Search Results (328)

The emergence of a novel crumb rubber (CR)/SBS-polymerized pellet has simplified the complex preparation process of composite-modified asphalt. However, the effectiveness of CR/SBS-polymerized pellets in improving asphalt performance has not been confirmed. This study mainly investigated the performance and reinforcement mechanism of polymerized pellet-modified asphalt. First, polymerized pellet-modified asphalt samples with different contents (10%, 20%, 30% and 40% of the asphalt mass) were prepared. Then, the physical properties, rheological behavior, thermal stability, and aging resistance of the pellet-modified asphalt samples were systematically evaluated, using both base asphalt and a commercially available styrene–butadiene–styrene triblock copolymer (SBS)-modified asphalt as control groups for comparison. Finally, the modification mechanism was explored through Fourier transform infrared spectroscopy (FTIR) and fluorescence microscopy (FM). The findings demonstrated that the incorporation of polymerized pellets could effectively decrease the penetration, elevate the softening point, and enhance the viscosity of asphalt. In addition, the high- and low-temperature performance, as well as the aging resistance of the modified asphalt, were significantly improved. These enhancing effects became more pronounced with increasing modifier content. The performance of SBS-modified asphalt is between 20% pellets MA and 30% pellets MA. The pyrolysis temperature range of all asphalt samples is 220 °C~500 °C, and infrared spectroscopy indicated that CR/SBS pellet-modified asphalt is mainly a physical mixing process. This work provides a scientific basis for further engineering applications of CR/SBS pellets. Full article

We report di- and triblock copolymers that combine hydrophilic polyethers—poly(ethylene glycol) monomethyl ether (mPEG) and polyglycidol (PGl)—with a hydrophobic, degradable polyester, poly(β-butyrolactone) (P(β-BL)). A mild hydrolysis method was developed to selectively remove acetal protecting groups from poly(ethoxy ethyl glycidyl ether) (PEEGE) without cleaving the β-butyrolactone polyester backbone, enabling the preparation of PGl-b-P(β-BL) and mPEG-b-PGl-b-P(β-BL) block copolymers. Thermal analysis revealed that the glass transition temperatures (T_g) of the copolymers could be tuned by varying block composition and length. Diblock copolymers containing the PGl segment were amorphous, with T_g values ranging from −2.7 to −19.9 °C. The presence of an mPEG segment in the triblock copolymers resulted in a further decrease in T_g, reaching values between −32.3 and −38.9 °C. Solubility and water affinity studies demonstrated that incorporation of hydrophilic polyether blocks enhances copolymer–solvent interactions, leading to increased wettability of the polymer-coated surface. The water contact angle for films formed from PGl-b-P(β-BL) decreased to 53 °C, while for mPEG-b-PGl-b-P(β-BL) copolymers, it was further reduced to 43 °C compared with the hydrophobic P(β-BL) film. Hydrolytic degradation experiments showed accelerated cleavage of the P(β-BL) segment in copolymers containing hydrophilic blocks compared to the P(β-BL) homopolymer, which is attributed to increased water accessibility and surface hydrophilicity. The most pronounced decrease in molar mass, reaching at least 50% relative to the initial non-degraded sample, was observed for the diblock copolymers, whereas the P(β-BL) sample showed only a marginal weight reduction of a few percent. Overall, this study demonstrates that the combination of hydrophilic mPEG and PGl blocks with P(β-BL) enables the design of block copolymers with tunable thermal properties, solubility, and degradation behavior, offering potential for a wide range of applications. Full article

PLLA-b-PEG-b-PLLA triblock copolymers are promising materials because of their highly tunable properties. However, a systematic understanding of composition–property relationships remains limited. In this study, a series of A-B-A triblock copolymers was synthesized with polyethylene glycol (PEG) as soft center (B) domains and poly(L-lactic acid) (PLLA) as hard end (A) domains via ring-opening polymerization. Copolymer composition and molecular weights were characterized by proton nuclear magnetic resonance spectroscopy (¹H NMR) and gel permeation chromatography (GPC). The thermal and mechanical properties of the copolymers were evaluated by differential scanning calorimetry (DSC) and tensile testing. We established quantitative structure–property relationships using empirical data, demonstrating that PLLA block length played a key role in modulating tensile properties, with a near-linear relationship, while PEG molecular weight critically influenced mechanical stability. An approximate minimum PLLA block length of 20 repeat units was found as a threshold required to maintain structural integrity during in vitro 24 h swelling. These findings provide insights and practical guidance for the design of triblock copolymers with tunable thermal, mechanical, and swelling properties of PLLA-b-PEG-b-PLLA triblock copolymers. Full article

Mechanochromism is a phenomenon in which mechanical stimuli change the optical properties of a material, such as its color and emission properties. Various materials exhibiting this behavior have been intensively studied. Mechanochromic materials that exploit liquid crystals have been previously reported. Using liquid crystals, properties different from those of conventional materials, such as anisotropic response and multicolored luminescence due to intermediate aggregation phase stabilization, can be expected. Recently, we reported the preparation and evaluation of the optical properties of liquid-crystalline mechanochromic dyes with cholesterol terminals. The dyes formed gels in some solvents, changed their emission color, and exhibited a friable response without reaching a crystalline state. In addition, film-forming properties, processability, and responsiveness were improved in thin films mixed with polymers. However, the mechanical and thermal stabilities of the gels were low. In this study, a compound similar to the polymerizable unit was synthesized to produce tougher gels. In addition, triblock polymers with a mechanoresponsive dye in the hard segment were synthesized. The xerogel film prepared from the monomer showed an irreversible blue shift in photoluminescent color by mechanical grinding and also exhibited linearly polarized photoluminescence by uniaxial grinding due to force-induced alignment. On the other hand, the xerogel film prepared from the triblock copolymer showed a blue shift in photoluminescent color that can approximately revert to the initial state by thermal annealing, though it showed no anisotropy by uniaxial grinding, indicating that polymerization partially preserves mechanical responsiveness. Full article

The development of biodegradable ABA-type triblock copolymers with tailored thermo-mechanical performance requires precise control over polymer architecture and phase behavior. In this study, PLLA-based ABA triblock copolymers were synthesized using two structurally distinct, fully bio-based soft segments: poly(methyl ricinoleate) (PMR) and poly(1,3-propanediol) (PPD). To the best of our knowledge, this is the first report on PLLA triblock copolymers incorporating PMR as a renewable soft middle block. Hydroxyl-terminated PMR and PPD were employed as macroinitiators for the controlled ring-opening polymerization of L-lactide, enabling systematic variation in block composition and molecular weight. Structural characterization confirmed successful block formation, while thermal and mechanical analyses revealed pronounced differences in phase separation and structure–property relationships. Copolymers containing PMR exhibited enhanced phase separation, increased crystallinity of PLLA domains, and significantly improved elongation at break, attributed to the presence of pendant chains in the soft segment. In contrast, PPD-based copolymers showed reduced phase separation and more PLA-like mechanical behavior. These results demonstrate that the chemical architecture of bio-based soft segments plays a decisive role in governing the thermo-mechanical performance of PLLA-based triblock copolymers. Full article

Inkjet printing technology shows significant potential for producing high-performance conductive circuits in printed electronics. However, conventional silver nanoparticle (Ag NP) inks often face challenges such as nozzle clogging, poor stability, and low conductivity after low-temperature sintering. While most existing studies focus solely on dispersant selection or individual process optimization, few have systematically explored the synergistic effects of particle size distribution, dispersion methods, and dispersant dosage. This study proposes a sequential optimization approach involving centrifugal classification to identify an optimal Ag NPs source and size distribution, followed by comparison and optimization of different dispersion methods. Furthermore, the effects of dispersant (a PEO-PPO-PEO triblock copolymer) concentration and application strategy (individual or combined use) on the rheological properties and conductivity of the ink were systematically investigated. The optimized Ag NP ink demonstrated excellent jetting stability with no nozzle clogging, exhibiting a surface tension of 19.60 mN/m and a viscosity of 6.83 mPa·s. After low-temperature sintering at 260 °C on glass or polyimide (PI) substrates, the printed patterns achieved a high electrical conductivity of 1.506 × 10⁷ S/m. Printing on polyethylene terephthalate (PET) at 150 °C confirmed compatibility with heat-sensitive flexible substrates. This work offers a comprehensive and practical strategy for developing highly reliable and conductive Ag NP inks, facilitating their application in next-generation printed electronics. Full article

Temperature-responsive hydrogels are sophisticated stimuli-responsive biomaterials that undergo rapid, reversible sol–gel phase transitions in response to subtle thermal stimuli, most notably around physiological temperature. This inherent thermosensitivity enables non-invasive, precise spatiotemporal control of material properties and bioactive payload release, rendering them highly promising for advanced biomedical applications. This review critically surveys recent advances in the design, synthesis, and translational potential of thermo-responsive hydrogels, emphasizing nanoscale and hybrid architectures optimized for superior tunability and biological performance. Foundational systems remain dominated by poly(N-isopropylacrylamide) (PNIPAAm), which exhibits a sharp lower critical solution temperature near 32 °C, alongside Pluronic/Poloxamer triblock copolymers and thermosensitive cellulose derivatives. Contemporary developments increasingly exploit biohybrid and nanocomposite strategies that incorporate natural polymers such as chitosan, gelatin, or hyaluronic acid with synthetic thermo-responsive segments, yielding materials with markedly enhanced mechanical robustness, biocompatibility, and physiologically relevant transition behavior. Cross-linking methodologies—encompassing covalent chemical approaches, dynamic physical interactions, and radiation-induced polymerization are rigorously assessed for their effects on network topology, swelling/deswelling kinetics, pore structure, and degradation characteristics. Prominent applications include on-demand drug and gene delivery, injectable in situ gelling systems, three-dimensional matrices for cell encapsulation and organoid culture, tissue engineering scaffolds, self-healing wound dressings, and responsive biosensing platforms. The integration of multi-stimuli orthogonality, nanotechnology, and artificial intelligence-guided materials discovery is anticipated to deliver fully programmable, patient-specific hydrogels, establishing them as pivotal enabling technologies in precision and regenerative medicine. Full article

CeO₂-ZnO nanocrystalline powders were prepared using Pluronic-assisted precipitation, followed by calcination at 500 °C. Different amounts of tri-block Pluronic copolymer (P123—2.5 g (P2.5), 5 g (P5), and 0 g (P0)) were used. PXRD, XPS, TEM, EDS, DRS, EPR, FT-IR spectroscopy, and the BET method were performed to determine the physicochemical characteristics of the prepared samples. They showed that the increased amount of P123 leads to an increased degree of crystallinity and polarity. The addition of the polymer in appropriate quantity plays a role as a structure-directing agent, thus preventing agglomeration processes and leading to changes in the structural features of the composites, which result in an increase in the band gap values. The adsorption edges of P0, P2.5, and P5 are 389.5 nm, 386.2 nm, and ~385.3 nm, which prove a blue shift. The photocatalytic discoloration of the Reactive Black 5 dye in the presence of all powders under UV-A illumination was studied. The P5 powder possessed the highest degree of discoloration (86% for 2 h illumination). These results could be assigned to the increased band gap value, polarity, and degree of crystallinity, as well as the increased quantity of Ce³⁺, oxygen vacancies, and hydroxyl groups of the Pluronic-modified powders. Full article

Polylactide (PLA) was melt blended with block copolymers of ethylene glycol and propylene glycol: a triblock copolymer (PPG-b-PEG-b-PPG) with a molar mass of 2700 g/mol and 40 wt% PEG content, and a diblock copolymer (PPG-b-PEG) with a molar mass of 4000 g/mol and 50 wt% PEG content. The structure as well as the thermal and mechanical properties of both amorphous and crystallized blends were investigated. Due to the copolymers’ chemical composition and the resulting phase structure, the 10 wt% amorphous blends with PPG-b-PEG-b-PPG and PPG-b-PEG, with T_g values of 38 °C and 46 °C, respectively, exhibited relatively high yield stress, close to 45 MPa, along with remarkable elongation at break. Notably, the blend with the triblock copolymer showed a 70-fold increase in elongation at break compared to neat amorphous PLA. Furthermore, the tensile impact strength of the blend with the diblock copolymer surpassed that of neat PLA. Upon crystallization, the 10 wt% blends showed reduced yield stress and elongation at break; however, the elongation at break exceeded 7–25 times that of neat crystalline PLA. Furthermore, their tensile impact strength increased to more than three times the value of crystalline PLA. Full article

Mesoporous silica materials with well-organized architectures were synthesized using a series of Pluronic PE-type triblock copolymers (PE6800, PE9200, PE9400, PE10500) as structure-directing agents under acidic conditions. The study aimed to elucidate the impact of synthesis parameters—copolymer type, presence of a swelling agent, 1,3,5-trimethylbenzene, aging temperature, and silica precursor—on the structural, textural, and functional properties of the resulting mesocellular foam materials. Characterization by Nitrogen Adsorption/Desorption, Transmission Electron Microscopy, X-ray Diffraction, and Small-angle X-ray Scattering revealed that structural ordering and pore morphology are significantly influenced by the EO/PO ratio of the copolymers and the use of the expander. Materials synthesized with PE9400 and PE10500 in the presence of a swelling agent exhibited highly uniform bottle-shaped mesopores with increased surface area and pore volume. Thermal behavior studied via Differential Scanning Calorimetry indicated a correlation between pore size and melting point depression of confined water, consistent with the Gibbs–Thomson effect. Adsorption capacity and kinetics for methylene blue varied significantly with pore structure, with materials possessing narrow mesopores showing superior dye uptake, and materials with larger mesopores and open-pore architecture exhibiting faster adsorption rates. This work demonstrates the tunability of mesoporous silica structure through precise control of synthesis conditions and highlights its potential in applications involving adsorption and phase phenomena in confined pore systems. Full article

In ophthalmology, developing effective drug delivery systems is crucial to overcome anatomical and physiological barriers, such as rapid tear turnover and blinking, which limit the efficacy of conventional formulations like eye drops. Poloxamers, especially the derivatives 407 (P407) and 188, are amphiphilic triblock copolymers characterized by an intriguing thermo-reversible behavior, making them ideal candidates for the development of in situ hydrogels for ocular applications. Various thermo-sensitive poloxamer-based hydrogels were designed to be easily instilled as liquids at room temperature, gelling promptly upon contact with the corneal surface. These systems promoted a controlled release of active compounds, significantly improving their adhesion to the ocular surface. This review discusses the most relevant scientific literature on the topic, with particular attention to studies published in recent years. The results demonstrated that poloxamer formulations are capable of overcoming typical ocular barriers, thereby increasing drug bioavailability. The intrinsic biocompatibility of poloxamers contributes to the safety and tolerability of the system. Furthermore, P407 showed additional wound healing features. The combination of biocompatibility and thermo-reversible behavior makes poloxamer-based hydrogels a promising platform for the development of innovative ocular drug delivery systems able to enhance therapeutic efficacy and patient comfort. Full article

Dry reforming of methane (DRM) is an effective strategy to simultaneously convert CH₄ and CO₂ into valuable syngas. However, the widely employed Ni-based catalysts often suffer from rapid deactivation due to metal sintering and deposited carbon under harsh conditions. Herein, Ni/Ce_0.2Zr_0.8O₂ catalysts were synthesized using the evaporation-induced self-assembly (EISA) method with the addition of the triblock copolymer surfactant P123. The addition of an appropriate amount of P123 improved the Ni dispersion; reduced Ni particle size; and enhanced the activation efficiency of both CH₄ and CO₂, thus increasing the reaction rate. In addition, the addition of P123 also enhanced the surface basicity and increased the concentration of oxygen vacancies of the catalyst, which enhanced its carbon removal capability and reduced deposited carbon. The catalyst with 0.2% P123 maintained excellent catalytic activity and stability for 300 min at 700 °C, with CH₄ and CO₂ conversion of 75% and 78%, respectively. These findings provide valuable guidance for the rational design of efficient and stable Ni-based catalysts for DRM. Full article

This study focuses on the synthesis and characterization of thermoresponsive hydrogels of poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG), PLA–PEG copolymers, aiming at the targeted and controlled release of deferoxamine (DFO), a clinically applied iron-chelating drug. Triblock (PLA-PEG-PLA) and diblock (mPEG-PLA) copolymers were synthesized using ring-opening polymerization (ROP) with five different PEGs with molecular weights of 1000, 1500, 2000, 4000, and 6000 g/mol and two types of lactide (L-lactide and D-lactide). Emulsions of the polymers in phosphate-buffered saline (PBS) were prepared at concentrations ranging from 10% to 50% w/w to study the sol–gel transition properties of the copolymers. Amongst the synthesized copolymers, only those that demonstrated thermoresponsive sol-to-gel transitions near physiological temperature (37 °C) were selected for further analysis. Structural and molecular confirmation was performed by Nuclear Magnetic Resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR), while the molecular weights were determined via Gel Permeation Chromatography (GPC). The thermal transitions were studied by calorimetry (DSC) and crystallinity via X-ray diffraction (XRD) analysis. DFO-loaded hydrogels were prepared, and their drug release profiles were investigated under simulated physiological conditions (37 °C) for seven days using HPLC analysis. The thermoresponsive characteristics of these systems can offer a promising strategy for injectable drug delivery applications, where micelles serve as drug carriers and undergo in situ gelation, enabling controlled release. This alternative procedure may significantly improve the bioavailability of DFO and enhance patient compliance by addressing key limitations of conventional administration routes. Full article

This study focused on the poly(DL-lactide-co-glycolide)-block-poly(ethylene glycol)-block-poly(DL-lactide-co-glycolide) (PLGA-PEG-PLGA) triblock copolymer, which was recently reported as a novel material for polymeric nanoparticles to replace poly(DL-lactide-co-glycolide) (PLGA) as a drug carrier for prednisolone (PSL), and aimed to evaluate the efficacy of PSL-loaded PLGA-PEG-PLGA nanoparticles (NPs) against allergic contact dermatitis (ACD). PSL-loaded PLGA-PEG-PLGA NPs were prepared using the nanoprecipitation method, and their particle size distribution and mean particle size were measured using dynamic light scattering. 1-Fluoro-2,4-dinitrobenzene (DNFB) was used to create a mouse model of contact hypersensitivity (CHS). PSL-loaded PLGA-PEG-PLGA NPs were administered before sensitization with DNFB, and the therapeutic effect was evaluated by quantifying intracutaneous TNF-α and IL-4 levels suing ELISA. When PSL-loaded PLGA-PEG-PLGA NPs were administered before sensitization, TNF-α expression and IL-4 statements were significantly lower in the PSL-loaded PLGA-PEG-PLGA NP group than in the non-treated group. No significant difference was observed between the PSL-loaded PLGA-PEG-PLGA NP and PSL-loaded ointment groups, even though the steroid dose was 40 times lower than in the PSL-containing ointment. These results suggest that PSL-loaded PLGA-PEG-PLGA NPs may have a better effect in the treatment of ACD than PSL-loaded PLGA NPs. Full article

Surfactants are widely utilized in agriculture as emulsifying, dispersing, anti-foaming, and wetting agents. In these adjuvant roles, the inherent biological activity of the surfactant is secondary to the active ingredients. Here, the hydrophilic non-ionic surface-active tri-block copolymer Pluronic^® F68 is investigated for direct biological activity in wheat. F68 binds to and inserts into lipid membranes, which may benefit crops under abiotic stress. F68’s interactions with Triticum aestivum (var Juniper) seedlings and a seed-borne Bacillus spp. endophyte are presented. At concentrations below 10 g/L, F68-primed wheat seeds exhibited unchanged emergence. Root-applied fluorescein-F68 (fF68) was internalized in root epidermal cells and concentrated in highly mobile endosomes. The potential benefit of F68 in droughted wheat was examined and contrasted with wheat treated with the osmolyte, glycine betaine (GB). Photosystem II activity of droughted plants dropped significantly below non-droughted controls, and no clear benefit of F68 (or GB) during drought or rehydration was observed. However, F68-treated wheat exhibited increased transpiration values (for watered plants only) and enhanced shoot dry mass (for watered and droughted plants), not observed for GB-treated or untreated plants. The release of seed-borne bacterial endophytes into the spermosphere of germinating seeds was not affected by F68 (for F68-primed seeds as well as F68 applied to roots), and the planktonic growth of a purified Bacillus spp. seed endophyte was not reduced by F68 applied below the critical micelle concentration. These studies demonstrated that F68 entered wheat root cells, concentrated in endosomes involved in transport, significantly promoted shoot growth, and showed no adverse effects to plant-associated bacteria. Full article