Colloid and Polymer Science最新文献

This study focuses on examining how the mechanical and wear properties are affected by the layer arrangement in hybrid laminates composed of natural fibers. Flax/glass fibers incorporated with epoxy composites and ZnO nanofillers were added at different weight percentages (0, 0.1, 0.3, 0.5 wt%). Compared to other composites, it was found that the flax/glass fiber composite filled with 0.3 wt% ZnO exhibited better tensile and flexural performances. The tribological characteristics of epoxy composites reinforced with glass and flax fabrics, including ZnO as a filler, were analyzed using the pin-on-disc method. The addition of these fillers significantly improves the tribological performance of epoxy composites reinforced with glass and flax fabrics, leading to a significant decrease in the wear rate. The heightened aspect ratio of ZnO contributes to an increased surface area of interaction, fostering improved adhesion between the epoxy matrix and the glass and flax fabrics. Taguchi’s experimental design was used to optimize the sliding distance, sliding velocity, filler content, fiber loading, and other input elements in the abrasive wear process. In addition, conventional weight measurements and wear surface morphology analyses were performed using FESEM. FESEM was used to determine the failure process of the worn surfaces of the filled composites.

To overcome the optical diffraction limit, combining micro-sized transparent spheres with photonic nanojet technology is able to achieve nanometer-level high-resolution imaging. To expand the imaging area, it is necessary to create a two-dimensional microsphere array. This paper presents a self-assembly method for fabricating two-dimensional transparent polystyrene microsphere arrays. The method uses radio frequency sputtering to deposit a low-friction graphite coating on the surface of a cured epoxy resin with a rippled structure. The wavelength of this rippled structure is slightly larger than the diameter of the polystyrene microspheres, allowing adjacent polystyrene microspheres in the one-dimensional array to make close contact. The amplitude of the rippled structure effectively prevents the polystyrene microspheres from flipping over. Next, 5 × 10^-6 wt% of polystyrene microspheres are uniformly dispersed in 100 mL of a cosolvent consisting of ethylene glycol and deionized water in an 8:2 weight ratio, and the colloidal solution is heated to 100 °C before being dropped onto the graphite-coated surface with the rippled structure. After the solvent evaporates, a single-layer, ordered arrangement of polystyrene microspheres can form.

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Ponceau 4R and amaranth are synthetic azo dyes commonly used in the food and beverage industry. However, excessive consumption of these dyes can pose potential health risks. This study describes a novel electrochemical sensor based on an electrochemical-reduced graphene oxide and silver (Ag-ErGO) modified gold electrode for the simultaneous determination of ponceau 4R and amaranth in soft drinks. The sensor was fabricated by electrochemically reducing graphene oxide and silver ion on a gold electrode (AuE). The morphology, structure, and composition of Ag-ErGO and graphene oxide on the gold electrode surface were characterized using SEM, IR spectroscopy, and EDS analysis. Adsorptive stripping voltammetry (AdSV) combined with cyclic voltammetry (CV) was employed to investigate the electrochemical behavior of ponceau 4R and amaranth. The optimal conditions were chosen to be Britton-Robinson buffer pH 2.0, adsorption potential 0.5 V, adsorption time 60 s, and scan rate 12.5 mV/s. The linearity ranges were from 0.0302 to 0.2418 mg·L⁻¹ and 0.0604 to 0.4836 mg·L⁻¹ with the detection limits 0.0074 mg·L⁻¹ and 0.0188 mg·L⁻¹ for simultaneously determination of ponceau 4R and amaranth, respectively. The proposed method was successfully applied to determine ponceau 4R and amaranth in soft drink samples.

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Membrane fouling is one of the most important issues in membrane studies and remains a current challenge. Therefore, developing composite membranes to reduce fouling is essential. In this study, delafossite-type CuMnO₂ and CuMnO₂-NH₂ nanostructures were synthesized and characterized in detail using various instrumental tools, including SEM, SEM-Elemental Mapping, P-XRD, BET, and FTIR. The biological properties of CuMnO₂ and CuMnO₂-NH₂ nanostructures, including antioxidant, antimicrobial, cell viability, antidiabetic activity, antibiofilm activity, and DNA fragmentation, were examined. Both materials exhibited good antioxidant, antimicrobial, and antibiofilm properties. The highest antioxidant activity for CuMnO₂ was 75.93% at 100 mg/L, while the highest antioxidant activity for CuMnO₂-NH₂ was 92.35% at 100 mg/L. The most effective MIC value of 16 mg/L was obtained for CuMnO₂ against Enterococcus hirae and Enterococcus faecalis. The highest amylase activity, at 165.2%, was observed at 100 mg/L for CuMnO₂. Both CuMnO₂ and CuMnO₂-NH₂ exhibited complete inhibition of microbial cell viability (100%) at 100 mg/L. Additionally, they demonstrated excellent biofilm inhibition activities against S. aureus and P. aureginosa. Furthermore, the use of polyethersulfone (PES) membranes coated with CuMnO₂ and CuMnO₂-NH₂ compounds for the eradication of Escherichia coli was investigated, along with the antibacterial activities of the membrane surface and permeate.

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Green cutting fluids (GCF) offer a desirable alternative to conventional synthetic cutting fluid by mitigating the negative effects on the environment while offering similar performance. This study aims to replace all the mineral-based contents of cutting fluid with eco-friendly plant-based alternatives. GCFs (B01 to B07) were formulated with coconut oil base, cocamidopropylbetaine (CAPB) as emulsifying agent with garlic oil as an EP/anti-wear additive and almond oil as a corrosion inhibitor. Characterization of formulated GCFs was carried out using FT-IR (Fourier transform infrared) and DSC (differential scanning calorimetry). Thermo-analytical studies provide important insights into thermo-physical characteristics influencing cutting performance. DSC results indicate a minor dip in the pour point of formulated GCFs. An overall increase in density, thermal conductivity and flash point of GCFs was observed. B03 showed an increase of 26.42% in thermal conductivity in comparison with virgin coconut oil (CO). The maximum increase of 12.03% in flash point was observed in case of B04. Excellent thermal stability was demonstrated by B02, B03 and B04, while most stable emulsions were observed for B03. Formulated GCFs exhibited significant improvement in corrosion inhibition. Considering overall enhancement in the properties of the formulated GCFs, the findings position blends B02, B03 and B04 as promising cutting-fluid replacements with a potential performance enhancement.

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Immunoassay is the most widely used detection technique in clinical testing. Compared with the traditional enzyme-linked immunoassay, the chemiluminescence immunoassay system based on carboxylated magnetic beads as the separation tool is more advantageous, which can rapidly separate proteins and achieve the purpose of quantitative detection of proteins. Separation tools in chemiluminescence immunoassay techniques are key and the focus of research. However, the domestic technology of preparing carboxylated magnetic beads is still immature, and the market is monopolized by imported products, which is not conducive to the development of domestic chemiluminescence immunoassay technology. Based on this, we propose a simple and convenient new method for the preparation of magnetic microbeads. Firstly, styrene-methyl methacrylate microspheres were polymerized by dispersion polymerization and hydrolyzed to form carboxylated microspheres, then carboxylated microspheres were introduced in the process of classical coprecipitation reaction to synthesize magnetic microbeads, and magnetic microbeads with different magnetic contents were prepared and characterized. The separation effect was then tested by a fully automated chemiluminescence immunoassay analyzer, and it was found that carboxylated magnetic beads with a magnetic content of 20% were the most effective in separating proteins, and the coefficient of variation was as low as 3.41%, with a stable and reproducible performance. The chemiluminescence immunoassay technique can separate proteins in a short period of time with a very small amount of carboxylated magnetic microbeads, which is fast and efficient and will help in the early diagnosis of diseases in healthcare facilities and may be a better point-of-care assay.

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Anisotropy can be effectively achieved with bilayer hydrogels, but the straightforward fabrication of actuated hydrogels with various stimulus responses is still difficult. This work describes the construction of temperature- and near-infrared light (NIR)-driven photosensitive bilayer hydrogels. In order to ensure that the prepared bilayers are tunable and have consistent mechanical properties, the bilayer hydrogels were prepared layer-by-layer, with poly(N-isopropylacrylamide) (PNIPAm) and poly(vinyl alcohol) (PVA) constructing the temperature-sensitive layer and poly(acrylamide) (PAAm) constructing the support layer. The highly effective photothermal conversion material Fe₃O₄@PDA, which has the best photothermal performance when the mass ratio of the two is 1:4, can be made by wrapping Fe₃O₄ in polydopamine (PDA). It was combined with the temperature-sensitive layer hydrogel to create a photosensitive hydrogel that could bend to 190° in 5 min when exposed to near-infrared light. The issue of the microscopic phase separation between Fe₃O₄ and the hydrogel is resolved by encapsulating Fe₃O₄ with PDA, which can make Fe₃O₄ uniformly disseminated in the hydrogel because it is not well diffused in the hydrogel. The photothermal effect is increased synergistically when the two are combined. Furthermore, it barely affects the hydrogel’s mechanical characteristics, which include a tensile strength of 27.65 kPa and a tensile strain of 253%. When exposed to laser light, the hydrogels demonstrated reversible bending motion. With the help of this creative method, remotely controllable light-responsive actuators may be made, creating new opportunities for applications in bioengineering and soft robotics.

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In this study, the effect of polyvinylpyrrolidone (PVP) polymer on lyotropic lamellar phases obtained using different types of surfactants, anionic and cationic, was compared. Three different methods were used to make these comparisons. The polarized microscope (POM) method was used to observe and compare morphological changes. It was observed that the texture structures of the lyotropic lamellar phases obtained by using anionic and cationic surfactants were different from each other. Structural changes were investigated by the small-angle X-ray scattering (SAXS) method. As the polymer concentration added to the lyotropic lamellar phase(s) increased, it was determined that the structural changes of the anionic and cationic samples were different from each other. While the polymer added to the anionic surfactant compresses the structure, the polymer added to the cationic surfactant does not significantly alter the structural parameters. The interactions of surfactant-polymer molecules with each other and their packaging were accordingly investigated by Fourier transform infrared spectroscopy (FTIR). How the polymer was added to the lyotropic lamellar phase and how the surfactant interacted with the chain and head groups was determined by examining the frequency shifts of the methylene chains and head groups. These frequency shifts provide information about trans-gauche transformations. The results indicate that the polymer added to both groups leads to a transition towards a gauche conformation. Both polymers and lyotropic lamellar phases have wide biological and technological uses. For this reason, their use together, that is, the interactions of polymer doped-lamellar phases, is interesting and should be understood.

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Nanogels offered a large surface area for biological conjugation due to their nanoscale size, enabling prolonged circulation in the bloodstream and targeted delivery to specific tissues. CMC/POM nanogels composed of 2-(2-(2-methoxyethoxy)ethoxy)ethyl methacrylate (MEO₃MA), methacrylic acid (MAA), and natural biopolymer carboxymethyl cellulose (CMC) were synthesized via free radical polymerization. The chemical structures of CMC/POM nanogels were characterized using several techniques, and the responsive behaviors under temperature and pH variations were reflected by changes in turbidity and particle size. The results demonstrated that CMC/POM nanogels exhibited significant changes in particle size and turbidity around 38 °C and under different pH conditions. Additionally, the unique microstructure of CMC/POM nanogels made them promising for drug delivery through injection therapy. With doxorubicin (DOX) as a model drug, the nanogels could achieve a maximum drug loading content of 31.47% and drug loading efficiency of 62.93%. During in vitro controlled drug releasing, the release efficiency was up to 92.20% within 24 h at T = 45 °C and pH = 3.0. The cytotoxicity assays confirmed that CMC/POM nanogels possessed superior biocompatibility and drug-loaded CMC/POM nanogels effectively inhibited the activity of cancer cells. CMC/POM nanogels displayed remarkable potential as intelligent drug delivery systems, and they were expected to play an essential role in the field of anticancer therapies.

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Rubber tends to adhere to molds during production due to its high viscosity at elevated temperatures, affecting product quality. The use of release agents facilitates the removal of rubber from molds, enhancing production efficiency and extending mold lifespan. With increasing emphasis on environmental protection, development and selection of high-performance, eco-friendly release agents have become pressing issues. This paper reviews recent advancements in rubber release agents, highlighting common features and selecting suitable surfactants for water-based, eco-friendly release agents. The study presents our recent progress in rubber release agents, comparing different surfactants used to formulate release agents. Particle size tests, emulsion stability tests, and release effect tests during tire production demonstrated promising results.