Surface Activity Research Articles

Interfacial Structures Associated with Surface Activity in Magnetic Devitrified Glasses for Biomedical Applications

Interfacial Structures Associated with Surface Activity in Magnetic Devitrified Glasses for Biomedical Applications

Combination of a MIP3α-antigen fusion therapeutic DNA vaccine with treatments of IFNα and 5-Aza-2'Deoxycytidine enhances activated effector CD8+ T cells expressing CD11c in the B16F10 melanoma model.

Previous studies in the B16F10 mouse melanoma model have demonstrated that combining a DNA vaccine comprised of regions of gp100 and tyrosinase-related protein 2 fused to Macrophage-inflammatory protein 3-alpha (MIP3α) with recombinant Interferon alpha (IFN) and 5-Aza-2'-Deoxycytidine (5Aza) treatments resulted in significantly greater anti-tumor activity and immunogenicity in the tumor microenvironment (TME). This brief report details that the combination of vaccine with treatments IFN and 5Aza results in both the upregulation of genes expressing CD11c-interacting proteins and an increase in the TME of a distinct CD11c+ CD8+ T cell population. This cell population correlates with tumor size, is primarily comprised of effector or effector memory T cells, and has a more robust response to ex vivo stimulation as compared to CD11c- CD8+ T cells as measured by surface activation markers 4-1BB (CD137) and KLRG1 (Killer cell lectin-like receptor G1) and intracellular IFNγ production. In conclusion, this combination therapy results in greater presence of highly active effector CD8+ T-cells expressing CD11c in the TME that correlate with and are likely primary contributors to treatment efficacy.

Combination of a MIP3α-antigen fusion therapeutic DNA vaccine with treatments of IFNα and 5-Aza-2'Deoxycytidine enhances activated effector CD8+ T cells expressing CD11c in the B16F10 melanoma model.

Previous studies in the B16F10 mouse melanoma model have demonstrated that combining a DNA vaccine comprised of regions of gp100 and tyrosinase-related protein 2 fused to Macrophage-inflammatory protein 3-alpha (MIP3α) with recombinant Interferon alpha (IFN) and 5-Aza-2'-Deoxycytidine (5Aza) treatments resulted in significantly greater anti-tumor activity and immunogenicity in the tumor microenvironment (TME). This brief report details that the combination of vaccine with treatments IFN and 5Aza results in both the upregulation of genes expressing CD11c-interacting proteins and an increase in the TME of a distinct CD11c+ CD8+ T cell population. This cell population correlates with tumor size, is primarily comprised of effector or effector memory T cells, and has a more robust response to ex vivo stimulation as compared to CD11c- CD8+ T cells as measured by surface activation markers 4-1BB (CD137) and KLRG1 (Killer cell lectin-like receptor G1) and intracellular IFNγ production. In conclusion, this combination therapy results in greater presence of highly active effector CD8+ T-cells expressing CD11c in the TME that correlate with and are likely primary contributors to treatment efficacy.

Synergetic control of multi‐level interface structure of basalt fibers by plasma and chemical functionalization to enhance the mechanical, thermal and interfacial performances of PBZ composites

AbstractThe composites of polybenzoxazine (PBZ) containing functionalized plasma treatment basalt fibers (fP‐BFs) were fabricated through in‐situ polymerization‐mixing technique. fP‐BFs is an effective reinforcement material that can improve the mechanical, thermal, and interfacial properties of composites. Surface activation of fP‐BFs can be enhanced through plasma modification, which improves the interaction between fP‐BFs and 3‐aminopropyltriethoxysilane. A systematic study on fP‐BFs/PBZ composite showed that a processing power of 300 W, a processing time of 5 min, and a fiber content of 9% can achieve good comprehensive mechanical properties. Thermogravimetric analysis results showed that fP‐BFs‐7/PBZ has the highest thermal stability, and its carbon residue rate, decomposition temperature and thermal decomposition activation energy are 36.80%, 452.2 °C and 133.56 kJ/mol, respectively. The dynamic mechanical analysis experiment showed that the addition of fP‐BFs improved the Tg of the composites. Among them, fP‐BFs‐5/PBZ showed the highest Tg, reaching 233.2 °C.Highlights Plasma treatment produced multi‐level structure of basalt fibers (fP‐BFs). Polybenzoxazine (PBZ)/fP‐BFs composites showed excellent performance. Interfacial bonding mechanism between fP‐BFs and PBZ was elucidated. Interfacial interactions between BFs and PBZ contributed to property enhancement. This work provided a green fabrication strategy of PBZ composites.

Extraction and Surface Activity of Australian Native Plant Extracts: Alphitonia excelsa

Saponin surfactants extracted from plants have significant potential applications in many industries. The interfacial properties of extracts of Alphitonia excelsa, a native Australian plant rich in saponins, have been characterised to assess their suitability as dual-purpose foaming and antibacterial additives. Two sources of the plant (Adelaide Botanic Gardens and homelands of Chuulangun Aboriginal Corporation) were investigated to look for alteration of properties as a result of differences in cultivation and geographic location. Two methods of saponin extraction (water and water/ethanol mixtures) were investigated to determine differences in extraction efficiency and performance. Distinct differences were observed between the traditional analytical analysis (for saponin content) of the extracts based on source and extraction method; however, these differences were not as stark when considering the effect of the extracts on air–water interfacial tension and dilatational rheology, with extraction method proving to be the single biggest factor in extract efficacy. The data obtained point toward the presence of an altered array of surface-active species (different relative amounts of particular saponins in the water/ethanol extracted material) as a function of the extraction method. All extracts presented some antibacterial effect, albeit modest. This work highlights that the extraction method needs to be carefully considered and tailored for a given application.

The promotion mechanisms of Mo for the dry reforming of methane reaction over a Mo-doped Ni(2 1 1) bimetallic catalyst

With the escalating severity of climate change, the DRM reaction has gained attention as an effective pathway for utilizing CO2. Enhancing reaction activity and identifying the sources of carbon deposition during the DRM reaction on Ni-based catalysts pose crucial yet challenging questions. In this study, we investigate the effects of Mo doping on the reaction activity and carbon deposition of Ni catalysts using a combined DFT and microkinetic method. In terms of the models, Mo replaced one Ni atom in the surface and subsurface layers to represent Mo in the initial stages and in prolonged on the reaction, namely NiMoU(211) and NiMoL(211). Through the analysis of electronic structure, intermediate structures, and reaction barriers compared with Ni(211), the impact of Mo doping on the surface activity and carbon deposition of Ni(211) is studied. The results indicate that the strong Ni-Mo interaction enhances intermediate stability, leading to increased reaction activity. Mo doping promotes the increase in O concentration, but at low temperatures, reaction rates decrease sharply. Furthermore, Mo doping enhances the resistance to carbon deposition on Ni(211) surfaces and improves the ability to remove carbon deposits, especially in prolonged reaction models. These findings provide new mechanistic insights into the DRM reaction on Ni(211) surfaces, which were previously well-explained by experimental results, and are valuable for understanding quantum processes.

Constructing coordination-connected flexible-rigid structures for the interfacial enhancement of CF/polyetheretherketone composites

Carbon fiber (CF) reinforced polymer composites have found widespread application due to their exceptional properties, including high specific strength and modulus, thermal stability, and chemical durability. However, since the interface serves as the bridge for load transfer between fiber and resin, the interfacial property directly affects the holistic performance of the composites. Considering the inertness of CF and polyetheretherketone (PEEK), as well as the modulus gap between them, we propose a flexible-rigid sizing agent to enhance the interfacial interaction. The sizing layers are constructed by the transition layer of polyetherimide (PEI) and the hybrid nanoparticles consisting of rare-earth coordination bonded flexible aramid nanofiber and rigid nano-TiO2. Calculated by density functional theory (DFT), the electron density difference (EDD) result displays the transfer of electrons between aramid nanofiber and nano-TiO2 acted by rare-earth element. This treatment with flexible-rigid sizing agent significantly improves the surface activity, roughness, and wettability of CF. Meanwhile, the flexural strength and interlaminate shear strength (ILSS) of as-prepared CF/PEEK composites are 91.4% (810.2 MPa) and 58.2% (82.6 MPa) higher than those of unmodified CF/PEEK composites. This work presents a robust and promising approach for fabricating high-performance CF/PEEK composites.

Surface Tension Manipulation with Visible Light through Sensitized Disequilibration of Photoswitchable Amphiphiles.

Azoarene isomerization lies at the heart of numerous applications, from catalysis or energy storage to photopharmacology. While efficient switching between their E and Z isomers predominantly relies on UV light, a recent study by Klajn and co-workers introduced visible light sensitization of E azoarenes and their subsequent isomerization as a tool coined disequilibration by sensitization under confinement (DESC) to obtain high yields of the Z isomer. This host-guest approach is, however, still constrained to minimally substituted azoarenes with limited applicability in advanced molecular systems. Herein, we expand DESC for the assembly of surfactants at the air-water interface. Leveraging our expertise with photoswitchable amphiphiles, we induce substantial alterations of the water surface tension through reversible arylazopyrazole isomerization. After studying the binding of charged surfactants to the host, we find that the surface activity differences upon visible light switching for both isomers are comparable to those obtained by UV light excitation. The method is demonstrated on a large concentration range and can be activated using green or red light, depending on the sensitizer chosen. The straightforward implementation of photoswitch sensitization in a complex molecular network showcases how DESC enables the improvement of existing systems and the development of novel applications driven by visible light.

Surface Tension Manipulation with Visible Light through Sensitized Disequilibration of Photoswitchable Amphiphiles

Azoarene isomerization lies at the heart of numerous applications from catalysis or energy storage to photopharmacology. While efficient switching between their E and Z isomers predominantly relies on UV light, a recent study by Klajn and co‐workers introduced visible light sensitization of E azoarenes and subsequent isomerization as a tool coined disequilibration by sensitization under confinement (DESC) to obtain high yields of the Z isomer. This host‐guest approach is, however, still constrained to minimally substituted azoarenes with limited applicability in advanced molecular systems. Herein, we expand DESC for the assembly of surfactants at the air‐water interface. Leveraging our expertise with photoswitchable amphiphiles, we induce substantial alterations of water’s surface tension through reversible arylazopyrazole isomerization. After studying the binding of charged surfactants to the host, we find that the surface activity differences upon visible light irradiation for both isomers are comparable to those obtained by UV light excitation. The method is demonstrated on a large concentration range and can be activated using green or red light, depending on the sensitizer chosen. The straightforward implementation of photoswitch sensitization in a complex molecular network showcases how DESC enables the improvement of existing systems and the development of novel applications driven by visible light.

Photothermal treatment-based heat stress regulates function of myeloid-derived suppressor cells

Photothermal therapy is an alternative cancer therapy that uses a photothermal agent with light irradiation to induce fatal hyperthermia in cancer cells. In a previous study, we found that ex vivo photothermal (PT) treatment induced expression of heat shock proteins (HSPs), such as HSP70, HSP27, and HSP90, in cancer cells; moreover, immunization with lysates from PT-treated tumor cells resulted in significant tumor growth inhibition in tumor-bearing mice. In this study, we hypothesized that sublethal PT treatment of antigen-presenting cells regulates their immunogenicity. We observed the upregulation of expression of intracellular HSP70 and surface activation markers, such as CD40, CD80, CD86, and MHC class II, in sublethal PT-treated cells. The protumoral activity of myeloid-derived suppressor cells (MDSCs) was reduced by sublethal hyperthermia. Furthermore, poorly immunogenic MDSCs were converted into immunogenic antigen-presenting cells by PT treatment. The differences in immunogenicity between MDSCs untreated or treated with the PT technique were evaluated using the Student’s t-test or Mann–Whitney rank sum test. Collectively, direct hyperthermic treatment resulted in phenotypic changes and the functional regulation of immune cells.

Unraveling the Potential of Vitamin B3-Derived Salts with a Salicylate Anion as Dermal Active Agents for Acne Treatment.

This study is focused on the utilization of naturally occurring salicylic acid and nicotinamide (vitamin B3) in the development of novel sustainable Active Pharmaceutical Ingredients (APIs) with significant potential for treating acne vulgaris. The study highlights how the chemical structure of the cation significantly influences surface activity, lipophilicity, and solubility in aqueous media. Furthermore, the new ionic forms of APIs, the synthesis of which was assessed with Green Chemistry metrics, exhibited very good antibacterial properties against common pathogens that contribute to the development of acne, resulting in remarkable enhancement of biological activity ranging from 200 to as much as 2000 times when compared to salicylic acid alone. The molecular docking studies also revealed the excellent anti-inflammatory activity of N-alkylnicotinamide salicylates comparable to commonly used drugs (indomethacin, ibuprofen, and acetylsalicylic acid) and were even characterized by better IC50 values than common anti-inflammatory drugs in some cases. The derivative, featuring a decyl substituent in the pyridinium ring of nicotinamide, exhibited efficacy against Cutibacterium acnes while displaying favorable water solubility and improved wettability on hydrophobic surfaces, marking it as particularly promising. To investigate the impact of the APIs on the biosphere, the EC50 parameter was determined against a model representative of crustaceans─Artemia franciscana. The majority of compounds (with the exception of the salt containing the dodecyl substituent) could be classified as "Relatively Harmless" or "Practically Nontoxic", indicating their potential low environmental impact, which is essential in the context of modern drug development.

The Gibbs and Butler Equations and the Surface Activity of Dilute Aqueous Solutions of Strong and Weak Linear Polyelectrolyte-Surfactant Mixtures: The Roles of Surface Composition and Polydispersity.

In a previous paper, we applied a combination of direct measurements of both surface tension and surface excess in conjunction with the Gibbs equation to explain features of the adsorption and surface tension of mixtures of surfactants and strong linear polyelectrolytes at the air-water interface. This paper extends that model by including (i) the restrictions of the Butler equation for the behavior of the surface tension of mixed systems and (ii) the surface behavior of surfactant and linear weak polyelectrolyte mixtures, for which the inclusion of measurements of the surface excess and composition is shown to be particularly important. In addition, a closer examination of earlier data at higher concentrations provides evidence that the surface layering that is often observed in polyelectrolyte-surfactant systems is also an average equilibrium phenomenon and is driven by particular aggregation patterns that occur in some systems and not in others. Although the successful application of the Gibbs and Butler equations indicates that strong polyelectrolyte-surfactant systems can be described in terms of an average equilibrium over wide ranges of concentration, we have identified two concentration ranges where polydispersity in either polyelectrolyte molecular weight or composition results in significant time dependence of the surface behavior.

Green preparation of nanoparticles with potential as nanocarriers for bioactive compounds using the valorisable biopolymers hyaluronic acid and hemoglobin

Proteins and polysaccharides are biopolymers that can be obtained from sustainable resources and can add value to biomaterials for medical and food science applications. Nanoparticles (NPs) of hemoglobin (Hb) and hyaluronic acid (HA) are prepared by electrostatic complexation of HA and Hb and thermal treatment at mild temperature under a totally biocompatible methodology. The electrostatic interaction between the anionic polysaccharide HA and Hb at conditions (pH 4) where the protein is strongly positively charged (net charge +54) is used to form protein/polysaccharide complexes of well-defined size distribution (100–200 nm). The complexes are stabilized against disintegration at pH 7 by thermal treatment at 60 °C for 2 h. The content of Hb in α-helices (∼47%) and β-sheets (∼19%) does not change upon thermal treatment. The NPs have pH-responsive surface charge and ability to bind hydrophobic compounds however the surface activity of the protein is not present in the NPs. This work motivates the use of renewable biomacromolecules from sustainable resources for nanocarrier applications.

Preparation of a colorimetric hydrogel indicator reinforced with modified aramid nanofiber employing natural anthocyanin to monitor shrimp freshness.

The pH-responsive hydrogels have potential applications in food visualization detection, but their fragile mechanical properties limit their applicability. The excellent mechanical properties and thermal stability of aramid nanofibers (ANFs) can improve the structural stability of hydrogels. In this study, the surface properties of ANFs were enhanced through modification to improve their surface activity. The modified ANFs, designated as ANF-SN, were produced following treatment with a mixture of sulfuric acid (H2SO4) and nitric acid (HNO3), which led to increased reactivity and dispersibility of the ANFs due to the proliferation of active groups on their nanofiber surface. The preferred anthocyanin extract from purple sweet potatoes (purple sweet potato extract [PSPE]) had significant color responses to pH (2-12) and ammonia vapor. A stable dual-network colorimetric hydrogel was fabricated by combining ANF-SN, polyvinyl alcohol/sodium alginate (PVA/SA), and PSPE through a two-step method (freeze-thawing and staining). Characterization analysis showed that the strong acid modification of ANFs effectively improved their chemical reactivity. ANF-SN was better than ANF in promoting the formation of hydrogen bond networks, enhancing hydrogel network structures, and improving the viscoelasticity of hydrogels. The optimal hydrogel indicator PVA/SA/ANF-SN/PSPE had good color responsiveness and sensitivity to ammonia. It can also be used to further determine shrimp freshness value using a smartphone and RGB color-picking software.

Enhanced removal of hazardous organic contaminants with advanced visible light-active F-doped TiO2/rGO/PVDF photocatalytic membranes

Polyvinylidene fluoride (PVDF) membranes and composite variants with x% FGT/PVDF photocatalytic membranes were prepared at different concentrations (x = 1 %, 5 %, and 10 %) using the phase inversion technique. The synthesized photocatalysts and the membrane materials were thoroughly characterized using different analytical methods. The focus was on determining the photocatalytic efficiency of these materials in degrading two important harmful dyes, namely methylene blue (MB) and crystal violet (CV), under visible light irradiation. High degradation percentages of MB (96 %) and CV (92 %) at 90 minutes were observed with 5 % F-TiO2/rGO (named as 5 %FGT). Similarly, the 5 % F-TiO2/rGO/PVDF (5 %FGT/PVDF) photocatalytic membranes showed 98 % and 93 % degradation of MB and CV, respectively. Kinetic studies revealed that the photocatalytic degradation reaction followed a pseudo-first-order mechanism. The total organic carbon (TOC) analysis of the treated MB and CV dyes showed a degradation of 78 % and 71 %, respectively. Recycling of the most active 5 % FGT/PVDF composite membrane exhibited very high stability of 800 min. The composite material utilizes the photocatalytic properties of TiO2 and the stimulating transport properties of rGO. Additionally, fluorine doping enhances charge carrier separation, tunes the bandgap for visible light response, and increases surface activity, thereby improving the overall degradation of organic pollutants. These properties make the composite material promising for various applications in environmental remediation and wastewater treatment.

A randomised clinical trial to arrest caries using silver diamine fluoride therapy with two postoperative instructions

ObjectiveThe objective of this study is to investigate the beneficial effect of not rinsing for 30 min in arresting early childhood caries after SDF therapy. MethodsThis randomised clinical trial recruited 3- to 4-year-old kindergarten children with active (soft) dentine caries. A questionnaire was sent to the parents to collect children's demographic data and oral health-related behaviours. A dentist conducted an oral examination and measured the caries experience using dmft index and oral hygiene using visible plaque index. After 38 % SDF therapy, the children were randomly allocated into two groups. Children in group A were instructed to rinse with water immediately, whereas children in group B were asked to refrain from rinsing, drinking, or eating for 30 min. After six months, the same examiner determined the lesion activity (active/arrest) of the SDF-treated carious tooth surface. Generalized Estimating Equations was used to compare the proportion of caries arrest (caries-arrest rate) between the two groups. ResultsThis study recruited 298 children with 1,158 decayed tooth surfaces receiving SDF therapy at baseline and evaluated 275 (92 %) children with 1,069 (92 %) SDF-treated tooth-surface at the six-month examination. The demographic background, oral hygiene and caries status of two groups were comparable at baseline (p > 0.05). The caries-arrest rate for group A and group B were 65 % (337/519) and 61 % (338/550), respectively (p = 0.28). ConclusionThis randomised clinical trial found not rinsing for 30 min after SDF therapy is not better than immediate rinsing in arresting early childhood caries. Clinical significanceTopical SDF application leaves an unpleasant taste in the mouth, which may affect the acceptance or even rejection of SDF therapy among young children. This study provides clinicians with information to make their decision on postoperative instruction after SDF therapy.

Near-Ambient Pressure Oxidation of Silver in the Presence of Steps: Electrophilic Oxygen and Sulfur Impurities.

The oxidation of Ag crystal surfaces has recently triggered strong controversies around the presence of sulfur impurities that may catalyze reactions, such as the alkene epoxidations, especially the ethylene epoxidation. A fundamental challenge to achieve a clear understanding is the variety of procedures and setups involved as well as the particular history of each sample. Especially, for the often-used X-ray photoemission technique, product detection, or photoemission peak position overlap are problematic. Here we investigate the oxidation of the Ag(111) surface and its vicinal crystal planes simultaneously, using a curved crystal sample and in situ X-ray photoelectron spectroscopy at 1 mbar O2 near-ambient pressure conditions to further investigate surface species. The curved geometry allows a straightforward comparative analysis of the surface oxidation kinetics at different crystal facets, so as to precisely correlate the evolution of different oxygen species, namely nucleophilic and electrophilic oxygen, and the buildup of sulfur as a function of the crystal orientation. We observed that emission from both surface and bulk oxide contributes to the characteristic nucleophilic oxygen core-level peak, which arises during oxygen dosing and rapidly saturates below temperatures of 180 °C. The electrophilic oxygen peak appears later, growing at a slower but constant rate, at the expenses of the surface oxide. Electrophilic oxygen and sulfur core-levels evolve in parallel in all crystal facets, although faster and stronger at vicinal surfaces featuring B-type steps with {111} microfacets. Our study confirms the intimate connection of the electrophilic species with the formation of adsorbed SO4, and points to a higher catalytic activity of B-type stepped silver surfaces for alkene epoxidation or methane to formaldehyde conversion.

A novel antibacterial and wear-resistant strategy based on metal surface micro-texture nitriding coupled functional mesoporous silicon coating

Modified metal layers coupling durable antifouling and antibacterial properties have garnered considerable interest in various fields, including but not limited to medical equipment, kitchen utensils, public facilities, and specific industrial applications, such as transportation, energy utilization, and aerospace. Nevertheless, wear and corrosion resulting from harsh operating environments can significantly compromise the modified metal layers, leading to diminished antifouling and antibacterial capabilities. Currently, maintaining excellent antibacterial properties on the surface of metal-modified layers under complex working conditions remains a key challenge for metal protection technology. Herein, we innovatively propose a ternary collaborative strategy to optimize and extend the antifouling and antibacterial activity of metal substrate surfaces. Firstly, laser surface texturing (LST) is used to create micro-textured topography on the metal surface to serve as a reservoir for collecting debris and storing functionalized nanoparticles. Then, the surface micro-textures are treated with plasma nitriding to form a wear-resistant passivation layer that protects the aforementioned microstructures. Finally, a lubricant containing functional mesoporous silicon nanoparticles (Ag2O-MSNs@OTES) is coated on the metal surface, which not only reduces the friction coefficient but also achieves antibacterial and antifouling effects by continuously releasing silver ions from the mesoporous silicon spheres. Employing the aforementioned ternary coordination strategy, the fabricated coupling layer exhibits not only exceptional antifriction and wear properties but also remarkable antibacterial efficacy against both E. coli and S. aureus, attributed to the Ag2O-MSNs@OTES. Therefore, the wear-resisting and antibacterial coupling layer for the protection of metal surfaces has promising and versatile applications in wide areas.

Age-dependent changes in phagocytic activity: in vivo response of mouse pulmonary antigen presenting cells to direct lung delivery of charged PEGDA nanoparticles

BackgroundCurrent needle-based vaccination for respiratory viruses is ineffective at producing sufficient, long-lasting local immunity in the elderly. Direct pulmonary delivery to the resident local pulmonary immune cells can create long-term mucosal responses. However, criteria for drug vehicle design rules that can overcome age-specific changes in immune cell functions have yet to be established.ResultsHere, in vivo charge-based nanoparticle (NP) uptake was compared in mice of two age groups (2- and 16-months) within the four notable pulmonary antigen presenting cell (APC) populations: alveolar macrophages (AM), interstitial macrophages (IM), CD103+ dendritic cells (DCs), and CD11b+ DCs. Both macrophage populations exhibited preferential uptake of anionic nanoparticles but showed inverse rates of phagocytosis between the AM and IM populations across age. DC populations demonstrated preferential uptake of cationic nanoparticles, which remarkably did not significantly change in the aged group. Further characterization of cell phenotypes post-NP internalization demonstrated unique surface marker expression and activation levels for each APC population, showcasing heightened DC inflammatory response to NP delivery in the aged group.ConclusionThe age of mice demonstrated significant preferences in the charge-based NP uptake in APCs that differed greatly between macrophages and DCs. Carefully balance of the targeting and activation of specific types of pulmonary APCs will be critical to produce efficient, age-based vaccines for the growing elderly population.Graphical

Effect of [C12mim][Cl]-NaCl compound solutions on pore structure and wetting characteristics of bituminous coal based on Pearson correlation coefficient

Water injection technology is a compelling technical measure to improve the water content of coal seams and reduce dust generation during mining. At present, the methods to enhance the wetting effect in the research progress are limited to increasing the dosage of a single wetting agent and using a variety of anionic and cationic wetting agents in large doses. More research is needed on the synergistic enhancement of the wetting effect by inorganic salts and ionic liquids. Aiming at this problem, this paper studies the influence of the combination of NaCl and surface active ionic liquid [C12mim][Cl] on the wetting effect and pore structure of bituminous coal. The influence of composite solution and ratio change on coal pore structure and wetting characteristics is studied based on Pearson correlation coefficient, combined with the experimental results of nitrogen adsorption at low temperature, scanning electron microscope and wetting characterization. The results show that bituminous coal exhibits different sizes of hysteresis rings after [C12mim][Cl] and NaCl treatments. With the change in composite ratio, the pore connectivity of coal samples is improved, and the surface roughness of modified bituminous coal is affected by the shift in composite ratio. With the enhancement of the wetting effect, the pore depth increases. On the other hand, adding 0.6 mol/L NaCl makes the composite solution reach a critical micelle concentration, which could synergistically enhance the surface activity and wetting effect of [C12mim][Cl] solution. There is a negative correlation between the volume of bituminous coal macropores and the contact angle, which indicates that the optimal solution ratio can be determined by analyzing the bituminous coal macropore volume change.