Search Results (127)

Waterproofing systems frequently experience performance degradation during long-term service due to material aging and structural deformation, thereby necessitating localized repair interventions. The bonding interface between newly applied and existing membrane materials is a critical determinant of repair effectiveness. In this study, the aging-dependent repair performance of three representative waterproof membrane systems was systematically investigated using peel strength testing, low-temperature flexibility assessment, and interfacial morphology analysis under thermal–oxidative aging for 2, 5, 14, and 28 days. The results demonstrate that the homogeneous repair system based on ultra-thin reinforced self-adhesive polymer-modified bituminous membranes exhibits superior overall performance, maintaining the highest peel strength with only minor degradation even after 28 days of accelerated aging. In contrast, the polymeric butyl self-adhesive membrane subjected to homogeneous repair exhibited rapid adhesion degradation after 14 days, whereas the heterogeneous repair system showed improved stability during intermediate aging stages. Low-temperature flexibility testing further revealed that root-resistant bituminous membranes exhibited a slower aging rate, with a cracking temperature increase of 7 °C after 28 days, compared to a 10 °C increase observed for ultra-thin self-adhesive membranes. These quantitative findings provide clear guidance for the selection of appropriate repair membrane systems under varying aging conditions in waterproofing engineering, particularly for maintenance and rehabilitation applications. Full article

Granular copper oxide nanoparticles (CopOx NPs), synthesized via laser ablation (100 nm, ζ-potential +30 mV), were introduced into photolithographic polymethyl methacrylate (PMMA) resin at concentrations of 0.001–0.1%. The resulting composite material enables the fabrication of high-resolution (up to 50 μm) parts with a high degree of surface quality after polishing using the MSLA method. CopOx NPs increased the degree of resin polymerization (decrease by almost 4× in unpolymerized components at 0.1% CopOx NPs) and induced the in situ formation of self-organized periodic structures visible under a modulation interference microscope. The composite samples exhibit pronounced oxidative activity: they intensify the generation of hydrogen peroxide and hydroxyl radicals and cause the oxidative modification of biomolecules (formation of 8-oxoguanine in DNA and long-lived reactive forms of proteins). A key property of the materials is their selective biological activity. While lacking cytotoxicity for human fibroblasts, they exhibit a strong antibacterial effect against E. coli, leading to cell death within 24 h. Thus, the developed composite photolithographic resin combines improved technological characteristics (high printing resolution, degree of polymerization) with functional properties (selective antibacterial activity) and holds promise for application in biomedicine, as well as in the food and agricultural industries. Full article

Microalgae are considered to be a dual solution for CO₂ fixation and biogas slurry purification due to their high photosynthetic efficiency and strong environmental adaptability. However, their application is constrained by the low solubility of CO₂ in the solution environment, which restricts microalgal growth, resulting in low biomass production and poor slurry purification efficiency. In this study, we developed MgFe layered double hydroxide (LDH) that spontaneously combined with Chlorella pyrenoidosa to help it concentrate CO₂, thereby increasing biomass yield and purification capacity for food waste biogas slurry. The prepared MgFe-LDH exhibited a typical layered structure with a CO₂ adsorption capacity of 4.44 mmol/g. MgFe-LDH and C. pyrenoidosa carried opposite charges, enabling successful self-assembly via electrostatic interaction. Compared with the control, the addition of 200 ppm MgFe-LDH increased C. pyrenoidosa biomass and pigment content by 36.82% and 63.05%, respectively. The removal efficiencies of total nitrogen, total phosphorus, and ammonia nitrogen in the slurry were enhanced by 20.04%, 31.54% and 14.57%, respectively. The addition of LDH effectively alleviated oxidative stress in C. pyrenoidosa and stimulated the secretion of extracellular polymeric substances, thereby enhancing the stress resistance and pollutant adsorption capabilities. These findings provided a new strategy for the industrial application of microalgal technology in CO₂ fixation and wastewater treatment. Full article

Poly(ε-caprolactone)-b-polysarcosine (PCL-b-PSar) block copolymers (BCPs) emerge as a promising alternative to conventional poly(ε-caprolactone)-b-poly(ethylene oxide) BCPs for biomedical applications, leveraging superior biocompatibility and biodegradability. In this study, we synthesized two series of PCL-b-PSar BCPs with controlled polymerization degrees (DP of PCL: 45/67; DP of PSar: 28–99) and low polydispersity indexes (Đ ≤ 1.1) and systematically investigated their crystallization-driven self-assembly (CDSA) in alcohol solvents (ethanol, n-butanol, and n-hexanol). It was found that the limited solubility of PSar in alcohols resulted in competition between micellization and crystallization during self-assembly of PCL-b-PSar, and thus coexistence of lamellae and spherical micelles. To overcome this morphological heterogeneity, we developed a modified self-seeding method by employing a two-step crystallization strategy (i.e., T_c1 = 33 °C and T_c2 = 8 °C), achieving conversion of micelles into crystals and yielding uniform self-assembled structures. PCL-b-PSar BCPs with short PSar blocks tended to form well-defined two-dimensional lamellar crystals, while those with long PSar blocks induced formation of hierarchical structures in the PCL₄₅ series and polymer aggregation on crystal surfaces in the PCL₆₇ series. Solvent quality notably influenced the self-assembly pathways of PCL₄₅-b-PSar₂₈. Lamellar crystals were formed in ethanol and n-butanol, but micrometer-scale dendritic aggregates were generated in n-hexanol, primarily due to a significant Hansen solubility parameter mismatch. This study elucidated the CDSA mechanism of PCL-b-PSar in alcohols, enabling precise structural control for biomedical applications. Full article

Liquid metals (LMs), with their unique combination of high electrical conductivity and mechanical deformability, have emerged as promising materials for stretchable electronics and biointerfaces. However, the practical application of bulk LMs in wearable sensors has been hindered by processing challenges and low stability. To overcome these limitations, liquid metal particles (LMPs) encapsulated by native oxide shells have gained attention as versatile and stable fillers for stretchable and conductive composites. Recent advances have focused on the development of LM-based hybrid composites that combine LMPs with metal, carbon, or polymeric fillers. These systems offer enhanced electrical and mechanical properties and can form conductive networks without the need for additional sintering processes. They also impart composites with multiple functions such as self-healing, electromagnetic interference shielding, and recyclability. Hence, the present review summarizes the fabrication methods and functional properties of LM-based composites, with a particular focus on their applications in wearable sensing. In addition, recent developments in the use of LM composites for physical motion monitoring (e.g., strain and pressure sensing) and electrophysiological signal recording (e.g., EMG and ECG) are presented, and the key challenges and opportunities for next-generation wearable platforms are discussed. Full article

Composite solid propellants, which serve as the core energetic materials in aerospace and military propulsion systems, necessitate tailored enhancement of their mechanical properties to ensure operational safety and stability. A critical challenge involves elucidating the interfacial interactions among the multiple propellant components (≥6 components, including the polymer binder HTPB, curing agent IPDI, oxidizer particles AP/Al, bonding agents MAPO/T313, plasticizer DOS, etc.) and their influence on crosslinked network formation. In this study, we propose an integrated computational framework that combines coarse-grained simulations with reactive force fields to investigate these complex interactions at the molecular level. Our approach successfully elucidates the two-step reaction mechanism propagating along the AP interface in multicomponent propellants, comprising interfacial self-polymerization of bonding agents followed by the participation of curing agents in crosslinked network formation. Furthermore, we assess the mechanical performance through tensile simulations, systematically investigating both defect formation near the interface and the influence of key parameters, including the self-polymerization time, HTPB chain length, and IPDI content. Our results indicate that the rational selection of parameters enables the optimization of mechanical properties (e.g., ~20% synchronous improvement in tensile modulus and strength, achieved by selecting a side-chain ratio of 20%, a DOS molar ratio of 2.5%, a MAPO:T313 ratio of 1:2, a self-polymerization MAPO time of 260 ns, etc.). Overall, this study provides molecular-level insights into the structure–property relationships of composite propellants and offers a valuable computational framework for guided formulation optimization in propellant manufacturing. Full article

Durable polyamidoamine (PAA) coatings were covalently grafted onto cotton by applying a water-soluble, glycine-based PAA (M-GLY) through a radical polymerization mechanism. M-GLY oligomers of different chain lengths, terminated with bisacrylamide groups, were synthesized via polyaddition of N,N′-methylenebisacrylamide and glycine at molar ratios of 1:0.9, 1:0.85, and 1:0.8. Cotton strips were then impregnated with differently concentrated (10 and 20 wt.%) aqueous solutions of the M-GLY oligomers in the presence of potassium persulfate, which oxidized cellulose and generated radicals that initiated polymerization of the M-GLY terminals, thereby enabling covalent grafting onto cotton. This process yielded M-GLY-grafted cotton (COT-g-M-GLY) with 2–15% add-on levels. Scanning electron microscopy revealed uniform surface coverage and penetration of the coating into fiber interiors. Grafting did not alter cellulose crystallinity—65% vs. 64% for grafted and virgin cotton. However, thermogravimetric analysis showed that COT-g-M-GLY exhibited lower thermo-oxidative stability than M-GLY-adsorbed cotton (COT/M-GLY) at similar add-ons. Flame-retardancy tests indicated that COT-g-M-GLY reduced the burning rate (by 10% to 30%) but did not achieve self-extinguishing behavior, unlike COT/M-GLY. Despite this, COT-g-M-GLY provided good protection against UV-induced photodegradation. After accelerated UVA–UVB exposure, cotton samples with 10% M-GLY add-on showed a significantly reduced yellowing rate compared to untreated cotton, as confirmed by spectrophotometric analysis. Full article

Localized treatment has emerged as an excellent alternative to minimize the side effects associated with the systemic dispersion of therapeutic agents, which can damage healthy tissues. Injectable hydrogels offer a promising solution because they can encapsulate and release therapeutic agents in a controlled manner. In this context, this study focuses on the development and characterization of an injectable hydrogel based on carboxymethyl chitosan (CMCh) and oxidized agarose (OA), in which chemical crosslinking through imine bond formation avoids the use of external crosslinking agents. Several polymer ratios were evaluated to obtain hydrogels (OA:CMCh), and stable gels were formed at physiological temperatures in all cases. The hydrogels were injectable through a 21 G needle with forces below 30 N, formed porous structures, and exhibited a self-healing capacity after 48 h. Additionally, the hydrogels displayed compressive strengths ranging from 26 to 71 kPa and elastic moduli similar to those of human tissues (6–20 kPa). Swelling percentages of up to 3090% were achieved owing to the high hydrophilicity of CMCh and OA, and strong chemical crosslinking maintained the gel stability for two weeks with low mass loss rates (<21%). Furthermore, polymer ratio variation and storage at 4 °C were observed to affect the hydrogel characteristics, allowing for property modulation according to the application needs. These results indicate that the proposed polymeric combination enables the formation of hydrogels with the potential for localized drug delivery. Full article

The development of self-healing coatings represents a promising approach to enhance the durability of metal substrates exposed to corrosive environments, demanding thorough in situ investigations. In this study, poly(urea–formaldehyde–melamine) (PUF) microcapsules containing linseed oil (LO) were synthesized via in situ polymerization to act as healing agents in protective coatings. The microcapsules were characterized using scanning electron microscopy (SEM), optical microscopy (OM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The capsules exhibited a regular spherical morphology with an average diameter of 96 µm and an LO encapsulation efficiency of 81 wt%. TGA confirmed their thermal stability up to 200 °C, while FTIR verified the successful encapsulation of LO. For performance evaluation, 10 wt% of the microcapsules was incorporated into an epoxy matrix and applied to carbon steel. Corrosion resistance was evaluated using electrochemical impedance spectroscopy (EIS) in 0.1 mol/L of NaCl solution over 500 h. The coating with microcapsules exhibited a |Z|_0.01 of 10⁶ Ω·cm², higher than the 10⁴ Ω·cm² observed for the coating without microcapsules, indicating improved barrier properties. Raman spectroscopy confirmed the auto-oxidation of LO at damaged areas, evidencing the self-healing mechanism. Although full barrier recovery was not achieved, the system effectively delayed corrosion progression. Full article

Carbon dioxide-based copolymers such as polypropylene carbonate (PPC) can offer the double environmental benefit of capturing CO₂ and replacing oil-based raw materials in the plastics industry with renewable ones. However, their production at an industrial level is still limited by the range of applications in which their physicochemical properties are competitive and ideally surpass those of fossil-based polymeric commodities. This work introduces PPC materials with high-stretch and self-healing properties that were prepared by copolymerization of CO₂ and propylene oxide using tailored Zn glutarate catalysts. The PPC materials were analyzed in terms of composition, molecular weight, thermal and mechanical behavior, particularly focusing on their tensile properties, strain recovery, creep response, and self-healing ability. All the prepared PPC materials showed good ductility and self-healing properties. The most promising ones achieved excellent and fast recovery of extremely high elongations (>700%), still reaching remarkable values (>600%) after proper self-healing. These high-stretch and self-healing PPC materials are completely amorphous, present good optical transparency, and can be processed using techniques normally used for other thermoplastics. Therefore, they are promising for a variety of applications, including shrink films and self-healing packaging, thus providing new, valuable perspectives for the industrialization of these CO₂-based polymers. Full article

Background: Ulcerative colitis (UC), a subtype of chronic inflammatory bowel disease (IBD), is primarily treated with oral medications to reduce inflammation and alleviate symptoms. Celecoxib (CXB) is an attractive candidate for UC; however, its limited solubility and low bioavailability pose significant challenges to its clinical application. Methods: We reported a novel chondroitin sulfate A–Celecoxib (CSA-CXB) polymeric nanoprodrug to address the limited solubility and low bioavailability of CXB. CXB was conjugated to chondroitin sulfate A (CSA) via succinic anhydride (SA) and ethylenediamine to prepare CSA-CXB polymers, which can self-assemble into nanoparticle structural prodrugs in aqueous condition. We investigated the stability, blood compatibility, and responsiveness of the nanoparticles. The ability of the nanoparticles to treat UC in vitro and in vivo was then evaluated. Results: The CSA-CXB nanoprodrug was spherical with a mean particle size of 188.4 ± 2.2 nm, a zeta potential of −22.9 ± 0.1 mV, and sustained drug release behavior. Furthermore, CSA-CXB exhibited remarkable antioxidant and anti-inflammatory effects, as it can significantly increase the free radical scavenging rate and reduce the expression level of ROS, TNF-α, IL-6, nitric oxide (NO), and COX-2 protein in vitro. In vivo results demonstrated that CSA-CXB targeted the mice’s colon efficiently mitigate UC symptoms by inhibiting the expression of inflammatory cytokine. Conclusions: The CSA-CXB nanoprodrug can improve the therapeutic impact of CXB, and has potential as a new preparation for a clinical UC treatment nanoprodrug. Full article

Amphiphilic block copolymers with complex topologies (e.g., star and brush topologies) have attracted significant attention in drug delivery owing to their superior performance over linear micelles. However, their precise synthesis and structure–property relationships require further investigation. In this study, hydroxylated polybutadiene with adjustable topology and hydroxyl group density was employed as a macroinitiator to synthesize well-defined amphiphilic poly (ethylene oxide)-b-poly(ε-caprolactone-ran-δ-valerolactone) (PEO-b-P(CL-ran-VL)) copolymers via ring-opening polymerization (ROP). A series of linear, star, linear–comb, and star–comb copolymers were prepared as curcumin-loaded micellar carriers for the study. The self-assembly behavior, drug encapsulation efficiency, and in vitro release profiles of these copolymers in aqueous environments were systematically investigated. The results demonstrated that increasing the branch length of star–comb copolymers effectively reduced micelle size from 143 to 96 nm and enhanced drug encapsulation efficiency from 27.3% to 39.8%. Notably, the star–comb architecture exhibited 1.2-fold higher curcumin encapsulation efficiency than the linear counterparts. Furthermore, the optimized star–comb nanoparticles displayed sustained release kinetics (73.38% release over 15 days), outperforming conventional linear micelles. This study establishes a quantitative structure–property relationship between copolymer topology and drug delivery performance, providing a molecular design platform for programmable nanocarriers tailored to diverse therapeutic requirements of various diseases. Full article

Lithium batteries have gained significant attention due to their high energy density, specific capacity, operating voltage, slow self-discharge rate, good cycle stability, and rapid charging capabilities. However, the use of liquid electrolytes presents several safety hazards. Solid-state polymer electrolytes (SPEs) offer a promising alternative to mitigate these issues. This study focuses on the preparation of an ionically conductive electrospun membrane and its potential application as an SPE. To support a circular approach and reduce the environmental impact, the target polymeric formulation combines poly(ethylene oxide) (PEO) and lignin, sourced from paper industry waste. The formulation is optimised to ensure the dissolution of lithium salts and enhance the membrane integrity. The addition of lignin is crucial to contrast the dendrites’ growth and prevent the consequent battery breakdown. The electrospinning process is adjusted to obtain stable, homogeneous nanofibrous membranes, which are characterised using electron scanning microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The membranes’ potential as an SPE is assessed by measuring their ionic conductivity (>10⁻⁵ S cm⁻¹ above 50 °C) and anodic stability (≈4.6 V vs. Li/Li⁺), and by testing their compatibility with lithium metal by reversible cycling in a symmetric Li|Li cell at 55 °C. Full article

The use of fibers or fabrics as frameworks for loading photocatalysts is beneficial in solving the problems of photocatalytic nanomaterials, which tend to agglomerate and are difficult to recycle. In this study, Bi₂WO₆/CFb and Bi₂WO₆/Bi₂S₃/CFb photocatalytic fibers rich in oxygen vacancies were prepared using carbon fibers as the framework by the crystal seed attachment method and in situ growth method by using the self-polymerization and strong adhesion properties of dopamine. The results of SEM, TEM and XRD tests showed that Bi₂WO₆ and Bi₂WO₆/Bi₂S₃ nanosheets were uniformly and completely encapsulated on the surface of the carbon fibers. The results of XPS and EPR tests showed that Bi₂WO₆ nanosheets were rich in oxygen vacancies. The PL, transient photocurrent responses and EIS results showed that the introduction of Bi₂S₃ significantly improved the migration efficiency of the photogenerated carriers of Bi₂WO₆/Bi₂S₃/CFb, which effectively hindered the recombination of photogenerated electron–hole pairs. By conducting degradation experiments on p-nitrophenol and analyzing the bandgap structure, it was postulated that the heterojunction structure of Bi₂WO₆/Bi₂S₃/CFb in the Bi₂WO₆/Bi₂S₃ material was not Type-II but Z-scheme. As analyzed by the active species assay, the active species that played a major role in the degradation process were O₂⁻ and h⁺. The incorporation of a small amount of Bi₂S₃ resulted in enhanced photocatalytic degradation activity of Bi₂WO₆/Bi₂S₃/CFb toward tetracycline hydrochloride compared to Bi₂WO₆/CFb. The excellent photocatalytic performance of Bi₂WO₆/Bi₂S₃/CFb photocatalytic fibers can be attributed to the rapid transmission and separation performance and the high oxidation and reduction capacities of photogenerated electron–hole pairs formed by direct Z-scheme heterojunctions. Full article

A magnetic shell-structured nano-catalyst was prepared by self-polymerization of dopamine wrapped by ferric oxide as the carrier, which was loaded with palladium nanoparticles (Pd/PDA@Fe₃O₄). The presence of magnetic Fe₃O₄ made it easy for nanoscale palladium particles to recover and prevent the loss of palladium nanoparticles that is unavoidable in traditional usage and preparation procedures. The catalyst was characterized by X-ray diffraction, fourier transform infrared spectroscopy, scanning electron microscopy, thermal weight loss analysis, Raman spectroscopy, X-ray photo-electron spectroscopy, and magnetic properties analysis. The catalytic performance of the prepared catalyst was investigated taking 4-nitrophenol (10 mg/L) and rhodamine B (15 mg/L) as the target pollutants. The results showed that under the conditions of 35 °C, pH = 7 and a catalyst dosage of 3 mg, the catalytic reduction efficiency of 4-nitrophenol, rhodamine B, and the mixture of them all can reach 99%. The catalytic efficiency of Pd/PDA@Fe₃O₄ remained above 90% after being used 10 times. The shell structure of Fe₃O₄ made it possible and easy to recover and recycle the nanoscale palladium, which was a real problem in the usage of nano-catalysts. At the same time, the problem of separation and recovery of palladium nano-catalyst is solved by magnetism, which provides research ideas for the recycling and utilization of nano-materials. Full article