Assessment Of Wettability Research Articles

Enhanced biopolymer composites through micro-integrated lignin and anhydride modified nonwoven bast fiber

The growing need for sustainable materials in various industries has driven research towards eco-friendly biopolymer composites. In this study, lignin microfillers were integrated into PHBV/modified bast fiber matrices, offering a promising solution for sustainable material innovation with improved performance and functionality. Nonwoven bast fiber mats were initially treated with propionic, succinic, and maleic anhydrides, evaluated through weight gain analysis, chemical characterization, thermal stability, and wettability assessments. These modified bast fibers were then reinforced with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biopolymer at 30 % loading using specialized molding techniques. The resulting biocomposites were subjected to comprehensive characterization, including moisture related properties, mechanical strength, thermal behavior, and fracturographical properties. In a final stage, lignin microparticles (LMPs) as biofillers were integrated at 1 %, 3 %, 5 %, and 7 % concentrations to enhance biocomposite properties. Experimental findings highlighted succinylated bast fibers as offering the greatest improvements in mechanical strength, thermal stability, and morphological integrity among the modified fibers. At an optimal 5 % lignin microfiller content, the biocomposites exhibited superior wettability and improved stiffness. However, excessive lignin loading led to particle agglomeration, diminishing overall performance. Fracturographical analysis provided insights into the fracture behavior of the biocomposites, highlighting the cohesive and interfacial characteristics of the materials under stress conditions. This research highlights the efficacy of sequential modification strategies in developing high-performance sustainable materials tailored for diverse industrial applications.

Enhancement of wound dressings through cerium canadate and hydroxyapatite-infused hyaluronic acide and PVA membranes: A comprehensive characterization and biocompatibility study

This study explores the emhancement of advanced wound dressings by enhancing traditional bandages with suitable biomedical materials. We utilized Hyaluronic Acid (HA) and Polyvinyl Alcohol (PVA) as a polymeric matrix to create a novel membrane. Employing a film casting technique, we incorporated varying ratios of biological nanoparticles—Hydroxyapatite (HAP) and Cerium Vanadate (Ce₃(VO₄)₄)—to improve the wound dressing's properties. Wettability assessments provided insights into the surface characteristics of the scaffolds, revealing a diverse range of contact angles that reflect varying hydrophilic properties. Notably, the pure PVA/HA sample exhibited a contact angle of approximately 31.2° ± 12.1°, indicating excellent hydrophilicity and a strong capacity for drug absorption. However, the doping of nanoparticles resulted in an raise in contact angles, suggesting a slight reduction in hydrophilicity. Specifically, the addition of HAP produced a contact angle of about 36.5° ± 6.7°, while the addition of Ce₃(VO₄)₄ resulted in a contact angle of approximately 38.6° ± 6.4°. A significant increase in contact angle to 42.23° ± 4.8° was observed when mixing the nanoparticles, though the introduction of Graphene Oxide (GO) reduced the angle to 37.4° ± 0.35°, enhancing the hydrophilic properties of the composite. Cell viability testing was conducted to confirm the biocompatibility and bioactivity of the fabricated scaffolds. The results confirmed the ability of the scaffolds to promote cell growth, with an increase of 88.4 % in cell growth ratio observed at a suitable drug concentration of approximately 0.68 μg/ml. These findings highlight the potential of the developed scaffolds to enhance the wound healing process.

A new way to construct multifunctional superhydrophobic coating and applications in anti-corrosion, self-cleaning, membrane distillation and Water/Oil separation

Superhydrophobic materials have prospective applications in the field of self-cleaning, anti-corrosion and anti-fouling. However, the methods of preparing superhydrophobic surfaces usually have many disadvantages, and the scope of application is limited. Therefore, it is particularly important to adopt a widely applicable method to construct superhydrophobic surfaces. In this work, a general coating method has been used to fabricate superhydrophobic that polyaniline (PANI), titanium dioxide nanoparticles (TiO2-NPs) and 1H,1H,2H,2H-perfluorodecyltrie -thoxysilane (PDTS) has been chosen to modified polyimide nanofibrous membrane (PI NFM) (named as: PI-3). The PI-3 membrane exhibited a superior contact angle of 162˚ and ultralow adhesion of water droplets. Moreover, it not only displayed the properties of self-cleaning and anti-corrosion, but also had the broad application prospects in membrane distillation and oil/water separation. We conducted a series of tests, including contact angle measurement, roughness testing, wettability assessment, and oil-water separation performance evaluation. In the test of direct contact membrane distillation, it showed that the flux was always retained at beyond 10 L m−2 h−1 and the salt rejection was surpassed 99.26 %.

Eco friendly functional finishes of polyester fabric using keratin from wool and feather wastes

This research showcases the use of hydrothermally extracted solutions from poultry feathers and wool as eco-friendly and versatile textile finishes. These solutions, derived from waste biomass containing the keratin biopolymer, were obtained through environmentally conscious hydrothermal degradation processes. Initially, the study focused on analysing the chemical parameters and properties of both dialysed and non-dialysed solutions extracted from feathers and wool. The investigation tracked primarily the presence of keratin within these solutions. Upon application to polyester textiles as the reference material, the presence of these solutions on the fabric surface was confirmed successfully. A thorough physicochemical analysis of the treated textiles involved various analytical techniques. These encompassed surface composition analysis via X-ray Photoelectron Spectroscopy (XPS) and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), assessment of wettability through Contact Angle measurements, determination of surface charge using surface zeta potential, and examination of the thermal and flame-retardant properties via Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and calorimetric tests. In addition, the colour, UV radiation transmission and antioxidant activity were evaluated using standard tests.The remarkable effects of the treatment have been observed in the exceptional antioxidative action, fire resistance, UV protection and enhanced hydrophilicity of these innovative multifunctional textiles. This approach holds significant implications across research, economics and society, enriching Material Science by deepening the understanding of materials and their multifaceted properties. Moreover, it promotes resource efficiency, opens new sustainable textile market prospects, and contributes to social impact by supporting environmental sustainability, engaging communities and ensuring health and safety benefits.

Allylamine coating on zirconia dental implant surface promotes osteogenic differentiation invitro and accelerates osseointegration invivo.

The glow discharge plasma (GDP) procedure has proven efficacy in grafting allylamine onto zirconia dental implant surfaces to enhance osseointegration. This study explored the enhancement of zirconia dental implant properties using GDP at different energy settings (25, 50, 75, 100, and 200 W) both invitro and invivo. Invitro analyses included scanning electron microscopy, wettability assessment, energy-dispersive X-ray spectroscopy, and more. Invivo experiments involved implanting zirconia dental implants into rabbit femurs and later evaluation through impact stability test, micro-CT, and histomorphometric measurements. The results demonstrated that 25 and 50 W GDP allylamine grafting positively impacted MG-63 cell proliferation and increased alkaline phosphatase activity. Gene expression analysis revealed upregulation of OCN, OPG, and COL-I. Both 25 and 50 W GDP allylamine grafting significantly improved zirconia's surface properties (p < .05, p < .01, p < .001). However, only 25 W allylamine grafting with optimal energy settings promoted invivo osseointegration and new bone formation while preventing bone level loss around the dental implant (p < .05, p < .01, p < .001). This study presents a promising method for enhancing Zr dental implant surface's bioactivity.

Using an eco-friendly cold pad-batch reduction pretreatment to improve the whiteness, hydrophilicity, and anti-shrinkage of wool fabric

The presence of cuticle is the primary problem factor contributing to felting shrinkage, hydrophobicity, and yellowness in wool fabric. Substantial disulfide bonds forming cross-links within the scale layer result in an extraordinarily dense structure. During dyeing and finishing processes, the scale layer poses a significant barrier, impeding the efficient penetration of various chemicals. To mitigate the hindrance due to disulfide bonds in the scales, this study employed a cold pad-batch (CPB) reduction pretreatment followed by H2O2 bleaching to treat woolen fabrics. The physical, chemical, and mechanical properties of the treated wool were evaluated through scanning electron microscopy (SEM), Allwörden reaction, whiteness index measurement, wettability assessment, felting properties examination, dyeing performance analysis, Raman spectroscopy, and tensile testing. The results indicated a 23.50% increase in the whiteness index with minimal damage to the strength of the fabric. Furthermore, the water absorption time decreased from 300 s to 6 s, and felting shrinkage was decreased to <10%. These findings indicate significant improvements in the hydrophilicity and anti-felting properties of the wool. Additionally, SEM and Allwörden reactions demonstrated substantial changes in the morphology and structure of the fibers after the pretreatment, corroborated by dyeing performance results. Raman spectra exhibited that the relative content of disulfide bonds within the scale layer decreased from 30.95% to 20.95%. It saved more than 20% of water consumption and 70% of energy consumption. The combination process greatly improved the properties of wool fibers without further damage to the main body.

Exploring chitosan-plant extract bilayer coatings: Advancements in active food packaging via polypropylene modification

UV-ozone activated polypropylene (PP) food films were subjected to a novel bilayer coating process involving primary or quaternary chitosan (CH/QCH) as the first layer and natural extracts from juniper needles (Juniperus oxycedrus; JUN) or blackberry leaves (Rubus fruticosus; BBL) as the second layer. This innovative approach aims to redefine active packaging (AP) development. Through a detailed analysis by surface characterization and bioactivity assessments (i.e., antioxidant and antimicrobial functionalities), we evaluated different coating combinations. Furthermore, we investigated the stability and barrier characteristics inherent in these coatings. The confirmed deposition, coupled with a comprehensive characterization of their composition and morphology, underscored the efficacy of the coatings. Our investigation included wettability assessment via contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), which revealed substantial enhancements in surface concentrations of elements and functional groups of CH, QCH, JUN, and BBL. Scanning electron microscopy (SEM) unveiled the coatings' heterogeneity, while time-of-flight secondary ion mass spectrometry (ToF-SIMS) and CA profiling showed moderately compact bilayers on PP, providing active species on the hydrophilic surface, respectively. The coatings significantly reduced the oxygen permeability. Additionally, single-layer depositions of CH and QCH remained below the overall migration limit (OML). Remarkably, the coatings exhibited robust antioxidative properties due to plant extracts and exceptional antimicrobial activity against S. aureus, attributed to QCH. These findings underscore the pivotal role of film surface properties in governing bioactive characteristics and offer a promising pathway for enhancing food packaging functionality.

Surface Structuring of the CP Titanium by Ultrafast Laser Pulses

Surface structuring by ultrafast lasers is a promising technique to modify surface-related properties of materials to tailor them for specific applications. In the present study, we experimentally investigated the laser structuring of commercially pure titanium (CP Ti) using ultrafast pulses to understand the role of the laser input parameters on the development of surface morphology, optical properties, surface chemistry, and wettability behaviour. The processed surfaces were characterized by a scanning electron microscope, energy-dispersive X-ray spectroscopy (EDX), Raman microscope, optical microscope, and sessile drop method. Laser-induced periodic surface structures decorated with nanodroplets were noted to be formed on the surface of the laser-structured CP Ti. The surface roughness measurements showed that the laser-structured surfaces had nanoscale roughness values. The EDX and the Raman analyses show that laser-structured surfaces of CP Ti have a thin oxide film. Different colours on different surfaces processed by different laser parameters were observed. The wettability assessment shows that CP Ti can transition from hydrophilic–hydrophobic and vice versa depending on the environmental conditions. This study shows that laser structuring can be utilized to modify CP Ti surfaces to obtain desirable surface properties that can find potential applications in different fields.

Adaptable intelligent filters based on nanotextured nonwoven membranes containing water-insoluble hydrogels

The work demonstrates, for the first time, thermo-responsive, water-insoluble, hydrogel-based, nano-fibrous filter media comprised of copolymers of N-isopropylacrylamide (NIPAM) and methyl methacrylate formed by electrospinning. Moreover, a comprehensive novel physical explanation of all aspects responsible for the physical mechanisms resulting in the thermo-responsive regulation of the water flow rate and an enhanced interception of nanoparticles by such filter membranes is given. They are the wettable-non-wettable transition, pore, and fiber-size changes, as well as a diminishing filter thickness at the lower critical solution temperature (LCST) of the copolymers developed here, which interplay with a significant reduction in the water viscosity with temperature. Poly(N-isopropylacrylamide) (PNIPAM) hydrogel is an attractive material because of its thermo-responsive properties. Its wettability changes with water temperature. This characteristic holds great promise for the development of advanced filter media and related responsive materials. In this study, PNIPAM hydrogels were designed and transformed into filter membranes for applications in water filtration in biomedical and other related systems. These thermo-responsive filter membranes offer the potential for enhanced filtration efficiency, selectivity, and the overall system performance. Here, two different procedures were adopted to form water-insoluble thermo-responsive filter media based on PNIPAM hydrogels. The PNIPAM-based hydrogels were electrospun, resulting in the formation of thermo-responsive water-insoluble nanofiber membranes. These membranes underwent a series of comprehensive experiments to assess their performance and characteristics, including mass loss, water droplets for the wettability assessment, filtration tests, shrinkage measurements, and microscopic observations. These diverse experiments yield a full understanding of the PNIPAM-based nanofiber membranes’ properties and their potential applications.

Innovative Anodic Treatment to Obtain Stable Metallic Silver Micropatches on TiO2 Nanotubes: Structural, Electrochemical, and Photochemical Properties.

Electrochemical modification of the Ti surface to obtain TiO2 nanotubes (NT-Ti) has been proposed to enhance osseointegration in medical applications. However, susceptibility to microbial adhesion, linked to biomaterial-associated infections, and the high TiO2 band gap energy, which allows light absorption almost exclusively in the ultraviolet (UV) region, limit its applications. Modifying the TiO2 semiconductor with metals such as Ag has been suggested both for antimicrobial purposes and for absorbing light in the visible region. The formation of NT-Ti with Ag micropatches (Ag-NT-Ti) is pursued with the objective of enhancing the stability of the deposits and preventing cytotoxic levels of Ag cellular uptake. The innovative process proposed here involves immersing NT-Ti in a AgNO3 solution as the initial step. Diverging from previously reported electrochemical methods, this process incorporates anodization within the TiO2 oxide formation region instead of cathodic reduction generally employed by other researchers. The final step encompasses an annealing treatment. The treatments result in the in situ Ag1+ reduction and formation of stable and active micropatches of metallic Ag on the NT-Ti surface. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman, diffuse reflectance spectroscopy (DRS), wettability assessment, and electrochemical characterizations were conducted to evaluate the modified surfaces. The well-known properties of NT-Ti surfaces were enhanced, leading to improved photocatalytic activity across both visible and UV regions, significant stability against detachment, and controlled release of Ag1+ for promising antimicrobial effects.

Physics-informed neural network for solving Young–Laplace equation and identifying parameters

Capillarity is prevalent in nature, daily life, and industrial processes, governed by the fundamental Young–Laplace equation. Solving this equation not only deepens our understanding of natural phenomena but also yields insight into industrial advancements. To tackle the challenges posed by traditional numerical methods in parameter identification and complex boundary condition handling, the Young–Laplace physics-informed neural network (Y–L PINN) is established to solve the Young–Laplace equation within tubular domain. The computations on the classical capillary rise scenario confirm the accuracy of the proposed method on the basis of the comparison with Jurin's law, experimental data, and numerical results. Furthermore, the Y–L PINN method excels in parameter identification, e.g., contact angle, Bond number, and so on. These numerical examples even demonstrate its excellent predictive ability from the noisy data. For the complex boundary, it is rather convenient to obtain the liquid meniscus shapes in vessels, which is in good agreement with the experimental results. We further examine the variation of meniscus profile with wetting condition or discontinuous boundary. Importantly, the Y–L PINN method could directly solve the Young–Laplace equation with discontinuous wetting boundary without additional techniques. This work provides valuable insight for material wettability assessments, microstructure preparation, and microfluidics research.

Assessment of Kerogen Wettability from Contact Angle Goniometry

Assessment of Kerogen Wettability from Contact Angle Goniometry

Development of hydrophobic coating on 3D printed ABS samples and surface characterization

Manufacturers are increasingly substituting additive manufacturing for conventional manufacturing methods due to their ability to produce complex shapes. Polymer-based filament materials can be printed efficiently and inexpensively with fused deposition modeling. Coatings tend to augment the appearance of 3D printed objects as well as protect them from environmental influences. It is imperative to realize the physical and chemical properties of polymeric material like Acrylonitrile Butadiene Styrene (ABS) surfaces so as to design an optimal surface system. This work relates to the development of surface coatings on 3D-printed ABS parts. L9 orthogonal array was used with three 2 level factors for printing the samples. Specifically, the research compares surface characteristics of 3D-printed uncoated and coated ABS specimens. An aqueous solution containing Tricalcium phosphate and Chitin clear solutions in a 70:30 ratio was applied through immersion technique to create hydrophobic coatings. The coated and uncoated samples were characterized by employing various characterization tests, including dimensional accuracy (DA), surface roughness (SR), water contact angle (WCA), absorbency tests, scanning electron microscopy on fabricated parts. Assessment of wettability of 3D printed samples and impact of coating was accomplished via static contact angle measurements. In order to assess DA and SR before and after coating, digital vernier calipers were used in conjunction with a profilometer. In accordance with ASTM D570-98, water absorption tests were conducted for specified time. Results of investigation post coating showed no variation in dimensional accuracy, reduced SR and increased in WCA by ≥ 100 ̊. A reduction in water retention was observed after coating based on water absorption tests.

Systematic Assessment of Electrode Wettability for Vanadium Redox Flow Batteries

Vanadium redox flow batteries (VRFBs) are a promising energy storage technology due to their advantages such as long-life cycle and scalability. In these systems, porous electrodes such as carbon paper and carbon felts have been used because of their desirable properties such as good acid resistance and low cost. However, these materials may have poor reversibility and wettability, which can negatively affect the system performance. Recently, different activation methods have been proposed to enhance physico-chemical properties and overcome these limitations. Among different methods, surface treatments have been commonly used in the literature [1-5] since they can introduce desirable functional groups (e.g., oxygen, nitrogen) and enhance electrochemically active surface area (ECSA), which is believed to be the main mechanisms for electrode performance improvement. Although it is suggested that higher electrode performance can be achieved by enhancing wetted or active surface area [6], there is still a disparity in how to assess relevant wetting properties, since wettability assessment is often neglected and performance assessment is usually done based on VRFB cycling test results, which is costly and time consuming.Static contact angle (CA) is commonly used to characterize electrode wettability and evaluate the effect of different treatments on the electrode surface. However, this technique offers a limited understanding and superficial analysis, since samples are either classified as hydrophobic or hydrophilic, showing no correlation to electrochemical performance. Moreover, CA measurements are not adequate for porous electrodes, since porosity and surface roughness can impact on contact angle results. In the present work, we propose to use the method of standard porosimetry (MSP) and cyclic voltammetry (CV) to evaluate the impact of surface treatments on electrode wettability from a complete physical (pore size distribution), chemical (functional group density), and electrochemical (electrochemically active surface area) perspective. These tools offer richer information than basic CA measurements and only take a few hours to be performed, thus reducing the assessment time and cost compared to VRFB assembly and cycling tests.Preliminary results show that both MSP and CV techniques can provide useful information regarding physical and chemical properties that can correlate electrode wettability to electrochemical performance. While MSP results can provide electrode morphology (pore size distribution, porosity, specific and wetted surface area), CV measurements can provide surface chemistry information (functional groups density) and electrochemically active surface area (capacitance). Thus, both tools can be used synergistically to investigate how different treatments impact both physical and chemical properties and how wetting properties impact electrode performance. Achieving high performance is essential to increase system energy density and decrease both capital and operational cost, making VRFBs more competitive and suitable for grid-scale storage of renewable energy, having positive environmental impacts and facilitating sustainable transition. Acknowledgements This research was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), Canada Foundation for Innovation (CFI), British Columbia Knowledge Development Fund (BCKDF), Western Economic Diversification Canada (WD), Canada Research Chairs (CRC), and the National Research Council of Canada (NRC). Technical support from Elizabeth Fisher and Jonas Stoll is also acknowledged.

Characteristics of silver-dopped carbon nanotube coating destined for medical applications

Carbon nanotubes are materials demonstrating outstanding mechanical, chemical, and physical properties and are considered coatings of titanium implants. The present research is aimed to characterize the microstructure and properties of the multi-wall carbon nanotubes (MWCNTs) layer decorated with silver nanoparticles (Ag NPs) on the Ti13Nb13Zr alloy destined for long-term implants. The electrophoretic deposition of coatings was performed in a two-stage process, at first at 0.25 wt. pct. of MWCNTs, and next at 0.30 wt. pct. of Ag NPs content in the bath. The SEM, EDS, AFM, Raman spectroscopy, nanoindentation tests, nano-scratch test, wettability assessments, and corrosion tests were carried out. The effects of the presence of Ag NPs onto the MWCNTs coating were observed as the roughness increased to 0.380 µm and thickness to 5.26 µm, the improved adhesion and corrosion resistance, the water contact angle of 62.94°, the decreased nanohardness, Young`s modulus and resistance to plastic deformation under load, and slightly improved adhesion. The obtained results can be explained by a specific two-layer structure of the coating, in which the Ag NPs agglomerates create the coating less porous and permeable, but softer structure. Future research will focus on the improvement of the adhesion of the component coatings in different ways.

In vitro biological responses of plasma nanocoatings for coronary stent applications.

In-stent restenosis and thrombosis remain to be long-term challenges in coronary stenting procedures. The objective of this study was to evaluate the in vitro biological responses of trimethylsilane (TMS) plasma nanocoatings modified with NH3 /O2 (2:1 molar ratio) plasma post-treatment (TMS + NH3 /O2 nanocoatings) on cobalt chromium (CoCr) alloy L605 coupons, L605 stents, and 316L stainless steel (SS) stents. Surface properties of the plasma nanocoatings with up to 2-year aging time were characterized by wettability assessment and x-ray photoelectron spectroscopy (XPS). It was found that TMS + NH3 /O2 nanocoatings had a surface composition of 41.21 ± 1.06 at% oxygen, 31.90 ± 1.08 at% silicon, and 24.12 ± 1.7 at% carbon, and very small but essential amount of 2.77 ± 0.18 at% nitrogen. Surface chemical stability of the plasma coatings was noted with persistent O/Si atomic ratio of 1.292-1.413 and N/Si atomic ratio of ~0.087 through 2 years. The in vitro biological responses of plasma nanocoatings were studied by evaluating the cell proliferation and migration of porcine coronary artery endothelial cells (PCAECs) and smooth muscle cells (PCASMCs). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay results revealed that, after 7-day incubation, TMS + NH3 /O2 nanocoatings maintained a similar level of PCAEC proliferation while showing a decrease in the viability of PCASMCs by 73 ± 19% as compared with uncoated L605 surfaces. Cell co-culture of PCAECs and PCASMCs results showed that, the cell ratio of PCAEC/PCASMC on TMS + NH3 /O2 nanocoating surfaces was 1.5-fold higher than that on uncoated L605 surfaces, indicating enhanced selectivity for promoting PCAEC growth. Migration test showed comparable PCAEC migration distance for uncoated L605 and TMS + NH3 /O2 nanocoatings. In contrast, PCASMC migration distance was reduced nearly 8.5-fold on TMS + NH3 /O2 nanocoating surfaces as compared to the uncoated L605 surfaces. Platelet adhesion test using porcine whole blood showed lower adhered platelets distribution (by 70 ± 16%), reduced clotting attachment (by 54 ± 12%), and less platelet activation on TMS + NH3 /O2 nanocoating surfaces as compared with the uncoated L605 controls. It was further found that, under shear stress conditions of simulated blood flow, TMS + NH3 /O2 nanocoating significantly inhibited platelet adhesion compared to the uncoated 316L SS stents and TMS nanocoated 316L SS stents. These results indicate that TMS + NH3 /O2 nanocoatings are very promising in preventing both restenosis and thrombosis for coronary stent applications.

Influence of surface cleaning on the wettability of calcite/oil/brine systems

Contact angle (θ) is a measurement that characterizes the wettability of solid surfaces. Typically, contact angle measurements are conducted under one of the following conditions; cleaned rock surface, aged rock surface, or native (intact) rock surface. However, conventional cleaning agents such as toluene, acetone, heptane, and methanol may adsorb onto the rock surfaces and influence the wettability of the rock/oil/brine system. The effect of rock surface preparation using solvents prior to wettability assessments on rock/oil/brine systems is not systematically investigated. The influence of surface cleaning using solvents on the wettability of calcite/oil/brine systems was investigated. Calcite surface wettability was estimated via contact angle at high temperature (353 K) and pressures (0.1 to 50 MPa) before and after exposure to formation fluids and solvents. We have also conducted imaging and nanomechanical properties analyses of the rocks’ surfaces to investigate adsorption, change in surface chemistry and roughness, and mechanical properties of the rocks via Scanning Electron Microscopy (SEM), Scanning Probe Microscopy (SPM), nanoindentation, Fourier transform infrared spectroscopy (FTIR) and X-Ray Fluorescence (XRF) analysis before and after exposure. The results showed that these solvents get adsorb onto the rock surfaces and/or fail to completely remove the crude oil components from the rocks surfaces. Consequently, the wettability of the rock/oil/brine system is modified. Moreover, different contact angle values were observed for the same rock surface under different cleaning agents. Therefore, results from this study demonstrate that restoration of the initial rock wettability after fluids exposure was challenging as different rock surface cleaning prior to contact angle measurements results in different rock wettability.

Application of nuclear magnetic resonance method for qualitative assessment of rock wettability

Znajomość zwilżalności skał jest bardzo istotna, gdyż zjawisko to wpływa na ważne właściwości złoża, takie jak: nasycenie resztkowe ropą, względna przepuszczalność i ciśnienie kapilarne. Zrozumienie zwilżalności złoża ma kluczowe znaczenie dla określenia najbardziej efektywnych sposobów wydobycia ropy naftowej. W artykule przedstawiono metodę jakościowej oceny rodzaju zwilżalności skał, w której zasadniczą rolę odgrywają pomiary magnetycznego rezonansu jądrowego. Wykorzystuje się tutaj zróżnicowanie czasów relaksacji podłużnej T1, uwarunkowane rozkładem płynów w skale. Wykonanie badań wymagało użycia jednorodnego materiału skalnego. Badania zostały przeprowadzone na dwóch seriach próbek pobranych z dwóch bloków piaskowca: A (piaskowiec szydłowiecki biały) i B (piaskowiec szydłowiecki czerwony). Obydwa piaskowce charakteryzują się dużą jednorodnością, co potwierdzono pomiarami gęstości właściwej, gęstości objętościowej, porowatości helowej oraz badaniami na porozymetrze rtęciowym. Wykonano również standardowe pomiary czasów relaksacji poprzecznej T2 oraz wyznaczono skład mineralny dla reprezentatywnej próbki z piaskowca A i piaskowca B. Piaskowce te cechuje różny typ zwilżalności, co potwierdzono pomiarami współczynnika zwilżalności n standardową metodą elektryczną. W badaniach zastosowano dwa rodzaje płynów złożowych: solankę o mineralizacji 50 g/l oraz ropę naftową. W przypadku badania oddziaływania piaskowców z ropą naftową użyto dwóch rodzajów ropy o różnej lepkości dynamicznej: 7,43 mPa · s i 1,12 mPa · s. Skały nasycone ropą były przechowywane przez kilka dni w temperaturze około 65°C celem doprowadzenia ich do stanu zwilżenia ropą. Pomiary czasu relaksacji podłużnej T1 wykonano zarówno dla obu serii próbek skał, jak też dla zastosowanych płynów złożowych. Skały badano w stanie pełnego nasycenia, w stanie resztkowego nasycenia oraz po nasiąkaniu (ang. imbibition). Wykonane badania wykazały, że dystrybucja czasów relaksacji podłużnej T1 dobrze obrazuje rozkłady wody i ropy w skałach i może być wykorzystana do jakościowego opisu rodzaju zwilżalności.

Investigation of the Coupled Effect of IFT Reduction and Wettability Alteration for Oil Recovery: New Insights.

Interfacial tension (IFT) reduction and wettability alteration (WA) are both important enhanced oil recovery (EOR) mechanisms. In oil-wet formations, IFT reduction reduces the magnitude of negative capillary pressure, releasing trapped oil. WA changes the negative capillary pressure to positive conditions, helping the entrance of the aqueous phase, and the displacement of the oil phase. In most cases, IFT reduction and WA happen at the same time. However, studies regarding the coupled effect provided different, sometimes conflicting observations. It requires further study and better understanding. In our study, oil-aged Indiana limestone samples were chosen to represent oil-wet carbonate rocks. Static contact angle and spinning drop method were adopted for wettability assessment and IFT measurement, respectively. Spontaneous imbibition was adopted to reflect on the oil recovery mechanisms in different cases. The impact of IFT reduction, WA, and permeability on the coupled effect was discussed by choosing four pairs of comparison tests. Results showed that when the coupled effect took place, both a higher IFT value and a stronger WA performance resulted in faster and higher oil recoveries. The importance of IFT reduction was enhanced in the higher-permeability condition, while the importance of WA was enhanced in the lower-permeability condition.

Histological, Immunohistochemical, Biomechanical, and Wettability Evaluations of the Leukocyte- and Platelet-Rich Fibrin Membranes Derived from Canine Blood.

This study aimed to perform histological, immunohistochemical, biomechanical, and wettability assessments of leukocyte- and platelet-rich fibrin (L-PRF) membranes obtained from the blood of healthy dogs. Ten client-owned Labrador Retriever dogs were enrolled. Blood samples were obtained from the external jugular vein using a vacuum tube without anticoagulant, which was immediately centrifuged at 400g for 12 min in a dedicated centrifuge. The L-PRF clot was removed from the tube, and the red clot was released from the buffy coat using a spatula. The membrane was produced using a PRF box. Histological examination identified the three portions of the L-PRF membranes. The first portion was composed mainly of red blood cells with the presence of a low number of leukocytes among them. The second portion was composed of white blood cells, mainly neutrophils. The third portion was composed of the fibrin network which was characterized by acidophilic staining. The immunohistochemical analysis showed that vascular endothelial growth factor and platelet-derived growth factor were expressed in all samples at different intensities, both in cellular components and fibrin mesh. The tensile test and wettability assessments were measured in membranes 30 min and 3 h after production. The 30 min L-PRF membranes supported twice the ultimate tensile strength compared to 3 h L-PRF membranes. The wettability of the 30 min sample membranes was statistically higher than the 3 h sample membranes. In conclusion, the centrifugation protocol allowed production of the L-PRF membrane using canine blood and this was confirmed by histological and immunohistochemical analysis. The mechanical resistance and wettability of the L-PRF membrane were significantly reduced over time.