Search Results (3,413)

Self-healing biomaterials have attracted significant attention due to their ability to restore structural integrity, extend material lifetime, and reduce maintenance costs without external intervention. In this study, Polyvinyl Alcohol/Graphene Oxide/Eggshell Particle (PVA/GO/ESP) composite hydrogels were synthesized via a freeze–thawing method and characterized using XRD, SEM/EDS, and FTIR analyses. The effect of ESP incorporation on the self-healing and mechanical properties of the hydrogels was systematically investigated. Tensile test results demonstrated that incorporation of 1 wt% ESP improved the tensile strength up to 0.326 MPa while maintaining high strain capacity. Healing efficiency values calculated from recovered tensile strength showed approximately 69%, 47%, and 67% recovery for PVA/GO, PVA/GO/ESP (0.5%), and PVA/GO/ESP (1%) hydrogels, respectively. The developed hydrogels demonstrated rapid self-healing behavior at room temperature without external stimuli. These findings suggest that ESP-reinforced PVA/GO hydrogels may serve as promising candidates for future biomaterial and soft tissue engineering studies. The developed hydrogels demonstrated enhanced tensile strength, rapid self-healing behavior, and promising swelling properties, indicating their potential use in soft tissue engineering and biomaterial applications. Full article

Hydrogels have garnered significant attention due to their tunable structures and broad applicability in biomedical and smart materials. However, achieving a balance between excellent mechanical performance and multifunctionality remains a major challenge. In this study, a series of multifunctional polyurethane hydrogels (PUGs) was developed by integrating dynamic disulfide bonds and pendant tertiary amine groups into poly(ethylene glycol)-based networks using a solvent-exchange method. Structural characterization confirmed the successful formation of a crosslinked porous network. The hydrogels demonstrated remarkable mechanical properties, with PUG–II exhibiting a tensile strength of 448 kPa and an elongation at break of 489%, as well as exceptional compressibility (371 kPa at 90% strain) and fatigue resistance. Meanwhile, the PUGs displayed efficient room-temperature self-healing with a healing efficiency of up to 94.5%. The reversible protonation of tertiary amine groups imparted pronounced pH-responsive swelling behavior, with the equilibrium swelling ratio of PUG–I at pH 2.0 being 5.8 times higher than that at pH 12.0. This study provides a promising strategy for developing PU-based hydrogels that combine robust mechanical performance and multifunctionality, offering potential for advanced smart material applications. Full article

The transition toward a circular economy is accelerating the development of high-performance, sustainable polymeric materials derived from renewable resources. Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) represent a versatile class of biodegradable polyesters with inherent flexibility and tunable side-chain chemistry, making them attractive candidates for advanced polymer applications. Here, we report a novel class of bio-based polyurethanes (PUs) incorporating mcl-PHAs as soft segments, marking their first application in polyurethane synthesis and shifting towards greener PU synthesis. Polyurethane networks were prepared using castor oil (CO) and mcl-PHAs as polyols, with hexamethylene diisocyanate (HMDI) as a hard segment. Material properties were systematically tuned by varying the mcl-PHA/CO ratio (100/0 to 0/100), enabling precise control over structure–property relationships. Comprehensive characterization confirmed urethane bond formation and revealed predominantly amorphous materials with tunable thermal and mechanical behavior. Increasing mcl-PHA content enhanced elasticity and influenced phase organization, underscoring its role as a flexible, bio-derived soft segment. The resulting materials exhibited competitive mechanical performance alongside adjustable swelling behavior and morphology. Importantly, in vitro biocompatibility (MRC-5 fibroblasts) and eco-toxicological evaluation (Caenorhabditis elegans) confirmed the absence of toxicity. These findings highlight the potential of mcl-PHAs as sustainable building blocks for advanced polyurethane systems. Full article

Waterlogged archaeological wood represents a unique cultural heritage but is highly susceptible to physical and chemical degradation, which complicates conservation and restoration. This study aimed to prepare artificial archaeological Cunninghamia lanceolata wood using NaOH vacuum impregnation and systematically evaluate the effects of NaOH concentration and treatment cycles as two treatment variables on wood degradation. Untreated heartwood specimens were treated with 5%, 10%, 20%, and 30% NaOH solutions for 2, 4, and 6 cycles. The NaOH treatment first induced chemical and structural deterioration, including selective degradation of hemicelluloses, changes in cellulose crystallinity, and progressive damage to the wood cell-wall structure. XRD analysis revealed a significant reduction in cellulose crystallinity from 35.96% to 10.11%, while FTIR confirmed the degradation of hemicelluloses and the relative enrichment of lignin-related structures. SEM observations further showed severe cell-wall erosion, lumen deformation, and local collapse, indicating that alkali treatment effectively reproduced typical microstructural features of degraded waterlogged wood. These chemical and microstructural changes subsequently led to marked changes in physical and mechanical properties. Mass loss increased with NaOH concentration and cycle number, while basic density decreased and maximum water content increased, indicating enhanced deterioration and water-holding capacity. Treated specimens also exhibited increased swelling and shrinkage rates and a substantial reduction in longitudinal compressive strength, with the most pronounced deterioration occurring under higher NaOH concentrations and repeated cycles. The study demonstrates that NaOH treatment can reproducibly simulate the physical, chemical, and microstructural characteristics of waterlogged archaeological wood, providing a reliable experimental model for studying wood degradation mechanisms and supporting conservation strategies. Full article

Background/Objectives: Oral candidiasis is an infection of the oral cavity caused by Candida albicans. Mucoadhesive buccal films could adhere to the buccal mucosa for prolonged periods, improving the therapeutic outcomes of patients with oral candidiasis. This study aimed to develop and evaluate the properties of fluconazole containing sodium alginate/methylcellulose-based buccal films for potential treatment of oral candidiasis. Methods: Drug-polymer compatibility was investigated using FT-IR spectrophotometry. Three optimised fluconazole films (F1 to F3) containing 1–1.6% sodium alginate and methylcellulose (1.6%) were formulated using the solvent-casting method. Their physicomechanical properties were characterised using standard protocols. Drug content and in vitro drug release profiles were evaluated using UV-visible spectroscopy; in vitro/ex vivo mucoadhesion studies were conducted using the shaking water bath technique, and their antifungal activity against Candida albicans was evaluated using the agar ditch method. Results: FT-IR data analysis revealed that sodium alginate, methylcellulose and fluconazole were compatible in the films. The films were off-white, smooth, peelable, thin, with satisfactory pH values, folding endurance, drug content, excellent zones of inhibition against Candida albicans (40 mm), controlled drug release profile (3.6–4.1 mg/cm² after 6 h), and they displayed Korsmeyer–Peppas drug release kinetics. Film F3 containing 1.6% sodium alginate and 1.6% of methylcellulose exhibited superior swelling index (70 ± 1%), tensile strength (0.68 ± 0.04 MPa) and in vitro/ex vivo mucoadhesion time (5.5 ± 0.3 h; 2.3 ± 0.3 h) relative to other studied films. Conclusions: The sodium alginate content of the films influenced their tensile and mucoadhesive properties. Film F3 was the most promising formulation for potential treatment of oral candidiasis. Full article

Multifunctional dressings capable of maintaining a moist environment, supporting tissue regeneration, and delivering bioactive compounds are increasingly being explored as promising strategies for burn wound management. In this study, alginate-based emulgel patches incorporating hydrophilic and lipophilic plant extracts were developed by extrusion-based 3D printing as potential topical systems for burn wound applications. The formulation included sodium alginate, hyaluronic acid, and hydroglyceric extracts of Calendula officinalis, Matricaria chamomilla, and Plantago major, as well as oily extracts of Hippophae rhamnoides and Hypericum perforatum. The emulgel was evaluated for pH, rheological behaviour, spreadability, physical stability, apparent hydrodynamic size distribution, zeta potential, total polyphenol content, and antioxidant activity. Following Ca²⁺-induced crosslinking, uniform and flexible 3D-printed patches were obtained and further characterised for pharmacotechnical, physicochemical, structural, functional, and biological properties. The emulgel exhibited suitable characteristics for extrusion-based printing, while the resulting patches showed good dimensional uniformity, flexibility, swelling capacity, water vapour transmission, and surface pH compatible with topical application. FTIR, DLS, SEM, and SEM–EDX analyses supported the formation of a Ca²⁺-crosslinked alginate network and confirmed the presence of structurally heterogeneous domains with homogeneous calcium distribution. The patches retained plant-derived bioactive compounds, with a total polyphenol content of 0.2878 ± 0.016 mg GAE/g hydrated patch, and showed improved antioxidant activity compared with the corresponding emulgel. In vitro release studies indicated the time-dependent diffusion of polyphenols over 24 h, with cumulative release reaching 64.42%. The patches also exhibited a water vapour transmission rate of 1270 ± 93 g/m²/24 h, indicating adequate moisture regulation. HaCaT cell viability remained above 90% at lower tested concentrations, demonstrating a favourable biocompatibility profile. Overall, the developed 3D-printed alginate emulgel patches represent promising multifunctional systems for potential burn wound management and warrant further preclinical investigation. Full article

Potato starch (Solanum spp.) undergoes structural and functional modifications during traditional Andean chuño production; however, the integrated effects of processing history, cultivar-associated characteristics, and field-based environmental conditions remain insufficiently characterised. This study investigated the effects of chuño processing on the compositional, pasting, morphological, molecular, and crystalline properties of starches isolated from three potato cultivars (Condor Imilla, Luk’i Turno, and Dutch Désirée). Native and chuño starches were characterised by amylose quantification, viscoamylography, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), together with severe thermal treatment to evaluate structural stability. Chuño processing was associated with a reduction in amylose content across all cultivars (6.9–23.4%) and an increase in gelatinisation onset temperature of approximately 21.5% (from ~65 °C to ~79 °C). Peak viscosity decreased substantially after processing (457.5–1110 BU to 194.5–442.5 BU), while breakdown values remained close to zero, indicating increased resistance to viscosity loss during heating. SEM analysis revealed changes in granule morphology and size distribution associated with chuño processing and subsequent thermal treatment, with more pronounced reductions in granule size observed in Condor Imilla and Luk’i Turno than in Dutch Désirée. FT-IR analysis demonstrated modifications in short-range molecular organisation without the appearance of new functional groups, indicating structural reorganisation rather than chemical transformation. XRD analysis confirmed that all starches retained the native B-type crystalline polymorph after chuño processing, although reductions in diffraction intensity and peak definition indicated decreased long-range structural order. Severe thermal treatment eliminated detectable crystalline order in all samples, producing predominantly amorphous diffraction profiles. Overall, chuño processing was associated with reduced swelling capacity, lower paste viscosity, enhanced thermal stability, and multiscale structural reorganisation while preserving the fundamental B-type polymorph. Given that the plant material originated from distinct agroecological environments and that traditional chuño production involved a variable number of processing cycles, the observed differences should be interpreted as integrated responses of starch systems to processing history and material characteristics rather than strictly genotype-driven effects. These findings highlight the potential of chuño as a naturally modified starch system with distinctive technological properties. Full article

Objectives: To address the critical limitations of current formulations that fail to simultaneously resolve indomethacin’s poor water solubility, susceptibility to gastric acid hydrolysis, and difficulty in balancing rapid onset with long-term sustained release, this study prepared solid dispersions via anti-solvent freeze-drying to improve drug dissolution, constructed oral buccoadhesive bilayer controlled-release tablets using direct powder compression, and elucidated the intrinsic relationships among polymer gel properties, swelling-erosion behavior, tablet integrity maintenance, and drug release mechanisms. Methods: Solid dispersions (SDs) were prepared by anti-solvent freeze-drying. Bilayer tablets (25 mg IND/tablet, 12.5 mg/layer) were fabricated via direct powder compression after optimizing disintegrants and polymer matrices. In vitro dissolution, surface pH, adhesion time, and adhesion strength were evaluated. Results: SDs enhanced dissolution by at least 30-fold in water and 2.4-fold at pH 6.8 within 2 h versus pure drug. Optimized bilayer tablets achieved 45% drug release at 20 min and 80% sustained release over 8 h, with surface pH of 6.8 ± 0.1, adhesion time of 8.3 ± 0.1 h, and adhesion strength of 57 ± 0.13 g. Conclusions: The physicochemical properties of polymeric excipients are critical for balancing drug release and mucoadhesion in buccal tablets. To achieve ideal controlled-release effects, in addition to focusing on the swelling and erosion characteristics of matrix-based tablets, the ability to maintain tablet integrity during dynamic dissolution must be further investigated, which is an essential factor for ensuring precisely modulated drug release. Meanwhile, when employing solid dispersions as solubilizing intermediates to prepare controlled-release formulations, the gelling properties of polymers in each formulation component should be fully considered to avoid incomplete disintegration and insufficient release at the initial dissolution stage. Full article

Conductive hydrogel strain sensors using poly(3,4-ethylenedioxythiophene) (PEDOT) as fillers are rapidly advancing and are emerging as candidates for monitoring devices such as wearable electronic skin. However, due to limitations such as low elongation and high hysteresis, it is difficult to fully leverage its promising sensor properties in practical applications. In this study, we synthesized flake-like PEDOT particles (FP particles) and used Polyacrylamide (PAM) as the hydrogel matrix to fabricate a conductive hydrogel strain sensor. These particles were obtained by grinding PEDOT particles prepared via a template-free method. After swelling with ethylene glycol (EG) and assembly with polyvinyl alcohol (PVA), the FP particles become porous and contain many hydroxyl groups. This design enables the adsorption of acrylamide (AM) monomers within FP particles, facilitating the in situ polymerization of PAM onto the PEDOT/PVA chains, thereby yielding a dual-network structure with strong entanglements. This gives the sensor high elongation and very low hysteresis. In addition, it offers favorable sensor performance, including high sensitivity, high repeatability, and reliability. This strain sensor can be used in wearable electronic skin applications for facial monitoring and motion detection. Full article

The aim of this study was to evaluate the effect of matrix type and dose of polyphenolic core from rose petals on the physicochemical and functional properties of microcapsules. Microcapsules were obtained by ionotropic gelation using four carrier systems: sodium alginate (SA), sodium alginate with added starch (SA + S), protein isolate (SA + P), and vegetable gum (SA + G). Polyphenolic compounds isolated from rose petals (E) were used as the core at six concentrations (0.25, 0.5, 1.0, 1.5, 2.0, and 2.5%). Differences between microcapsules were assessed based on physicochemical properties, polyphenol and anthocyanin content, antioxidant activity, swelling index, and biocompatibility. The results showed that both the extract dose and the matrix system significantly affected the analyzed parameters. The highest encapsulation efficiency was demonstrated for the lowest dose (0.25%), regardless of the matrix used. Total polyphenol and anthocyanin content significantly increased for all microcapsule versions with increasing extract dose, with the highest concentrations obtained for the SA + G system. These results strongly correlated with antioxidant activity and biocompatibility with human colonocyte membranes. In turn, the swelling index decreased with extract dose, showing the highest values in small intestinal fluid and the lowest in gastric fluid. These findings may have significant implications for the design of functional carriers for use in food and dietary supplement production. Full article

A thermoreversible dynamic covalent network was constructed in recycled polyethylene terephthalate (RPET) via Diels–Alder (DA) chemistry to enhance mechanical performance, reprocessability, and self-healing. Furan-functionalized RPET (RPET-3F) was first prepared from maleated RPET (RPET-MA), followed by crosslinking with bismaleimide (BMI) at different feed ratios. FTIR spectra confirmed the successful grafting of furan groups and the formation of DA adducts. With increasing BMI content, the gel fraction and crosslink density increased substantially, whereas the swelling ratio decreased, indicating the progressive development of a three-dimensional network. RPET-3F-2B showed the highest network integrity among all samples. DSC analysis revealed a distinct retro-DA dissociation peak at 143 °C and a recrosslinking peak near 124 °C, confirming the thermal reversibility of the DA network. Owing to the optimized network structure, RPET-3F-2B exhibited the best mechanical properties and excellent reprocessability, retaining stable performance after three hot-pressing cycles. After repeated reprocessing, its tensile strength remained 74% higher than that of RPET-MA, while the elongation at break was still improved by about 10%. Moreover, the sample showed efficient thermally induced self-healing at 150 °C, with surface cracks nearly disappearing after 4 h. These results demonstrate that DA chemistry offers a promising route to the high-value reutilization of RPET into recyclable, multifunctional polymer materials. Full article

Bauhinia forficata leaves were subjected to ultrasonic pretreatment and subsequently dried using a refractance window (RW) and tray drying (TD). The physical, chemical, and biological properties of the dried leaves were evaluated under both drying methods, with and without ultrasound. RW combined with ultrasound (RW-US) resulted in the shortest drying time (90 min) and the lowest values of water activity (0.21), color difference (ΔE = 0.61), and maximum shear force (14.72 N), indicating improved drying efficiency and texture preservation. In addition, the RW-US samples exhibited the highest water solubility capacity (13.75%), water absorption capacity (5.56 g water/g dry matter), and swelling power (9.95%). With respect to structural changes, thickness showed the greatest percentage reduction during drying. The RW-US treatment also preserved bioactive compounds more effectively, yielding the highest total polyphenol content (61.96 mg GAE/g extract), flavonoid content (308.44 mg QE/g extract), antioxidant activity (60.50% by DPPH• and 70.15% by ABTS•+), and chlorophyll content (2.65 mg/g), the values of which were closest to those of fresh leaves. None of the extracts showed cytotoxic effects, with respect to hypoglycemic activity, the best treatments were RW, RW-US, and TD, which resulted in glucose reductions of 51.64%, 41.95% and 39.70%, respectively. Overall, RW-US drying preserved most of the physical, chemical, and biological properties, resulting in the production of a potential functional ingredient for foods. Full article

Template removal represents a critical yet often underexplored step in the fabrication of electropolymerized molecularly imprinted polymers (e-MIPs), directly influencing cavity integrity, selectivity, and sensor performance. In this review, we provide a comprehensive analysis of the most commonly employed template removal strategies, including immersion-based methods and electrochemical cleaning, with a particular focus on systems based on polypyrrole (PPy) and poly(o-phenylenediamine) (PoPD). We examine how template removal conditions, such as solvent composition, pH, and applied potential, affect polymer structure, doping state, swelling behavior, and electrochemical properties. Special attention is given to mechanistic aspects such as protonation/deprotonation, overoxidation, and polymer–template interactions, which govern both remotion efficiency and potential degradation pathways. By comparing PPy and PoPD systems, we highlight how intrinsic polymer properties dictate the suitability of specific removal strategies. Additionally, we discuss emerging approaches, including multi-step template removal protocols and the incorporation of conductive nanomaterials to mitigate performance loss. This work aims to provide a mechanistic perspective on how template removal conditions affect polymer structure, electrochemical properties, and the overall performance of e-MIP-based sensors. Full article

Thermal annealing improves the mechanical, structural, and electrical properties of polymer thin films, promoting processes like residual solvents and stress removal, as well as the crystallization and densification of the gel layer. The effects are strongly dependent on the annealing temperature, where optimal temperatures enhance film performance, while excessive thermal exposure may induce negative outcomes like amorphous structural transitions, increased roughness, and defect formation. In this work, thin films of two humidity-sensitive poly(vinyl alcohol) (PVA)-based copolymers with grafted poly(N,N-dimethylacrylamide) (PDMA) chains were investigated. The polymers differ in grafting density and chain length, enabling the assessment of macromolecular architecture’s effects. Spin-coated films with 150–200 nm thickness were annealed at three temperatures: 60 °C, 120 °C, and 180 °C. By using UV-VIS-NIR spectroscopy and the quartz crystal microbalance method, a comprehensive characterization of temperature- and humidity-induced changes in swelling, hysteresis, sensitivity, detection resolution, and water uptake is performed, elucidating the role of the macromolecular architecture on the post-deposition annealing modification of gel film properties and its humidity response. High-performance humidity sensing with a resolution of 0.8% RH is achieved through the optimization of the interplay between the macromolecular architecture and annealing temperature. In addition, the study highlights and explores the potential of these films for optical color-based moisture detection. Full article

The incorporation of ground tire rubber (GTR) into elastomeric compounds offers a sustainable route for recycling end-of-life tires; however, its effect on the structure–property relationships governing mechanical and dielectric performance remains insufficiently understood. In this study, NR/SBR composites containing 0–50 phr of devulcanized GTR were prepared and characterized through Fourier-transform infrared spectroscopy (FTIR), swelling analysis, thermogravimetric analysis (TGA), mechanical testing, and broadband dielectric spectroscopy. FTIR and swelling results revealed enhanced matrix–GTR interaction at intermediate GTR loadings (10–20 phr), evidenced by an increased intensity of sulfur-related bands and reduced swelling degree, indicating partial chemical integration of the recycled phase into the elastomer network. Mechanical testing showed that increasing GTR content increased stiffness at high loadings, while tensile strength, elongation at break, and toughness progressively decreased due to interfacial debonding mechanisms. TGA demonstrated that the main degradation temperature of the NR/SBR matrix remained essentially unchanged (418–425 °C) across all formulations, confirming preservation of thermal stability despite increasing structural heterogeneity. Dielectric spectroscopy (10⁻²–3 × 10⁶ Hz, 40–120 °C) revealed pronounced Maxwell–Wagner–Sillars interfacial polarization and thermally activated charge transport, with conductivity increasing with GTR content without evidence of electrical percolation, even at 50 phr. The results demonstrate that the performance of NR/SBR/GTR/SiO₂ composites is primarily controlled by the interfacial structure generated by the recycled phase. Intermediate GTR contents (10–20 phr) provide the most effective matrix–GTR interaction, while higher loadings mainly affect mechanical integrity and dielectric response through increased structural heterogeneity. These findings provide practical guidelines for designing sustainable elastomeric compounds with high recycled content while maintaining thermal stability and controlled electrical insulation properties. Full article