Contact Angle Test Research Articles

Electrospun PVDF/PVP Fibrous Membrane with Photocatalytic and Superhydrophilic Properties.

Membrane separation technology is used to treat environmental wastewater, but during the treatment process, the occurrence of membrane fouling greatly affects the treatment efficiency. To address this phenomenon, improve membrane antipollution capabilities, and treat organic wastewater, photocatalysis and membrane separation technology have been coupled, forming a suitable and promising treatment method. Here, we propose a simple strategy to prepare a polyvinylidene fluoride/polyvinyl pyrrolidone nitrogen-doped titanium dioxide fibrous membrane (PVDF/PVP N-doped TiO2 fibrous membrane). The experimental results showed that PVDF and PVP mixed spinning made the fibrous membrane have a unique microstructure, and the superhydrophobic PVDF fibrous membrane was changed into superhydrophilic. In addition, electrospraying technology was used to attach TiO2 nanoparticles (NPs) to the fiber, and nitrogen (N) was doped in this process to improve the photocatalytic activity of the fibrous membrane. Finally, methyl blue solution was used as the target organic pollutant. Under the irradiation of a xenon lamp, 90.05% of methyl blue was removed within 90 min, indicating that the membrane had good photocatalytic performance. In a water contact angle test, the PVDF/PVP N-doped TiO2 fibrous membrane showed superhydrophilicity. The design of a fibrous membrane with high photocatalytic activity and superhydrophilicity properties has great potential for practical application in the purification of industrial wastewater.

Enhancing Titanium Osteoconductivity by Alkali-Hot Water Treatment.

Titanium and its alloys are essential in orthopedic and dental treatments owing to their high strength, corrosion resistance, and superior biocompatibility compared with those of other metals. However, titanium alloys are bioinert. Previous studies have indicated that alkali treatment (AT) is a straightforward method to create a surface oxidization layer on titanium, thereby improving its bioactivity. Herein, alkali-hot water pretreatment was used to enhance the osteoconductivity of titanium and to identify a simple and efficient means of enhancing the interaction between osteoblasts and implants for clinical applications. Commercial pure titanium plates were ground (CP Ti) and subjected to alkali solution and hot water treatments (AWT). Single-process CP Ti specimens were prepared via either AT or hot water treatment (WT). Network-like structural features were observed in the AT specimens and were further refined and densified in the AWT specimens. Water contact angle testing revealed that the hydrophilicity of the titanium specimen (80° for CP Ti) increased by 19° for the AT specimens but decreased by 59° for the AWT specimens. Mouse preosteoblasts (MC3T3-E1 cells) were used for in vitro evaluation. After 24 h of culturing, the number of attached MC3T3-E1 cells on the AWT specimens was 1.5 times larger than that on the CP Ti specimens, suggesting that the alkali-hot water treatment enhanced the initial cell attachment. Cell proliferation evaluation indicated that fewer cells were detected in the AT and AWT specimens compared with those in the CP Ti or WT specimens. However, osteogenic differentiation evaluation on day 10 revealed a 1.5-fold higher alkaline phosphatase expression in cells cultured on the AWT specimens than in cells cultured on the CP Ti specimens. These findings demonstrate the good cytocompatibility and osteoconductivity of AWT Ti, highlighting its benefits in orthopedics and dental treatments.

Anti-icing and de-icing properties of composite superhydrophobic coating with microwave heating performance on asphalt pavement

Severe icing on asphalt pavements significantly impacts traffic safety and efficiency. Superhydrophobic coatings exhibit excellent hydrophobic and anti-icing properties, making them suitable for asphalt pavements. However, the formation of dense and hard ice limits their anti-icing effectiveness in cold regions. Within this paper, we have developed a novel composite superhydrophobic coating (CSC) with microwave heating performance by constructing a hierarchical structure using carbon nanotubes and incorporating micron-sized iron powder as a primary microwave-absorbing material. Scanning electron microscopy, 3D confocal microscopy, and contact angle tests reveal that the optimally mixed CSC possesses a complex micro-nano hierarchical structure, superhydrophobic properties (contact angle of 155.4°), and excellent anti-icing properties. Microwave heating results show that the CSC achieves a maximum heating rate of 1.108 ℃/s and an energy utilization efficiency of 47 %, representing improvements of 118.1 % and 18.3 % compared to uncoated specimens. Durability tests indicate that after wear, the CSC's contact angle decreases by 6.2 %, and the microwave heating rate drops by 13.7 %. Despite these reductions, the coating still maintains high hydrophobicity and microwave heating performance. While the friction coefficient of CSC-coated pavement decreases to μ=0.63, it still meets regulatory requirements. Overall, the application of CSC can effectively increase de-icing efficiency and mitigate the adverse effects of ice and snow on pavements.

Investigation of the effect and mechanism on the flotation performance of alkylglycine-based collectors by acyl group

The structure difference of the flotation reagent has a significant influence on its flotation performance. In this work, sodium N-lauroyl glycinate (SNG) was synthesized by introducing an acyl group into sodium N-dodecylglycinate (SN), and was using the collector in the oxide ores flotation. Properties of these two collectors were compared, and the effects behavior and mechanism of introducing the acyl group on the flotation performance of alkylglycine-based collectors to the zinc oxide minerals were systematically investigated. Flotation results proved that the introduction of C = O group into SN barely affected the floatability of smithsonite, hemimorphite and calcite, while the floatability of quartz was greatly reduced. Contact angle tests, surface tension tests, and froth collapse measurements indicated that the introduction of the acyl group into SN could selectively weaken its ability to improve the hydrophobicity of mineral surfaces, reduce its surface tension, adsorption capacity and intensity on the mineral surface, and the froth stability, thereby enhancing its selectivity, consistent with the flotation results. Fourier transform infrared spectroscopy (FTIR) analyses and density functional theory (DFT) calculations revealed that the introduction of the acyl group could increase the cross-sectional area and reduce the charge of the SNG polar groups to selectively weaken the adsorption interaction, particularly by significantly reducing the electrostatic adsorption between SNS and quartz surfaces. These also confirm that SNG is a promising highly selective collector for the flotation separation of zinc oxide minerals.

Polyethyleneimine assisted zeolitic imidazolate frameworks foam embed silver to enhance the uranium recovery from seawater

The powder structure, poor surface wettability and biofouling significantly limited the application potential of ZIFs (zeolitic imidazolate frameworks) in uranium extraction from seawater. Herein, a superhydrophilic polyethyleneimine assisted zeolitic imidazolate frameworks foam embed silver (CPEZ8A) was successfully prepared by simple chemical cross-linking and in-situ growth methods to explore the effects of hydrophilic matrix and silver antimicrobial agent on the uranium adsorption properties of ZIFs materials. The mechanical property and water contact angle test of CPEZ8A foam were performed to confirm its higher compression stress (with 1.314 MPa) and surface superhydrophilic. Moreover, CPEZ8A foam displayed an excellent resistance to biological attachment after 7 days in algae solution. Importantly, CPEZ8A showed the maximum U (VI) uptake capacity (775.19 mg/g) with 4.37 times of pure ZIF-8 at nearly seawater pH and retained relative high U-uptake amount during the broad pH range (4.0–9.0). Ion competition experiments were also investigated to verify the CPEZ8A foam excellent selectivity (Kd = 15,072.1 mL/g). Notably, the removal rate of CPEZ8A foam reach 81.31 % in natural seawater and remain nearly 80 % in simulated contaminated seawater. Therefore, this work provides an effective strategy to develop highly efficient ZIFs adsorbents for uranium capture.

Preparation and Properties Improvement of Decynediol-Ethoxylate-Modified Trisiloxane Surfactant.

Silicone surfactants are increasingly used in the industrial field due to their advantages such as low surface energy, stable performance, and good biocompatibility. However, many polyether-modified silicone surfactants' foam stability and easy hydrolysis in non-neutral aqueous systems limit their application in many fields. In this article, the decynediol-ethoxylate chain segment was grafted onto heptamethyltrisiloxane to synthesize a modified trisiloxane surfactant (G2). FT-IR and 1H NMR characterized its structure. Its surface activity, aggregation behavior, and wetting and spreading properties in water were studied by using instruments such as a surface tension meter, transmission electron microscope (TEM), dynamic light scattering (DLS), and contact angle tester. G2 can reduce the surface tension of water to 19.24 mN/m at a lower CMC (40.44 mg/L), and the foaming properties and hydrolysis stability of decynediol-ethoxylate-modified trisiloxane (G2) in water are significantly improved compared with allyl-polyoxyethylene-ether-modified trisiloxane (X5).

Preparation of Consolidated Dust Suppression Materials Based on Pectin: Graft Modification Experiment and Reaction Mechanism.

The natural material pectin was used as the matrix to prepare a dust suppressant. The regression model in response to the grafting ratio was established, and the optimum modification scheme was determined. The amount of monomer, initiator, cross-linking agent, and reaction temperature was 3.20 g, 0.20 g, and 0.15 g and 92 °C, respectively. Through Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy tests, not only the formation of the product in graft copolymerization reaction was validated but also the wettability of pectin was significantly improved. The surface morphology of pectin before and after modification was observed by a scanning electron microscope. After graft copolymerization treatment, the surface of pectin presented a dense grid structure, which proved that the pectin-modified dust suppressant can play a crucial role in wetting and condensing coal dust. Contact angle tests were used to characterize the effect of pectin modification on the wettability of bituminous coal before and after modification. The results of contact angle tests showed that when the droplets just contacted the bituminous coal flakes, the contact angle of modified pectin droplets on the flakes was the smallest, and the value was 55.21°. Compared with pure water droplets and unmodified pectin droplets, it decreased by 21.66° and 18.50°. The modification reaction process and dust suppression mechanism were explained at the molecular level.

Pepgen-P15 delivery to bone: A novel 3D printed scaffold for enhanced bone regeneration

Pepgen-P15 is a combination of an organic hydroxyapatite matrix derived from bovine sources, combined with a synthetic peptide known as P-15. The interaction between α2β1 integrin and the P15 chain triggers both intracellular and extracellular signaling pathways, resulting in the production of growth factors. Three-dimensional (3D) printing has recently emerged as an innovative strategy for developing personalized therapies in bone tissue regeneration. In this research, various ratios of calcium magnesium silicate (bredigite) nanoparticles were used to modify 3D printed scaffolds made of xanthan gum and polycaprolactone (PCL) via fused deposition modeling (FDM). Scaffolds were subsequently treated with an alkaline solution, covered with graphene oxide, and finally, Pepgen-P15 was applied. the effects of xanthan gum were assessed using swellability and contact angle tests. The results indicated that, the prepared scaffolds exhibited suitable degradation rates, mechanical characteristics, and apatite formation. Alizarin red and alkaline phosphatase assays were also conducted to evaluate the scaffolds’ effectiveness in promoting bone cell differentiation during cell culture. Furthermore, the surface of the scaffold was examined to determine the amount of Pepgen-P15 loaded and released. According to the findings, the scaffold composed of 20 % bredigite and 0.3 % graphene oxide, coated with Pepgen-P15, demonstrate optimal mechanical properties, cell adherence, development, and proliferation. Typically, it is a good candidate for use in bone tissue engineering.

Deep insight into the effect of smithsonite particle size on surface heterogeneity and adsorption behavior: A case of fatty acid system

The studies for microfine mineral flotation have focused on the two main directions of increasing the apparent mineral particle size and reducing the bubble size, while little research has been reported on the special surface properties and adsorption mechanisms of mineral particles of different sizes. In this study, sodium oleate was chosen as a typical surfactant. The mechanism of the effect of smithsonite particle size on the heterogeneity and adsorption behavior of the mineral surface was explored in depth. Through microflotation experiments, BET area tests, Washburn contact angle tests, particle agglomeration tests, adsorption tests and inorganic carbon analysis, it was pointed out that the smaller the size of the particles, the greater the surface wettability, and the smaller the density and thickness of adsorbed oleate on the surface. The difficulty of encapsulating the mineral surface with a hydrophobic layer of oleate hydrocarbon chains, as well as suboptimal particle aggregation sizes, are key reasons for the poor flotation behavior of fine smithsonite. Furthermore, the inhomogeneity of active sites and charge distribution of surface components of smithsonite with different sizes was revealed from a microscopic point of view by DRIFT spectroscopic analysis, XPS analysis and zeta potential measurements. As the particle size of smithsonite decreases, the positive charge density on the surface is higher and the hydration tendency is more intense, hindering the adsorption of oleate. This work is expected to guide the full particle size recovery of minerals in the flotation from a novel microscopic point of view.

Bioinspired Hydrophobicity via Temperature-Induced Phase Separation of Beeswax: A Pathway for Developing Cellulose Nanofiber-Based Adsorbents for the Removal of Conventional Tetracycline Tablets.

Cellulose nanofiber-based aerogels (CNFAs) hold immense promise across diverse fields, but their innate hydrophilicity and structural fragility in water have constrained their utility in water purification. This study introduces a green approach to induce hydrophobicity into CNFAs via thermally induced phase separation (TIPS) of beeswax, which was adhered to the nanofiber by hydrogen bonding and hydrophobic-hydrophobic interactions. The fabricated aerogel was characterized by using FTIR, SEM, XRD, TGA, contact angle, BET, and compression test. The resulting beeswax cellulose nanofiber-based aerogels (BCNFAs) possess a highly porous structure and extremely low density, enabling the aerogels to self-float and facilitate practical applications and recycling. Due to these remarkable characteristics, BCNFAs had excellent adsorption capacity within 10 min to effectively remove tetracycline (TC) from water with an adsorption capacity of 31.6 mg/g. The demonstrated methodology to induce hydrophobicity in CNFAs via TIPS of beeswax on CNFAs could be an eco-friendly and scalable approach for the fabrication of robust BCNFAs without using any toxic chemicals. So far, this is the first report on to make robust hydrophobic CNFAs by employing TIPS of beeswax while maintaining the porosity of CNFAs, which is highly desirable for effective TC tablet adsorption from water in the present context. The demonstrated work has commercial potential as it focuses on the practical utility of the modified aerogel for adsorbing conventional tetracycline tablets, rather than exclusively targeting the pharmaceutical ingredient alone.

Solanum tuberosum leaf extract as an eco-friendly corrosion inhibitor for Q235-steel in HCl medium: Experimental and theoretical evaluation

Solanum tuberosum leaf extract (STLs), used as a biodegradable corrosion inhibitor, was prepared to mitigate the corrosion rate of Q235 steel in HCl medium. The active inhibitory components existing in STLs were tracked by Fourier transform infrared spectroscopy. Electrochemical measurements, morphological characterization and contact angle tests were combined to evaluate the anti-corrosion performance of STLs at various concentrations and different temperatures, and the results show that the addition of STLs can evidently magnify the charge transfer resistance, expand the double layer capacitance at electric/solution interface, and simultaneously reduce the corrosion current density of Q235 steel in HCl medium with the maximum inhibition efficiency of 91.89 %. The adsorption behavior of STLs on steel was investigated using X-ray photoelectron spectroscopy and adsorption models. It is revealed that the molecules of STLs spontaneously bind to the substrate through chemical and physical action, forming a protective layer to block the diffusion pathway of harsh ions. Furthermore, theoretical calculations confirm that Solanum tuberosum leaves components were adsorbed on steel substrates through donor-acceptor interactions.

Effects of surface tension and contact angle on pore structure development of coal samples under chemical solution erosion

To explore the influence of surfactant concentration on the pore structure and permeability of coal samples during the chemical enhancement of coalbed methane production, different kinds and different concentrations of surfactants were added to the chemical solution, and the coal samples were soaked. Methods such as low-field nuclear magnetic resonance testing (NMR), fractal theory, permeability testing, surface tension testing, and contact angle testing were employed to analyze the variation patterns of coal sample pore structure, fractal characteristics, and permeability, and to explore the correlation between surface tension, contact angle, and the degree of pore structure development. The results show that the increase in total porosity of coal samples, the increase in the seepage pore porosity, the decrease in Dt, and the growth rate of permeability increase with the increase in surfactant concentration, and are negatively correlated with the surface tension of the solution and the contact angle of the coal-solution interface, while the decrease in Ds is not significantly correlated with surfactant concentration, surface tension, or contact angle. In terms of the erosion effect of a chemical solution on coal samples, the influence of contact angle is greater than that of surface tension, while surface tension has the greatest impact on the development of adsorption pores. By adding different surfactants, the surface tension of the chemical solution and the contact angle of the coal-solution interface can be controlled, further promoting the erosion of coal samples, which is of positive significance for the chemical enhancement of coalbed methane production.

Surface modification of ilmenite with sodium persulfate and its effect on flotation performance

Ilmenite is a challenging mineral to float, making the improvement of its floatability a prominent research focus. This study proposes a novel surface modification method using sodium persulfate (Na2S2O8) activation in the sodium oleate system for ilmenite. The activation mechanism was investigated using micro-flotation, zeta potential analysis, adsorption measurement, contact angle measurement, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), flotation kinetics calculation, and thermodynamic analysis. Flotation tests demonstrated a significant increase in ilmenite recovery after Na2S2O8 activation under weakly acidic conditions, particularly at pH 4.0, where recovery increased from 12.41 % to 67.24 %. Zeta potential, contact angle, and adsorption tests revealed that Na2S2O8 activation positively shifted the surface potential of ilmenite, enhancing sodium oleate adsorption and increasing hydrophobicity. FT-IR, XPS, and thermodynamic analyses showed that Na2S2O8 facilitated the conversion of Fe2+ to Fe3+ on the ilmenite surface. Additionally, activation with sodium persulfate increased the Fe3+ content on the surface from 20.13 % to 43.50 %, leading to the formation of a more stable ferric iron oleate. AFM scans confirmed that Na2S2O8 activation significantly increased the area and thickness of sodium oleate adsorbed on the ilmenite surface compared to unactivated ilmenite.

Rheological and adhesive improvements of terminal blend rubberized asphalt via fumed silica nanoparticle modification

Due to the high degree of desulfurization and depolymerization of crumb rubber (CR) particles in terminal blend rubberized asphalt (TBRA), their elasticity and adhesive performance are insufficient. To address this, the study utilized low-cost fume silica nanoparticles (FSNPs) to enhance the elasticity and adhesive properties. TBRA binders with varying CR contents (30 %, 40 %, 50 %) were modified using different dosages of FSNPs (2 %, 4 %, 6 %). The microstructure of FSNPs was examined through TEM and SEM. Using a dynamic shear rheometer (DSR) test, contact angle test, and atomic force microscope (AFM) test, the effects of FSNPs on the rheological properties, surface energy, and adhesive properties of TBRA binders were evaluated. The results showed significant improvements in the deformation resistance and elasticity of the TBRA binders modified with FSNPs. This is attributed to the branched network structure of FSNPs, which notably enhances the binder's cohesion, thereby strengthening its resistance to shear deformation and improving elasticity. FSNPs effectively reduce the moisture sensitivity of TBRA, due to the hydrophilic hydroxyl groups on FSNPs being replaced by hydrophobic methyl groups (-CH3). The inadequate bonding performance of TBRA can be attributed to the high levels of extensively depolymerized and desulfurized CR particles, which reduce the cohesiveness of the binder. The addition of FSNPs, although it lowers the surface energy of TBRA binders, significantly enhances their cohesiveness due to the branched network structure, thereby improving their bond performance. AFM results indicate that FSNPs enhance the adhesive strength of the TBRA binder surface due to their high specific surface area, which provides more van der Waals forces and electrostatic interactions. For economic efficiency, an addition of 4 % is recommended for TB30, and 2 % for TB40 and TB50. At these specified concentrations, the bond strength of the TBRA binder can be increased by 45–55 %.

Effect of rubber surface pretreatment method on the rubberized precast concrete

Abstract Disposal of waste tires is one of the environmental problems that require urgent attention. Their durability and potential for leaching out toxic chemicals have been a problem associated with disposal. This led many researchers to conduct studies on its potential for reuse. Among them is its potential as alternative to natural aggregates in concrete. However, rubber normally negatively affects the mechanical properties of concrete due to its hydrophobic nature resulting to poor adhesion with cement. In this study, the researchers explored the effects of different pre-treatment methods of rubber from waste tires to improve its hydrophilicity, its workability when mixed Type I Portland cement, and the mechanical properties of the resulting “rubberized” concrete. The pretreatment methods considered included: 1) soaking rubber in polyvinyl alcohol at different concentrations (8%, 10% and 12%); 2) soaking rubber in a mixture of sodium hydroxide, potassium permanganate, and saturated sodium bisulfite solution; and 3) exposure to UVA/B/C radiation. The rubber pieces from waste tires were first shredded into 0.3-0.5mm pieces prior to pretreatment. Hydrophilicity was measured through the contact angle test using an Optical Theta Lite Tensiometer. Workability of the concrete mix was measured through slump test (ASTM C143). The results show that rubber soaked in PVA 10% yielded the lowest contact angle (better hydrophilicity) and the most similar workability with normal concrete. Several concrete specimens using the pretreated rubber aggregates were then produced and cured for 7 days and 28 days before subjecting to several tests to determine the compressive, tensile, and flexural strengths. Pretreatment by soaking in PVA yielded concrete with mechanical properties comparable and in some instances better than normal concrete.

Application of Low-Temperature Air Plasma for the Enhancement of Defense Fabric's Self-Cleaning Property.

Self-cleaning textiles have the potential to revolutionize the lives of people like military personnel and hikers who spend extended periods of time in the sun and have restricted access to washing facilities. This research aims to develop the self-cleaning capability of defense uniforms by utilizing air plasma treatment and applying TiO2 nanocoating. Following plasma treatment of differing durations (2, 4, 6, 8, and 10 min, respectively), a pad-dry cure method was employed to apply a TiO2 coating to each sample, while keeping other processing parameters constant. SEM, Fourier transform infrared spectroscopy, ultraviolet protection factor (UVPF), energy-dispersive X-rays, and a water contact angle test were performed in order to validate the air plasma-induced surface modification. There was a gradual escalation in the rate of TiO2 absorption with an extension of the plasma treatment duration. Afterward, the samples were stained with various organic and inorganic compounds, including oil, ink, soil, and coffee, and subsequently exposed to sunlight for a period of 6 h. The samples demonstrated an enhanced cleaning effectiveness with increasing quantities of TiO2. The reflectance value and visual assessment of washed sample showed a reduced yet still present self-cleaning characteristic. The UVPF of the samples increased gradually as the duration of plasma treatment increased due to the UV absorption properties of TiO2, as validated by measuring the band gap energy.

Optimizing biomimetic hydroxyapatite coating on Ti-6Al-6Mo alloy: influence of immersion time

This study investigates the formation and characteristics of hydroxyapatite (HAp) coating on Ti-6Al-6Mo alloy through immersion in a supersaturated calcification solution (SCS) for 3, 7, and 14 days. X-ray diffraction (XRD) and secondary electron microscopy (SEM) with electron dispersive spectroscopy (EDS) were used to identify the phases and characterize the morphology and composition of the HAp layer. Atomic force microscopy (AFM) and contact angle tests were used to evaluate the surface properties, while potentiodynamic corrosion testing in Hanks’ solution was used to assess corrosion behavior. It is confirmed that the sample immersed for 14 days formed an HAp layer on the Ti-6Al-6Mo substrate with a Ca/P ratio of 2.5, approaching the ideal value of 1.67. This HAp film exhibits a smooth and homogeneous crystal structure, with a surface roughness of 31.47 nm and an appreciable corrosion rate of 0.0005 mm y−1. This study signifies the impact of immersion time on the microstructural properties and biocompatibility of biomimetic HAp coatings applied to Ti-6Al-6Mo alloy, contributing to the progress of HAp coatings in biomedical engineering.

Exploration on performance of the oxidized collector in the low-rank coal flotation

ABSTRACT Low-rank coal can be concentrated by flotation process using oxidized kerosene, which can improve flotation performance. However, the difference between oxidized kerosene and conventional collector with the same dosage on flotation performance is little known. In this study, the FTIR spectrum, GC-MS analysis and surfaces tension of collectors were analyzed for comparison the physical and chemical properties. The results showed the kerosene appearance of the short hydrocarbon chains with oxygen groups. The surface tension of kerosene is reduced by 21.99 mm/m after oxidation process. The contact angle and flotation tests were used for the kerosene, mixture including oxidized kerosene and kerosene with a mass ratio of 1:1, as well as oxidized kerosene for evaluating the performance. The results showed that the order of coal surface contact angle is that kerosene > mixture > oxidized kerosene. In addition, flotation tests revealed that mixture had superior flotation performance compared with kerosene and oxidized kerosene. The oxidized kerosene could significantly diminish the ash content of flotation concentrates, and the combustible matter recovery of clean coal with mixture is nearly 16.50% higher than that with kerosene. These results constitute a substantial step forward in technical development for resource recycling of low-rank coal.

Synthesis of Amphiphilic Polyacrylates as Peelable Coatings for Optical Surface Cleaning

Optical instruments require extremely high precision, and even minor surface contamination can severely impact their performance. Peelable coatings offer an effective and non-damaging method for removing contaminants from optical surfaces. In this study, an amphiphilic polyacrylate copolymer (PMLEA) was synthesized via solution radical copolymerization using the lipophilic monomer lauryl acrylate (LA) and hydrophilic monomers ER-10, methyl methacrylate (MMA), and butyl acrylate (BA). The structure and molecular weight of the copolymer were characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The hydrophilic–lipophilic balance, surface tension, and wettability of the copolymer were analyzed through water titration, the platinum plate method, and liquid contact angle tests. The cleaning performance of the copolymer coating on quartz glass surface contaminants was evaluated using optical microscopy and Ultraviolet-Visible Near-Infrared (UV-Vis-NIR) spectroscopy. The study examined the effect of varying the ratio of LA to ER-10 on the hydrophilicity, lipophilicity, cleaning efficiency, and mechanical properties of the copolymer coating. The results showed that when the mass ratio of LA to ER-10 was 1:2, the synthesized copolymer exhibited optimal performance in removing dust, grease, and fingerprints from quartz glass surfaces. The coating had a tensile strength of 2.57 MPa, an elongation at break of 183%, and a peeling force of 2.07 N m−1.

Polyglycerol Sebacate/polycaprolactone/reduced graphene oxide composite scaffold for myocardial tissue engineering

The aim of this research was to fabricate and evaluate polyglycerol sebacate/polycaprolactone/reduced graphene oxide (PGS-PCL-RGO) composite scaffolds for myocardial tissue engineering. Polyglycerol sebacate polymer was synthesized using glycerol and sebacic acid prepolymers, confirmed by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Six PGS-PCL-RGO composite scaffolds (S1-S6) with various weight ratios were prepared in chloroform (CF) and acetone (Ace) solvents at 8 CF:2Ace and 9 CF:1Ace volume ratios, using the electrospinning method at a rate of 1 ml/h and a voltage of 18 kV. The scaffolds' chemical composition and microstructure were characterized by FTIR, XRD, and scanning electron microscopy (SEM). Further investigations included tensile testing, contact angle testing, four-point probe testing for electrical conductivity, degradation testing, and cytotoxicity testing (MTT). The results showed that adding 2%wt RGO to the composite scaffold decreased fiber diameter and degradation rate, while increasing electrical conductivity and ductility. The 33%PGS-65%PCL-2%RGO (S3) composite scaffold exhibited the lowest degradation rate (23.87 % over 60 days) and the highest electrical conductivity (51E-3 S/m). Mechanical evaluations revealed an elastic modulus of 2.46 MPa and elongation of 62.43 %, aligning closely with the heart muscle's elastomeric properties. The contact angle test indicated that the scaffold was hydrophilic, with a water contact angle of 61 ± 2°. Additionally, the cell toxicity test confirmed that scaffolds containing RGO were non-toxic and supported good cell viability. In conclusion, the 33%PGS-65%PCL-2%RGO composite scaffold exhibits mechanical and structural properties similar to heart tissue, making it an ideal candidate for myocardial tissue engineering.