Hydrogels are hydrophilic, three-dimensional porous networks that absorb and retain large amounts of water, making them promising materials for environmental remediation. In this study, a novel hydrogel composite based on pectin (PEC), xanthan gum (XG), and poly(vinyl alcohol) (PVA), reinforced with graphene oxide (GO), was successfully synthesized via a sol–gel approach using combined freeze–thaw (FT) and citric acid (CA) crosslinking. The resulting composite is hereafter denoted as the FT–CA–GO hydrogel. The synthesised FT-CA–GO was subsequently investigated as an effective adsorbent for removing Basic Blue 12 (BB12) dye from water. We systematically characterised the hydrogel’s structural, morphological, and thermal properties using FTIR, XRD, BET, TGA, FESEM-EDX, and TEM analyses. ANOVA with Response Surface Methodology (RSM) based on the Box–Behnken design (BBD) was used to assess the optimum conditions for the best adsorption performance: pH 7, 30 °C, 60 min contact time, 0.07 g adsorbent dosage, and 600 mg L⁻¹ initial dye concentration. The experimentally measured equilibrium adsorption capacity reached 948.66 mg g⁻¹, while nonlinear Langmuir fitting yielded a model-estimated maximum adsorption capacity (qₘ) of 988.66 mg g⁻¹, and the removal efficiencies exceeded 97.66
Dye contamination poses serious threats to the environment and human health. Herein, polyaniline-functionalized magnetic activated carbon (PANI-mBAC) was prepared via chemical oxidative polymerization for methyl orange removal from water. Under optimal conditions (10 mg adsorbent, pH 7.0, 40 min, 250 mg/L, 308 K), the material showed excellent adsorption performance. The adsorption followed pseudo-second-order kinetics (R2 = 0.996) and Langmuir isotherm (R2 = 0.997), with a maximum capacity of 271 mg/g, indicating monolayer chemisorption on a homogeneous surface. Thermodynamic analysis revealed a spontaneous and endothermic process. FTIR analysis before and after adsorption revealed obvious interactions between PANI-mBAC and methyl orange, confirming the occurrence of adsorption. After five cycles, over 80
This study reports the design, synthesis, and evaluation of a novel negative-working near-infrared (NIR) lithographic imaging system, with emphasis on material development, interfacial assembly, and performance improvement enabled by a dual crosslinking strategy. Three key materials, namely a reactive stabilizer PGIMA, a non-aqueous polymer dispersion NAPD-PASVP, and a hydrogen-bonding donor PETAMA, were synthesized and systematically characterized, with the reference variant NAPD-PAS also prepared. Zeta-potential measurements confirmed hydrogen-bonding interactions between PETAMA/PETA and pyridine moieties on NAPD-PASVP particles. These materials were formulated into near-infrared (NIR)-sensitive coatings on anodized-aluminum substrates containing NIR dye IR830 and thermal initiator BtBPI. Upon exposure to 830 nm laser light, heat from laser excitation drove successive particle coalescence, initiator cleavage, and radical polymerization of acrylate monomers to generate crosslinked lithographic patterns. The dependence of imaging performance on the dosages of PETAMA and PETA was investigated. Notably, neat-PETAMA and PETAMA/PETA composite systems with sufficiently high PETAMA loading achieved superior imaging resolution and solvent resistance. They produced high-resolution patterns at 150 mJ/cm² and preserved structural integrity upon immersion in a 2-butanone/1-methoxy-2-propanol mixed solvent, whereas control samples exhibited varying degrees of solvent-triggered erosion. Scanning electron microscopy (SEM) was employed to characterize the morphological evolution of the NIR-sensitive coating before and after exposure, and water contact angle measurements were used to assess the corresponding changes in surface wettability.
Skin wounds represent a major entry point for microbial colonization and frequently lead to infections that may progress to systemic complications if left untreated. Although antibiotics have been employed to treat such infections, their extensive use has contributed to the growing problem of antimicrobial resistance. Consequently, natural bioactive compounds, such as metabolic extracts from endophytic bacteria and essential oils, have emerged as promising alternatives in the efforts against multidrug resistance. Here we investigated antimicrobial formulation based on endophytic bacteria isolated from Anacardium humile, a plant native to the Brazilian Cerrado, combined with essential oils and incorporated into polymeric fibers. To this end, endophytic bacteria were isolated from branches and leaves of Anacardium humile, and the two most antagonistic strains against E. coli, S. aureus, and C. albicans were taxonomically identified as B. subtilis and B. amyloliquefaciens. The optimization of bacterial metabolic extracts (ME) production from these endophytic bacteria were used to develop natural antimicrobial formulations by combining the bacterial ME with clove and limonene essential oils (EO), resulting in formulations that demonstrated antimicrobial effects against the tested pathogens. These ME-EO formulations were encapsulated within fibers of a biodegradable poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blend using the solution blow spinning technique, thereby producing antimicrobial wound dressings. The resultant fiber-based wound dressings demonstrated both inhibition halos formation and contact-based antimicrobial activity against the pathogens studied. Furthermore, the as-produced ME-EO-fibers exhibited significantly reduced cytotoxicity toward fibroblast cells compared with the non-encapsulated natural antimicrobial formulations. These results highlight the potential of combining endophytic bacterial metabolites and essential oils within polymeric fibers as a strategy for the development of bioactive wound dressings.
Polyurethane hydrogels (PUHs) have emerged as highly attractive biomaterials owing to their exceptional water uptake capacity and inherent biocompatibility. In this work, a novel diisocyanate-free route was developed for the synthesis of a highly swellable polyurethane hydrogel from poly(ethylene glycol) (PEG, -M n = 200 g mol− 1) and glycerol. PEG was oxidized to its dicarboxylic acid (PEGDAc) using alkaline KMnO₄, then converted to the diacyl azide (PEGDAz) via ethyl chloroformate activation and sodium azide. The Curtius rearrangement of PEGDAz generates a diisocyanate intermediate in-situ, which directly reacts with trifunctional glycerol to form the crosslinked urethane network, eliminating the need for isolation of toxic isocyanate. Structural characterization by FTIR spectroscopy verified each synthetic step, and 1H and 13C NMR analyses unequivocally confirmed the PEGDAz structure. FE-SEM revealed a porous, microphase-separated morphology, and EDX confirmed the presence of urethane nitrogen. Thermal analysis (TGA-DTG/DSC) showed a two-step degradation with maxima at 202 °C and 359 °C, corresponding to urethane and PEG ether cleavage, confirming stability up to 170 °C. The effective cross-link density, estimated using the Flory–Rehner equation from equilibrium swelling data, was found to be 6.77 × 10− 3 mol cm− 3, which is consistent with the high water uptake capacity (98
