Search Results (79)

To understand glycan–protein interactions at biological interfaces, designing surfaces modified with structurally controlled glycans is highly important. In particular, naturally occurring glycosaminoglycans (GAGs) possess periodic sugar arrangements that play important roles in protein recognition, highlighting the need for the development of periodic glycopolymer model systems that can serve as GAG mimics for quantitative interaction analysis. In this study, sequence-controlled periodic glycopolymers were synthesized by reversible addition–fragmentation chain-transfer (RAFT) polymerization and immobilized onto gold surfaces to construct glycan-modified interfaces. The synthesized material was a terminally functionalized periodic glycopolymer with the most basic structure, consisting of alternating maltose-containing vinyl ether (MalVE) units and ethyl maleimide (EtMI) units, with a trithiocarbonate group at the ω-terminal. This trithiocarbonate group was converted to a thiol group for immobilization through Au–S bond formation. Structural characterization by ¹H NMR spectroscopy, size exclusion chromatography (SEC), MALDI-TOF mass spectrometry, and UV–vis spectroscopy confirmed the structure as designed. Quartz crystal microbalance (QCM) measurements verified the stable immobilization of thiol-terminated periodic glycopolymers on the gold surface, and allowed for estimation of graft density and quantitative analysis of glycan-protein interactions at the modified interface. The periodic glycopolymer-modified surfaces exhibited selective binding behavior toward concanavalin A (ConA) compared to bovine serum albumin (BSA), with apparent binding constants on the order of 10⁶–10⁷ L mol⁻¹. This enhanced binding behavior indicated that specific and multivalent interactions with proteins also occurred at periodic pendant maltose residues along the main chain. These results demonstrate that the gold surface modified with end-functional periodic glycopolymers synthesized by RAFT polymerization provides a versatile platform for quantitative analysis of glycan-protein interactions and suggests potential applications for periodic glycopolymers as functional materials. Full article

The temperature-sensitive plugging agent (HAAN) was synthesized via free-radical graft polymerization using hydroxypropyl methyl cellulose (HPMC), acrylamide (AM), 4-acryloylmorpholine (ACMO) and N-vinyl-2-pyrrolidone (NVP) as the main monomers. HAAN demonstrates potential for addressing the frequent lost circulation problems encountered during the drilling of complex formations. The target product was characterized by FTIR and ¹H NMR. Its phase transition behavior was verified via temperature-dependent UV-visible transmittance measurements and high-temperature rheological tests. The experimental results show that the plugging agent possesses good temperature and salt tolerance, and its rheological properties can be enhanced by incorporation into drilling fluid. It demonstrates effective plugging performance both at room temperature and under high-temperature conditions, thereby contributing to improved wellbore stability. It provides a new idea for green multifunctional application of cellulose in water-based drilling fluid. Full article

Polypropylene (PP) nonwoven is widely used in biomedical textiles because of its lightweight and mechanical durability; however, its inherent hydrophobicity and chemical inertness limit further surface functionalization. In this study, a plasma-assisted UV grafting strategy was developed to fabricate thermo-responsive and antibacterial hydrogel coatings on PP nonwoven. Atmospheric-pressure plasma jet (APPJ) treatment was first employed to activate the PP nonwoven surface, followed by UV-induced graft polymerization of chitosan and N-isopropylacrylamide (NIPAAm), forming a chitosan-co-PNIPAAm hydrogel immobilized on the nonwoven substrate. Surface characterization using water contact angle measurement, Fourier transform infrared spectroscopy, and scanning electron microscopy confirmed effective plasma activation and successful hydrogel grafting. APPJ treatment significantly enhanced surface wettability, whereas subsequent UV grafting formed a continuous hydrogel on the PP nonwoven surface. The modified nonwoven exhibited distinct thermo-responsive swelling behavior in aqueous and simulated physiological environments, associated with the temperature-sensitive characteristics of the PNIPAAm component. In addition, the incorporation of chitosan imparted pronounced antibacterial activity against Escherichia coli, with inhibition zone diameters ranging from 14 to 16.5 mm, indicating high antibacterial sensitivity. Preliminary cytocompatibility evaluation further demonstrated favorable cell viability on the modified surfaces. This study demonstrates a scalable and low-temperature surface engineering approach for integrating stimuli-responsive and antibacterial hydrogel functionality into nonwoven polymer substrates, offering potential for advanced biomedical textile applications. Full article

Polyhedral oligomeric silsesquioxanes (POSS) harness their molecularly precise organic–inorganic hybrid cage architecture to deliver hardness, scratch resistance, and programmable functionality for next-generation transparent coatings. Tailoring of solubility, thermal stability, mechanical robustness, electronic characteristics, and interfacial properties is achieved through strategic peripheral modifications enabled by versatile synthetic methodologies—spanning metal catalysis, metal-free routes, and selective bond activation. Advanced integration techniques, including covalent grafting, chemical crosslinking, UV–thermal dual curing, and in situ polymerization, ensure uniform dispersion while optimizing coating–substrate adhesion and network integrity. The resultant coatings exhibit exceptional optical transparency, mechanical durability, tunable electrical performance, thermal endurance, and engineered surface hydrophobicity. These synergistic attributes underpin transformative applications across critical domains: atomic-oxygen-resistant spacecraft shielding, UV-managing agricultural films, flame-retardant architectural claddings, mechanically adaptive foldable displays, and efficiency-enhanced energy devices. Future progress will prioritize sustainable synthesis pathways, emergent asymmetric cage architectures, and multifunctional designs targeting extreme-environment resilience, thereby expanding the frontier of high-performance transparent protective technologies. Full article

Hydrogels of acrylamide (AM)–acrylic acid (AA) and nanocomposite hydrogels of AM–AA and carbon nanotubes (CNTs) functionalized with acyl chloride groups (CNTs_OxCl) were synthesized and characterized, and their ability to release folic acid was analyzed. Both hydrogel types were synthesized via redox polymerization. CNTs were prepared via chemical vapor deposition. The prepared samples were analyzed via transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, differential scanning calorimetry, and field-emission scanning electron microscopy. Their swelling ability and their mechanical properties (compression tests) were determined at room temperature ~298.15 K, whereas their ability to release folic acid was studied using UV–VIS spectroscopy. The equilibrium swelling of the AM–AA hydrogels was greater than that of the AM–AA/CNTs_OxCl nanocomposite hydrogels prepared at the same monomeric relation (wt%), whereas the Young moduli of these nanocomposite hydrogels were higher than that of AM–AA hydrogels. For the AM–AA/CNTs_OxCl nanocomposite hydrogels, polymer chains containing AM and AA units were grafted to CNTs_OxCl. The glass–transition temperatures of AM–AA nanocomposite hydrogels were higher than that of AM–AA hydrogels. Folic acid release from the AM–AA hydrogels and AM–AA/CNTs_OxCl nanocomposite hydrogels was successfully adjusted using the Weibull model. Full article

To develop membranes capable of efficient and switchable emulsion separation under variable pH conditions, pH-responsive surfaces were engineered on poly(ethylene terephthalate) track-etched membranes (PET TeMs) via a two-step UV-initiated RAFT graft polymerization process. Initially, polystyrene (PS) was grafted to render the surface hydrophobic, followed by the grafting of poly(methacrylic acid) (PMAA) to introduce pH-responsive carboxyl groups. Optimized conditions (117 mM MAA, RAFT:initiator 1:10, 60 min UV exposure at 10 cm) resulted in PET TeMs-g-PS-g-PMAA surfaces exhibiting tunable wettability, with contact angles shifting from 90° at pH 2 to 65° at pH 9. Successful grafting was confirmed by FTIR, AFM, SEM, TGA, and TB dye sorption. The membranes showed high degree of rejection (up to 98%) for both direct and reverse emulsions. In direct emulsions, stable flux values (70 ± 2.8 to 60 ± 2.9 L m⁻² h⁻¹ for cetane-in-water and 195 ± 8.2 to 120 ± 6.9 L m⁻² h⁻¹ for o-xylene-in-water) were maintained over five cycles at 900 mbar, indicating excellent antifouling performance. Reverse emulsions initially exhibited higher flux, but stronger fouling; however, flux recovery reached 91% after cleaning. These findings demonstrate the potential of PET TeMs-g-PS-g-PMAA as switchable, pH-responsive membranes for robust emulsion separation. Full article

The development of sustainable and functional nanocomposites has attracted considerable attention in recent years due to their broad spectrum of potential applications, including wood preservation. Also, a global goal is to reuse the large volumes of waste for environmental issues. In this context, the aim of the study was to obtain soda lignin particles, to graft ZnO nanoparticles onto their surface and to apply these hybrids, embedded into a biodegradable polymer matrix, as protection/preservation coating for oak wood. The organic–inorganic hybrids were characterized in terms of compositional, structural, thermal, and morphological properties that confirm the efficacy of soda lignin extraction and ZnO grafting by physical adsorption onto the decorating support and by weak interactions and coordination bonding between the components. The developed solution based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and lignin-ZnO was applied to oak wood specimens by brushing, and the improvement in hydrophobicity (evaluated by water absorption that decreased by 48.8% more than wood, humidity tests where the treated sample had a humidity of 4.734% in comparison with 34.911% for control, and contact angle of 97.8° vs. 80.5° for untreated wood) and UV and fungal attack protection, while maintaining the color and aspect of specimens, was sustained. L.ZnO are well dispersed into the polymer matrix, ensuring a smooth and less porous wood surface. According to the results, the obtained wood coating using both a biodegradable polymeric matrix and a waste-based preservative can be applied for protection against weathering degradation factors, with limited water uptake and swelling of the wood, UV shielding, reduced wood discoloration and photo-degradation, effective protection against fungi, and esthetic quality. Full article

It is widely recognized that fine surface structures found in nature contribute to surface functionality, and studies on the design of functional materials based on biomimetics have been actively conducted. In this study, polymer thin films with hierarchically ordered surface structure were prepared by combining both nanoimprinting using anodically oxidized porous alumina (AAO) as a template and surface-initiated atom transfer radical polymerization (SI-ATRP). To prepare such polymer films, we designed a new copolymer (poly{[2-(4-methyl-2-oxo-2H-chromen-7-yloxy)ethyl methacrylate]-co-[2-(2-bromo-2-methylpropionyloxy)ethyl methacrylate]}; poly(MCMA-co-HEMABr)) with coumarin moieties and α-haloester moieties in the pendants. The MCMA repeating units function to fix the pillar structure by photodimerization, and the HEMABr ones act as the polymerization initiation sites for SI-ATRP on the pillar surfaces. Surface structures consisting of vertically oriented multiple pillars were fabricated on the spin-coated poly(MCMA-co-HEMABr) thin films by nanoimprinting using an AAO template. Then, the coumarin moieties inside each pillar were crosslinked by UV light irradiation to fix the pillar structure. SEM observation confirmed that the internally crosslinked pillar structures were maintained even when immersed in organic solvents such as 1,2-dichloroethane and anisole, which are employed as solvents under SI-ATRP conditions. Finally, poly(2,2,2-trifluoroethyl methacrylate) and poly(N-isopropylacrylamide) chains were grafted onto the thin film by SI-ATRP, respectively, to prepare the hierarchically ordered surface structure. Furthermore, in this study, the surface properties as well as the thermoresponsive hydrophilic/hydrophobic switching of the obtained polymer films were investigated. The surface morphology and chemistry of the films with and without pillar structures were compared, especially the interfacial properties expressed as wettability. Grafting poly(TFEMA) increased the static contact angle for both flat and pillar films, and the con-tact angle of the pillar film surface increased from 104° for the flat film sample to 112°, suggesting the contribution of the pillar structure. Meanwhile, the pillar film surface grafted with poly(NIPAM) brought about a significant change in wettability when changing the temperature between 22 °C and 38 °C. 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

In recent years, the disposal of agricultural lignocellulosic residues has been accompanied by problems such as resource waste and environmental pollution. Therefore, the development of valorization technologies has emerged as a strategic priority in sustainable materials science. This study pioneered the use of corncob cellulose as the substrate (a representative agricultural lignocellulosic residue) and transformed it into ionized cellulose by grafting methacryloxyethyl trimethyl ammonium chloride (DMC) via atom transfer radical polymerization (ATRP) and UV-initiated polymerization. Characterizations demonstrated exceptional properties: robust mechanical strength (1.28 MPa tensile strength with 573% elongation); outstanding thermal stability (stable to 278 °C); cryogenic tolerance (retaining flexibility at −25 °C); and universal adhesion capability (4.23 MPa to glass substrates, with adequate interfacial bonding across diverse surfaces). Meanwhile, the ionogel exhibited exceptional sensing sensitivity (gauge factor, GF = 1.23–2.08), demonstrating versatile application potential in wearable electronics. It achieved the precise detection of subtle strains (1–5% strain range) and the high-fidelity acquisition of electrocardiogram (ECG) signals. This study broadens the design paradigm of agricultural lignocellulosic residue-based functional materials. It also provides a novel technical pathway to develop eco-friendly intelligent sensors. Full article

Industrial waste management is a growing concern, and the valorization of by-products through circular economy approaches represents a sustainable solution. In this context, dextran–grape conjugates (PLG–GRAPE) were obtained via a grafting reaction of grape pomace extract and dextran under aqueous conditions. To compare the properties of the polymeric graft with those of the free extract, total polyphenol content was assessed using the Folin–Ciocalteu assay, along with stability and diffusion studies. In addition, in vitro safety evaluations, including Neutral Red Uptake, h-CLAT, and skin irritation tests were performed to assess the biocompatibility. To evaluate the antioxidant, anti-inflammatory, and anti-aging properties of PLG–GRAPE, in vitro efficacy assays were performed on keratinocyte and fibroblast cell lines and full-thickness reconstructed human tissues exposed to damaging agents, such as UV radiation and pollutants. The results showed that the technology preserved the phenolic and antioxidant activity of the extract, while improving diffusion and stability properties. As demonstrated by the results of the in vitro studies, a favorable biocompatibility profile was observed, in addition to a significant capacity to reduce oxidative stress and inflammation in aged cells, thus, attenuating cellular aging and senescence. In conclusion, the study suggests that PLG–GRAPE has potential as a bioactive ingredient for cosmetic and dermatological applications, offering a sustainable and effective approach to utilizing industrial waste products. Full article

Surface modification of various polymer foils was achieved by UV activation and chemical grafting with cysteamine to improve surface properties and antimicrobial efficacy. UVC activation at 254 nm led to changes in surface wettability and charge density, which allowed the introduction of amino and thiol functional groups by cysteamine grafting. X-ray photoelectron spectroscopy (XPS) confirmed increased nitrogen and sulfur content on the modified surfaces. SEM analysis revealed that UV activation and cysteamine grafting resulted in distinct surface roughness and texturing, which are expected to enhance microbial interactions. Antimicrobial tests showed increased resistance to algal growth (inhibition test) and bacterial colonization (drop plate method), with significant improvement observed for polyethylene terephthalate (PET) and polyetheretherketone (PEEK) foils. The important factors influencing the efficacy included UV exposure time and cysteamine concentration, with longer exposure and higher concentrations leading to bacterial reduction of up to 45.7% for Escherichia coli and 55.6% for Staphylococcus epidermidis. These findings highlight the potential of combining UV activation and cysteamine grafting as an effective method for developing polymeric materials with enhanced antimicrobial function, offering applications in industries such as healthcare and packaging. Full article

The problem of antibiotic abuse and drug resistance is becoming increasingly serious. In recent years, polydopamine (PDA) nanoparticles have been recognized as a potential antimicrobial material for photothermal therapy (PTT) due to their excellent photothermal conversion efficiency and unique antimicrobial ability. PDA is capable of rapidly converting light energy into heat energy under near-infrared (NIR) light irradiation to kill bacteria efficiently. In order to solve the problem of PDA’s tendency to aggregate and precipitate, this study improved its stability by grafting hyaluronic acid (HA) onto the surface of PDA. Using dopamine and hyaluronic acid as raw materials, hyaluronic acid (HA) was grafted onto polydopamine (PDA) nanoparticles via self-polymerization and Michael addition reactions under alkaline conditions to obtain PDA-HA-modified nanoparticles. We confirmed the successful grafting of hyaluronic acid via scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR), nuclear magnetic hydrogen spectroscopy (¹H NMR), ultraviolet–visible spectroscopy (UV–vis), Raman spectroscopy (Raman), and dynamic light scattering (DLS) methods. Scanning electron microscopy (SEM) was used to observe the surface morphology and nanostructure of the grafted materials, providing information on the morphology and size distribution of the materials. Near-infrared performance experiments showed that the temperature of the PDA-HA solution increased rapidly under near-infrared light irradiation, demonstrating an excellent photothermal conversion performance. Antimicrobial properties were assessed via the colony counting method, and typical Gram-positive bacteria S. aureus and Gram-negative bacteria E. coli were selected as model strains. The experimental groups were tested under dark conditions and near-infrared (NIR) light irradiation. PDA/HA showed significant photothermal properties under NIR light irradiation, resulting in a rapid increase in the surrounding temperature to a level sufficient to kill bacteria. Under NIR light irradiation, PDA/HA exhibited 100% antimicrobial efficacy against both S. aureus and E. coli, while antimicrobial efficacy was limited under dark conditions. This indicates that the antibacterial activity of PDA/HA is highly dependent on NIR light activation. Full article

The present work focuses on the synthesis and characterization of biobased lignin-poly(lactic) acid (PLA) composites. Organosolv lignin, extracted from beechwood, was used as a filler at 0.5, 1.0, and 2.5 wt% loadings, with ultrasonication reducing the lignin particle size to ~700 nm. The PLA–lignin composites were prepared via in situ ring-opening polymerization (ROP) of L-lactide in the presence of lignin. This method ensured uniform lignin dispersion in the PLA matrix due to grafting of PLA chains onto lignin particles, preventing aggregation. Strong polymer–filler interactions were confirmed through spectroscopic analysis (FTIR and XPS) and their effects on static and dynamic glass transitions (DSC). These interactions enhanced mechanical properties, including a two-fold increase in tensile strength and elongation at 1 wt% lignin. Crystallization was suppressed due to shorter PLA chains, and a 15% drop in dynamical fragility was observed via Broadband Dielectric Spectroscopy (BDS). Antioxidant activity improved significantly, with PLA–2.5% ultrasonicated organosolv lignin reducing DPPH• content to 7% after 8 h, while UV-blocking capability increased with lignin content. Full article

Hydrogels are widely used in the field of adhesive materials. However, hydrogel adhesion has previously required the covalent graft of supramolecular groups on polymeric chains. In contrast to that, here, a hydrogel adhesion induced by covalent polymer entanglement between two hydrogel networks was reported. Hydrogels G1 and G2 contain the monomers M1, with diazonium groups, and M2, with sulfonate groups, respectively. When the two hydrogels come into contact, the monomers diffuse into each other’s networks and assemble into supramolecular polymers (SPs) based on electrostatic interactions, threading the two hydrogel networks. Subsequently, SPs convert into covalent polymers (CPs) under UV light stimulation due to the reaction between the diazonium groups and sulfonate groups, leading to the entanglement of the two hydrogel networks and the production of an adhesive effect. This finding provides a novel strategy for hydrogel adhesion. Full article