization of aroma compounds from agro-industrial aqueous streams. Full article

Wound management continues to represent a major global healthcare challenge, with the wound care market growing each year and a rising incidence of chronic wounds worldwide. Effective wound healing requires dressings that protect injured tissue, prevent infection, and actively modulate the wound microenvironment to promote tissue regeneration. In recent years, smart polymeric wound dressings have emerged as a functional, more advanced class of wound dressings, engineered from materials capable of responding to stimuli. Physically responsive systems include moisture-adaptive dressings that prevent wound dryness or maceration, pressure-sensitive dressings incorporating flexible capacitive sensors for high mechanical stress mapping, thermoresponsive dressings exploiting sol–gel transitions for temperature-controlled drug release, light-responsive dressings enabling photothermal and photodynamic therapy, and electro-responsive dressings integrating conductive polymers for self-powered electrical stimulation or closed-loop wound monitoring. Chemically responsive systems exploit endogenous biochemical signals, including pH shifts for wound monitoring, reactive oxygen species-cleavable bonds for on-demand drug release, and glucose-responsive platforms for autonomous glycemic regulation in diabetic wounds. Biologically responsive dressings use enzymatic triggers, such as matrix metalloproteinases, hyaluronidase, and bacterial proteases, to achieve autonomous drug delivery. Film-forming sprays further expand the versatility of smart polymeric dressings by enabling contactless application adaptable to irregular wound shapes. In this review, we summarize recent advances in the design, stimuli-responsive mechanisms, characterization methods, and therapeutic outcomes of smart polymeric dressings for wound treatment. Despite promising preclinical results, challenges related to clinical translation, regulatory standardization, and scalable production remain and must be addressed to facilitate widespread clinical adoption. Future directions include multi-stimuli responsive platforms, artificial intelligence-guided wound monitoring, bioprinting of specific dressings, and environmentally sustainable biomaterial design. Full article

With the continuous expansion of ultra-deep and deep well drilling toward complex geological formations, the performance stability of water-based drilling fluids and wellbore stability under ultra-high temperature and high-salinity conditions have become critical challenges. High temperature and salt contamination can induce the degradation or failure of drilling fluid additives, while the development of pores and fractures in complex formations further increases the risk of filtrate invasion. Conventional polymer and inorganic plugging agents often suffer from insufficient thermal stability, poor salt tolerance, or limited adaptability to complex pore structures. In this study, an organic–inorganic hybrid gel microsphere plugging agent (HGP) with a core–shell structure was developed by in situ polymerization of AMPS, styrene (St), and sodium styrene sulfonate (SSS) on KH570-modified nano-SiO₂. The hybrid microspheres consisted of a rigid SiO₂ core and a flexible polymer shell, providing synergistic thermal stability, mechanical strength, and deformation capability. Structural characterization confirmed the successful formation of the designed organic–inorganic hybrid structure. After aging at 240 °C, HGP maintained stable morphology and dispersion characteristics, while exerting minimal influence on drilling fluid rheological properties. The addition of 3 wt% HGP reduced API fluid loss by approximately 30% and decreased sand bed invasion by approximately 50% after high-temperature aging. Under 35 wt% NaCl and 5 wt% CaCl₂ contamination, HGP maintained effective filtration control, reducing fluid loss by more than 50% compared with the base fluid. Furthermore, HGP achieved core plugging efficiencies above 94% and reduced mud cake permeability by over 70%, demonstrating superior plugging performance compared with polymer microspheres NF-1 and SiO₂ particles. The enhanced performance was considered to arise from the synergistic effects of stable dispersion, pore-throat bridging, deformation filling, and structural stabilization. This study provides a rigid–flexible hybrid strategy for designing high-performance plugging agents for ultra-high temperature and high-salinity water-based drilling fluids. Full article

As critical infrastructure for carbon capture, utilization, and storage (CCUS) and large-scale energy storage, subsurface salt caverns are seriously challenged by fluid-induced sediment mobilization during the supplementary debrining. Conventional bulk resin consolidation often causes severe viscous fingering, uneven consolidation, and pore clogging under hypersaline conditions. Here, we develop a foam-templated hybrid polymer gel co-stabilized by silica nanoparticles, polyvinyl alcohol, and the zwitterionic surfactant. The key novelty is the use of foam as a transient transport template that redistributes the resin phase and promotes selective cementation at grain-contact points instead of indiscriminate pore filling. This nano-reinforced gel system remained stable under hypersaline conditions (24% NaCl), and temperatures ranging from 20–80 °C. Micro-CT analysis showed that this selective templating preserved an interconnected pore network with a porosity above 45% and a CT-derived permeability of approximately 1.18 D, while reducing binder consumption by 55.6% relative to bulk resin injection. Crucially, a 1:200 geometrically scaled, velocity-matched pilot model demonstrated that this gel strategy limited sediment entrainment below 0.5% and reduced fluid discharge by 45.9%. These results establish a material-efficient consolidation strategy that combines sediment stabilization with permeability preservation, providing a promising solution for safer supplementary debrining in salt-cavern CCUS and energy-storage operations. Full article

Recently, gel coatings have been studied as a promising method that can provide electrochemical corrosion protection. This review presents a comprehensive analysis of advanced gels such as sol–gel coatings, hybrid organic–inorganic, self-healing, and crack repair gels. These gels employ different mechanisms for corrosion protection, from passive barrier formation to active self-healing and corrosion inhibition. Their performance can be influenced by gel chemistry, microstructure, and the incorporation of functional additives. Recent studies have shown that gel coatings can achieve promising corrosion resistance. This high efficiency can be attributed to the formation of dense barrier layers that restrict the mobility of attacking ions. The incorporation of functional additives such as silica nanoparticles can enhance mechanical characteristics for gels. In the field of crack-repair, bio-gels based on microbially induced calcium carbonate precipitation show acceptable sealing capability. Additionally, the evolution of polarization resistance and corrosion current suggests the sustained protective performance of these gels. Multifunctional gels extend this concept by combining crack sealing, alkalinity restoration, and steel re-passivation. Gel coatings are transitioning from simple barrier coatings to multifunctional smart inhibition capable of self-healing, corrosion sensing, and long-term durability. This review highlights the relationship between gel chemistry, microstructure, and corrosion resistance for the development of next-generation gel coatings. Full article

Liquid water in hydrogels exhibits an adsorption-desorption dynamic equilibrium with the surrounding environment, which leads to the instability of mechanical properties. To address this limitation, we propose an innovative design of conductive composite organogels by incorporating compatible linear lauryl alcohol (LA) and multi-walled carbon nanotubes (CNTs) into a poly(butyl methacrylate) (PBMA) network. Carbon chains of LAform physical crosslinks with PBMA side chains, effectively replacing inherent polymer chain entanglements. This structural innovation facilitates rapid chain rotation and sliding during stretching, so that the gel has a super stretching property of up to 2460%. At elevated temperatures, weakened interactions between LA–PBMA and PBMA–PBMA chains reduce physical confinement of CNTs within the PBMA network. Simultaneously applying a directional electric field, CNTs undergo rotation and translation to reconstruct an optimized conductive pathway, granting the composite distinctive temperature-sensitive electrical conductivity. Critically, all components in the PBMA/LA/CNTs (PLCs) exhibit low volatility and hydrophobicity. These characteristics enable the organogel to retain excellent flexibility and stable electrical performance after prolonged immersion in deionized water, exposure to vacuum, and even under extreme conditions at 120 °C. Such comprehensive stability suggests promising applications in deep-sea exploration and aerospace engineering. Full article

Multifunctional polymer scaffolds with mechanical support, biocompatibility, and antimicrobial activity are key for next-generation biomedical materials. We report the fabrication of electrospun nanocomposite fibers made from polycaprolactone (PCL), starch, and mesoporous aluminum oxide nanoparticles (n-Al₂O₃). Nanoparticles (11 ± 4 nm) were synthesized via a sol-gel method, predominantly comprising γ- and α-Al₂O₃ phases. Four fiber systems were fabricated by side-by-side electrospinning: PCL, PCL/starch, PCL/n-Al₂O₃, and PCL/starch/n-Al₂O₃. SEM analysis confirmed uniform and bead-free fibers in all formulations. Tensile tests showed that the incorporation of starch and nanoparticles improved the mechanical performance compared with neat PCL. In particular, PCL/starch/n-Al₂O₃ fibers exhibited increases of 404% in Young’s modulus and 102% in elongation at break. In PBS, starch and n-Al₂O₃ enhanced hydrophilicity and accelerated weight loss, with PCL/starch/n-Al₂O₃ showing the highest mass loss. Antibacterial tests indicated that only fibers with nanoparticles could inhibit Staphylococcus aureus and Escherichia coli, with PCL/starch/n-Al₂O₃ showing a major effect. Although n-Al₂O₃ increased cytotoxicity toward NIH-3T3, starch mitigated this effect, and the ternary scaffold showed no detectable cytotoxicity. Moreover, PCL/starch/n-Al₂O₃ exhibited non-hemolytic behavior, enhanced fibroblast migration, and wound-healing-related protein expression. Overall, side-by-side electrospun PCL/starch/n-Al₂O₃ scaffold exhibited showed improved mechanical, biological, and antibacterial properties, supporting its potential as a wound-dressing material. Full article

Ion-imprinted polymers (IIPs) are advanced adsorbents featuring selective recognition cavities for targeted metal ion capture, offering a promising route to high-efficiency separation in extractive metallurgy. In the present work, the evolution, design principles, synthesis strategies, separation mechanisms, and practical applicability of IIPs for metal recovery from complex aqueous matrices are overviewed. Key material components, including functional monomers, crosslinkers, template ions, initiators, solvents, and support materials, are discussed in relation to adsorption capacity, selectivity, kinetics, stability, and recyclability. Major preparation routes, such as surface imprinting, bulk polymerization, in situ polymerization, and sol–gel methods, are critically compared to clarify their advantages and limitations. Recent applications for base metals, precious metals, and rare-earth elements demonstrate that IIPs can achieve high specificity and rapid equilibrium under optimized conditions. However, their translation from simulated solutions to real leachates remains constrained by interfering ions, organic contaminants, mass transfer resistance, incomplete template removal, and matrix complexity. Mitigation strategies, including sample pretreatment, improved polymer architecture, and hybrid supports, are therefore emphasized. Additionally, chemometric modelling, machine learning, or artificial intelligence-assisted design may be implemented to advance the prospects of IIPs in industry. Conclusively, IIPs represent a strong separation platform, yet industrial deployment requires robust validation with real feed streams and scalable regeneration protocols during column operation, as well as under chemically aggressive conditions at scale. Full article

In this study, we evaluated the influence of physicochemical aging on the biological processing and depolymerization performance of polyethylene (PE) and polylactic acid (PLA) by Tenebrio molitor larvae, with the goal of improving insect-based plastic treatment strategies. PE and PLA subjected to a sequential freezing–ultraviolet aging protocol showed modest increases in total larval consumption (approximately 11% for PE and 10% for PLA) compared with pristine materials. Aging also accelerated the processes related to chemical depolymerization, as evidenced by Fourier transform infrared spectroscopy and scanning electron microscopy showing the formation of oxidized functional groups and surface structural deterioration, respectively. Gel permeation chromatography indicated significant reductions in molecular weight. In addition, thermogravimetric analysis was used to evaluate the changes in thermal stability associated with polymer degradation. Gut microbiome analysis revealed that plastic diets and aging collectively shaped microbial structure and compositional shifts, with deterministic ecological processes dominating community assembly. PE diets enriched Proteobacteria, while PLA diets enriched Firmicutes and Desulfobacterota. Notably, aging strengthened microbial cooperation and enriched key genera, such as Spiroplasma sp. and Lactobacillus sp., which are potentially associated with plastic-associated metabolic adaptation. Overall, aging modestly facilitated larval processing and partial depolymerization of both fossil-based and bio-based plastics, as reflected by increased plastic consumption, polymer chain scission, and surface oxidation. It also enhanced the functional robustness of the larval gut microbiome. These findings provide mechanistic insights into insect-mediated plastic processing systems, offering mechanistic guidance for future, combined plastic treatment strategies rather than an immediately scalable stand-alone solution. Full article

Excessive water production remains one of the most intractable challenges threatening the economic and sustainable development of oil production worldwide. In situ crosslinking polymer gel systems have been widely adopted as cost-effective chemical solutions for water shutoff and conformance control in oilfields. However, the excessively fast gelation kinetics of conventional gel systems at elevated temperatures severely hinders their application in deep, high-temperature reservoirs. To address this gap, this work systematically evaluates a novel Cobalt(II) (Co(II))-crosslinked polymer gel system developed for water control in high-temperature reservoirs. The effects of polymer type, Co(II) concentration, salinity, temperature, and pH on the gelation time, sol–gel transition behavior, and long-term thermal stability of the system were comprehensively investigated. Compared with the most widely used Cr(III)-crosslinked polymer gel systems, the Co(II)-based gel system exhibits a significantly prolonged gelation time at 130 °C, and the gelation time is positively correlated with the molar content of 2-acrylamido-2-methyl propane sulfonate (AMPS) in the polymer backbone. For instance, the gelation time at 130 °C can be remarkably delayed to 16 days when using the AMPS-rich polymer SAV-10. A unique and distinguishing feature of this polymer/Co(II) gel system is its fully reversible thermoresponsive sol–gel transition behavior. Unlike Cr(III)- and Zr(IV)-crosslinked gels, which form permanent and irreversible gels once crosslinked, the Co(II)-based gel system can crosslink into a robust bulk gel at high temperatures and reversibly switch back to a low-viscosity polymer solution when the temperature drops. For example, the SAV-28/Co(II) mixture forms a stable gel at 130 °C and fully reverts to a flowing polymer solution when the temperature is reduced to 80–85 °C. Furthermore, the SAV-10/Co(II) gel exhibits exceptional long-term thermal stability at 130 °C in both 5% NaCl brine and reservoir formation water, with no observable gel volume loss or syneresis after 100 days of high-temperature aging. The combination of tunable delayed gelation, unique thermoreversible sol–gel transition, and excellent high-temperature stability makes this Co(II)-based gel system a promising candidate for water control in oil and geothermal reservoirs, particularly for targeted plugging in the far-wellbore region and other advanced applications requiring dynamic and reversible fluid diversion. Full article