Sessile Drop Method Research Articles

Wetting and corrosion behavior of MgO substrates by CaO–Al2O3–SiO2–(MgO) molten slags

The corrosion of refractory is generally related to the wetting between slag and refractory. Investigating the wetting and corrosion characteristics of refractory by molten slag has a positive significance to elucidating the corrosion mechanism and understanding the slag resistance. In this work, the apparent contact angles of the CaO–Al2O3–SiO2–(MgO) molten slags on microporous magnesia aggregate (MM) and fused magnesia (FM) substrates were respectively measured by sessile drop method under Ar atmosphere at 1550 °C. The dissolution of the MM substrate and the slag penetration behavior were investigated by combining the theoretical calculation of the FactSage thermodynamic software with the examination of SEM-EDS. The results show that MM substrate had a better slag resistance than FM substrate. The final apparent contact angles (θf) of slags with the CaO/SiO2 values of 3, 5 and 11 on MM substrate were 15.8°, 21.4°, and 9.2°, respectively, and that with the MgO content of 3, 6 and 9 mass% were 11.1°, 14.2°, and 52.5°, respectively. The larger the CaO/SiO2 value of the slag, the more beneficial it was to slowing down the dissolution of MM and FM substrates; the original slag with MgO was also beneficial to lessening the dissolution of the MM substrate, which was better than that with a high CaO/SiO2 value. The formation of MA could inhibit the slag from penetrating. In addition, for slags with different CaO/SiO2 values, the effects of surface tension and viscosity on slag penetration were more significant than that of contact angle; for slags with different MgO contents, the effect of contact angle on slag penetration was more significant than those of surface tension and viscosity.

Wetting behavior and interfacial characteristics of Ti33Zr17Cu50 amorphous alloy on AlN

Our study investigated the wetting of AlN ceramic by molten Ti33Zr17Cu50 amorphous alloy at 1123–1223 K using a modified sessile drop method. Ti33Zr17Cu50 amorphous alloy presents an outstanding wettability and moderate reactivity. The spreading of the melts on AlN is controlled by the adsorption of Ti mainly and then forming TiN. The emergency of precursor film can be attributed to the high adhesive energy between Zr and TiN layer. Spreading dynamics put up two stages, the first stage is relative to the adsorption of Ti at the interface and further CuTi3 IMCs, and the second stage may correspond to the formation of a thin TiN layer. From the reasonable wettability point of view, it is difficult to fabricate excellent Ti-based amorphous alloy composites using AlN as a reaction agent to form TiN reinforcement in situ. Similarly, a favorable ceramic-ceramic or metal-ceramic joint can be obtained using Ti33Zr17Cu50 amorphous alloy as filler.

Measurement of the surface tension of liquid Ga, Bi, Sn, In and Pb by the constrained drop method

Abstract The effect of the droplet size on the accuracy of surface tension measurement by the sessile drop method is discussed for liquid metals through a simulation by using the Laplace equation. It is found that with increasing size of the droplet, a higher accuracy of the measured value of the surface tension can be obtained. In order to make a large droplet of liquid metals, the constrained drop method with a special crucible shape was applied to measure the surface tension of liquid Ga, Sn, Bi, In, and Pb. The uncertainty of the measured surface tension was within 1%. The temperature dependences of the surface tension of liquid Ga, Sn, Bi, In, and Pb were obtained in the present experiment as follows: Ga: σGa = 737 − 0.062T mN/m (823 ≤ T ≤ 993K) Sn: σSn = 579 − 0.066T mN/m (723 ≤ T ≤ 993K) Bi: σBi = 417 − 0.070T mN/m (773 ≤ T ≤ 873K) In: σIn = 600 − 0.082T mN/m (673 ≤ T ≤ 993K) Pb: σPb = 499 − 0.089T mN/m (757 ≤ T ≤ 907K)

Investigation of wetting behavior of Cr–Mn–Ni steels on hBN-SiC-ZrO2-substrate

The present study investigates the wetting behavior of Cr–Mn–Ni-alloys with TRIP/TWIP-effects on the hBN-SiC-ZrO2-substrate using the sessile drop method. The wetting behavior was studied in a 90 vol% N2/10 vol% H2 atmosphere in the temperature range of 1500 °C–1600 °C. Experiments were conducted in the reactive steel/ceramic system. Results demonstrate the effect of the nickel and the sulfur content on the contact angle between hBN-SiC-ZrO2-substrates and Cr–Mn–Ni-alloys. The increase in the nickel content from 3 to 9 mass% caused the increase of the contact angle from 129 to 138° at 1600 °C. Whereas, the increase in the sulfur content caused the decrease of the contact angle. The contact angle of the melts alloyed with the sulfur increases as the temperature rises. The increase in the contact angle was related to the evaporation of the manganese. In addition, the study discusses the chemical reaction between the hBN-SiC-ZrO2-substrate and Cr–Mn–Ni-alloys through (i) SEM-EDX investigations and (ii) thermodynamic calculations. The SEM-EDX analysis of the steel/ceramic interface shows the chemical degradation of the hBN-SiC-ZrO2-substrate. As a result of the reaction, a transition layer with a thickness of around 0.7 mm was formed in the hBN-SiC-ZrO2-substrate. To characterize the chemical reaction, thermodynamic calculations were conducted using the Thermo-Calc software. Results show that the chemical reaction was caused by the chemical instability of the SiC with regard to elements in Cr–Mn–Ni-alloys.

Morphology Influence on Wettability and Wetting Dynamics of ZnO Nanostructure Arrays

Abstract Changes in nanostructure morphology and size may result in very different surface wettability. In this research, the impact of different morphological parameters on the wetting dynamics of ZnO nanostructured layers is studied. Six different morphologies are chosen to determine the specific wetting processes of ZnO nanostructures: nanoneedles, small diameter rods, large diameter rods, nanotubes, nanoplates, and plain thin films. Wetting dynamics is investigated using conventional sessile drop technique and a novel approach based on electrochemical impedance spectroscopy. The results show that the surface of nanostructured ZnO thin films exhibits both hydrophilic and hydrophobic wetting behaviour, depending on nanostructure form, size, and orientation. ZnO nanostructure arrays are a promising platform for electrochemical and optical sensing in aqueous solutions. The full and effective use of the sensor working surface can be ensured only under the condition of complete wetting of the nanostructured layer. Therefore, it is important to take into account the peculiarities of the wetting process of a specific morphology of nanostructures.

Different surface treatment strategies on etchable CAD-CAM materials: Part 1—Effect on the surface morphology

Statement of problemPolymer-based computer-aided design and computer-aided manufacturing (CAD-CAM) materials have either a high content of ceramic filler particles or a ceramic network structure. Proper etching of these materials is challenging. Therefore, it is relevant to assess different surface etching strategies and morphological alterations as a result of these techniques. PurposeThe purpose of this 2-part in vitro study was to evaluate different etching strategies on the surface roughness and its relationship to the surface contact angle with a subsequent morphological characterization of different CAD-CAM materials. Material and methodsTwo CAD-CAM polymer-based materials and 1 CAD-CAM ceramic material were selected for this study. The materials were treated with different strategies, including a combination of airborne-particle abrasion and an application of 9% hydrofluoric acid etching. After the surface treatment, roughness measurements (Sa) were assessed by using an optical profilometer on an area of 1.47 mm2. Subsequently, the contact angle on the surface was examined by means of the sessile drop technique and an optical contact angle meter. The data were analyzed by using a 2-way analysis of variance, the post hoc Tukey test (α=.05), and the Pearson correlation coefficient. ResultsThe 3 materials tested showed an increase in surface roughness when treated with surface airborne-particle abrasion. However, the materials with polymer in their composition concomitantly increased the contact angle. More hydrophilic surfaces were observed when hydrofluoric acid was applied, regardless of the composition of the materials. The surface roughness presented a strong positive linear tendency in the surface treatments used. ConclusionsThe application of airborne-particle abrasion on the surface of the polymer-based CAD-CAM materials increased the roughness and contact angle. However, the application of acid etching after the airborne-particle abrasion decreased the contact angle for polymer-based CAD-CAM materials, resulting in considerable enhancement of the surface quality for proper bonding.

Influence of Selected Ophthalmic Fluids on the Wettability and Hydration of Hydrogel and Silicone Hydrogel Contact Lenses-In Vitro Study.

This study attempts to evaluate the effect of incubation in selected ophthalmic fluids on contact lenses (Etafilcon A, Omafilcon A, Narafilcon A, Senofilcon A). Four research groups differing in the incubation environment were created: (1) initial state, (2) contact lens solution (CLS), (3) contact lens solution and eye drops (ED) and (4) eye drops. Dehydration by gravimetric method and the contact angle (CA) by the sessile drop method were tested. The surface free energy (SFE) was also calculated with the use of several methods: Owens–Wendt, Wu, Neumann, and Neumann–Kwok. The greatest changes in the dehydration profile were observed for contact lenses incubated in ED. The most noticeable changes in CA values were observed for contact lenses incubated in ED, in which it was not possible to settle water drop after incubation. On the basis of SFE analysis, higher values were found for hydrogel contact lenses, e.g., according to the Owens–Wendt method, they ranged from 54.45 ± 6.56 mJ/m to 58.09 ± 4.86 mJ/m, while in the case of silicone-hydrogel contact lenses, they ranged from 32.86 ± 3.47 mJ/m to 35.33 ± 6.56 mJ/m. Incubation in all tested environments decreased the SFE values, but the differences were in most cases statistically insignificant. Calculating the SFE may be a useful method as it can be used to estimate the possibility of bacteria adhering to contact lens surfaces.

Live imaging of micro and macro wettability variations of carbonate oil reservoirs for enhanced oil recovery and CO2 trapping/storage

Carbonate hydrocarbon reservoirs are considered as potential candidates for chemically enhanced oil recovery and for CO2 geological storage. However, investigation of one main controlling parameter—wettability—is usually performed by conventional integral methods at the core-scale. Moreover, literature reports show that wettability distribution may vary at the micro-scale due to the chemical heterogeneity of the reservoir and residing fluids. These differences may profoundly affect the derivation of other reservoir parameters such as relative permeability and capillary pressure, thus rendering subsequent simulations inaccurate. Here we developed an innovative approach by comparing the wettability distribution on carbonates at micro and macro-scale by combining live-imaging of controlled condensation experiments and X-ray mapping with sessile drop technique. The wettability was quantified by measuring the differences in contact angles before and after aging in palmitic, stearic and naphthenic acids. Furthermore, the influence of organic acids on wettability was examined at micro-scale, which revealed wetting heterogeneity of the surface (i.e., mixed wettability), while corresponding macro-scale measurements indicated hydrophobic wetting properties. The thickness of the adsorbed acid layer was determined, and it was correlated with the wetting properties. These findings bring into question the applicability of macro-scale data in reservoir modeling for enhanced oil recovery and geological storage of greenhouse gases.

Wetting-state transition of random surfaces

Understanding the influence of topography on the wettability is essential to improve the modeling of superhydrophobic surfaces. Topography plays an integral role in the transition from a heterogeneous wetting state to a superhydrophobic wetting state. Herein, we report a significant experimental result, which is consistent with the theoretical formula that establishes the correlation between the surface and root mean square slope of surface structures. Moreover, this result allows one to study the influence of topography on the wetting-state transition, from the Wenzel to Cassie regimes. With this aim, hydrophobic and hydrophilic samples with graduated roughness were prepared. The topography and wettability were characterized by atomic force microscopy and the sessile drop technique, respectively. The experimental data fit the theoretical curve of the Wenzel roughness parameter as a function of the root mean square slope of the surface structures. Based on the contact angle, the slope range of the surface structure (0,49–1,04) was defined for the wetting-state transition. In addition, for the hydrophilic case, a divergence of the measured contact angle was noted in the Wenzel model, indicating a theoretical inconsistency.

Effects of repeated use of tungsten carbide burs on the surface roughness and contact angles of a CAD-CAM PMMA denture base resin

Statement of problemThe surface roughness (Ra) and wettability of complete denture base materials must meet certain clinical requirements. Although computer-aided design and computer-aided manufacturing (CAD-CAM) systems have recently become popular for the fabrication of complete dentures, the effects of the repeated usage of milling burs on the surface properties of CAD-CAM denture base acrylic resins have not yet been fully investigated. PurposeThe purpose of this in vitro study was to evaluate the effects of new and used burs on the Ra and contact angles (wettability) of a CAD-CAM polymethylmethacrylate (PMMA) denture base material. Material and methodsA total of 40 Ø2×10-mm disks were fabricated from 1 brand of CAD-CAM PMMA resin (Polident). Half of the specimens (group N) were milled with a new tungsten carbide bur set, while the other half (group U) was milled with a used tungsten carbide bur set. Moreover, half of the specimens (groups NT and UT) were subjected to thermocycling before Ra and contact angle testing. Ra was tested by using a profilometer, and the surfaces were also examined by scanning electron microscopy (SEM). The contact angle was measured by using the sessile drop method. Data were analyzed with the Kruskal-Wallis and Dunn Pairwise Comparison tests (α=.05). ResultsThe mean contact angle was highest for group U (80 degrees) and lowest for group UT (66 degrees) (P<.05). Ra values were highest for group N (1.3 μm) and lowest for group U (0.93 μm) (P<.05). ConclusionsSpecimens milled with new tungsten carbide burs had lower mean contact angles and higher Ra values than specimens milled with used burs. The contact angles of CAD-CAM PMMA resin specimens milled with used burs decreased significantly after thermocycling. Regardless of whether or not thermocycling was performed, contact angle values decreased as Ra values increased.

Reactivity with tin and corrosion resistance of electroless Ni-P and Ni-P-Re coatings plated on copper

The electroless plated nickel (Ni-P) layers are widely applied in the electronics industry (ENIG coatings), where the quality of interconnections is directly related to the nickel solution and the resultant chemical composition (phosphorus content) of the coating. Depending on the concentration of phosphorus within the coating, the layer can be either fully amorphous or with nano Ni crystallites or crystalline. This translates into an increase of the temperature of its thermal stability, which directly impacts the processes occurring at elevated temperatures during the soldering process or later during the use of the final product (heating/cooling conditions). This work shows how the metallization/solder zone is transformed after their reaction, where, as the solder material pure tin was used, being the main component of currently used lead-free solder of SAC type. In the electronics industry, the typically used coatings have a phosphorous content in the range of 6–8 wt.%. Therefore, the coatings of also such compositions have been studied. The newly electroless plated coatings were first characterized in terms of surface morphology and chemical composition. Then, the interfacial reactivity between liquid Sn and coatings was studied using the sessile drop method, and the resulting substrate/coating/solder reaction zone was examined by scanning and transmission electron microscopy. The main goal of the research was to determine the quality of the interface, the width of the newly formed zones, and the presence of NixPy phases as well as the intermetallic phases formed as a result of the reaction. The addition of rhenium to Ni-P coatings inhibited the formation of the Ni2SnP phase in each of the tested phosphorus content ranges (low, medium, and high phosphorus), also after thermal cycles. Thus, no undesirable phenomenon of intermetallic phase detachment from the layer/solder interface was observed. Studies have shown that the corrosion resistance of samples increases as the pH of the solution from which the test coatings are deposited decreases, and the addition of rhenium to Ni-P coatings always improve their corrosion resistance.

The Effect of Ultraviolet Treatment on TiO2 Nanotubes: A Study of Surface Characteristics, Bacterial Adhesion, and Gingival Fibroblast Response

Titanium dioxide (TiO2) nanotubes are emerging as a provocative target for oral implant research. The aim of this study was to evaluate the effect of UV on the wettability behavior, bacterial colonization, and fibroblast proliferation rate of TiO2 nanotube surfaces prepared using different anodization voltages and aimed for use as implant abutment materials. Four different experimental materials were prepared: (1) TiO2 nanotube 10 V; (2) TiO2 nanotube 15 V; (3) TiO2 nanotube 20 V; and (4) commercial pure titanium as a control group. TiO2 nanotube arrays were prepared in an aqueous electrolyte solution of hydrofluoric acid (HF, 0.5 vol.%). Different anodization voltages were used to modify the morphology of the TiO2 nanotubes. Equilibrium contact angles were measured using the sessile drop method with a contact angle meter. The investigated surfaces (n = 3) were incubated at 37 °C in a suspension of Streptococcus mutans (S. mutans) for 30 min for bacterial adhesion and 3 days for biofilm formation. Human gingival fibroblasts were plated and cultured on the experimental substrates for up to 7 days and the cell proliferation rate was assessed using the AlamarBlue assayTM (BioSource International, Camarillo, CA, USA). The data were analyzed using one-way ANOVA followed by Tukey’s post-hoc test. Water contact angle measurements on the TiO2 after UV treatment showed an overall hydrophilic behavior regardless of the anodization voltage. The ranking of the UV-treated surfaces of experimental groups from lowest to highest for bacterial adhesion was: TiO2 nanotube 20 V &lt; Ti and TiO2 nanotube 15 V &lt; TiO2 nanotube 10 V (p &lt; 0.05), and for bacterial biofilm formation was: TiO2 nanotube 20 V-TiO2 nanotube 10 V &lt; Ti-TiO2 nanotube 15 V (p &lt; 0.05). Fibroblast cell proliferation was lower on TiO2 nanotube surfaces throughout the incubation period and UV light treatment showed no enhancement in cellular response. UV treatment enhances the wettability behavior of TiO2 nanotube surfaces and could result in lower bacterial adhesion and biofilm formation.

The control of ITO conductive coating relief via laser-oriented deposited carbon nanotubes

The paper presents the analysis of the surface relief of ITO conductive layers structured with single-walled carbon nanotubes. The deposition of ITO films and carbon nanotubes was carried out by laser-oriented method using a CO2 laser. The optical scheme was matched to the control electric grid; the strength of the electric field was varied in the range of 100–600 Vcm–1. To analyze the surface, atomic force microscopy in the contact mode and measurement of the wetting angle by sessile drop method was used. Roughness of pure ITO was about 1.8 nm, while in laser-vacuum deposition of carbon nanotubes, roughness varied from 6.4 nm to 22.1 nm with an increase in the electric field during deposition. The relationship between roughness and surface area of coatings and the wetting angle was considered. An increase in the wetting angle from 101.8 degrees, in the case of pure ITO, to 115.0-128.6 degrees, with the deposition of carbon nanotubes, was shown. The results obtained indicate an improvement in the resistance of ITO coatings to moisture during the deposition of carbon nanotubes, which makes it possible to expand their operating conditions and scope in optical electronics, laser and display technology.

Antifungal Activities and Some Surface Characteristics of Denture Soft Liners Containing Silicon Dioxide Nanoparticles.

ABSTRACTObjective:This study aimed at determining the influence of adding silicon dioxide nanoparticles (nano-SiO2) to soft relining materials on C. albicans adhesion, surface roughness, and contact angle.Materials and Methods:Eighty heat-polymerized acrylic resin disks were constructed and relined by using auto-polymerized acrylic soft liners (COE-SOFT, GC Co., Tokyo, Japan). The specimens were categorized into two groups according to the tests conducted. Group A was composed of 40 specimens for evaluating antifungal activity, and Group B was composed of 40 specimens for testing surface roughness and contact angle. Each group was subcategorized into four subgroups (n = 10) according to the concentration of nano-SiO2 added to the soft-liner powder: control, 0.25%, 0.5%, and 1.0% by weight. The colony forming unit (CFU) was used to assess C. albicans count. A profilometer was used to measure the surface roughness values (Ra; μm). The sessile drop method was used to evaluate the contact angle (o) by using a goniometer. Analysis of variance and Tukey’s post hoc tests (α = 0.05) were used for the data analysis.Results:In comparison with the unmodified group, the 0.25% and the 0.5% nano-SiO2 groups exhibited significantly lower C. albicans counts (P < 0.001), surface roughness (P < 0.001), and contact angles (P < 0.001). The exception was the 1% group, which exhibited higher C. albicans count, surface roughness, and contact angles than lower-concentration nano-SiO2 groups; however, these values in the 1% group were still less than their respective values in the control group.Conclusion:The addition of 0.25% and 0.5% nano-SiO2 to an auto-polymerized acrylic soft liner decreased C. albicans adhesion, surface roughness, and contact angle.

Influence of Mixing Conditions of Modified Bitumen on Moisture Sensitivity of Asphalt Compounds

Modification of bitumen allows an improving the properties of bitumen, which can be a useful technique to enhance asphalt’s characteristics. Therefore, this research intended to study the effect of mixing time of different percentages of epoxy resin, between 0 to 8%, doped into bitumens on the moisture sensitivity of asphalt compounds containing two types of aggregates, i.e. limestone and siliceous. For this aim, the Sessile Drop Method (SDM) was employed, and moisture resistant parameters associated to surface free energy concept such as surface free energy components, work of cohesion, work of adhesion, work of debonding, adhesion bitumen to aggregate, and wetting bitumen around aggregate surface were assessed. The results revealed that the effect of the mixing time of bitumen and epoxy resin on moisture resistance properties of asphalt compounds significantly depends on the percentage of epoxy resin used in bitumen mixture. For bitumens with 4 and 6% epoxy resin, adhesion and wetting parameters had a similar performance for both mixing times of 10 and 60 minutes. However, asphalt compounds containing 2 and 8% epoxy resin modified bitumens prepared for 10 min mixing time had a better adhesion and wetting performance than those prepared for the longer mixing time, 60 minutes. The effect of mixing time of bitumen modified with epoxy resin on the bitumen and asphalt compound’ performance depend on the percent of additive in the bitumen.

Surface Wettability Of Boron And Oil-Treated Wood

Background: Nowadays, demands for more environmentally friendly and cost-effective preservatives are increasing, and new non-traditional procedures are being explored in wood protection field. Plant oils improve the dimensional stability, water repellency and equilibrium moisture content of wood, and protect wood against decay fungi by means of its hydrophobic properties. The aim of this study is to investigate the influence of heat treatment and oil impregnation with or without prior treatment with boron compounds on wetting characteristic of Scots pine ( Pinus sylvestris L.) and beech ( Fagus orientalis L.) wood. Wood specimens were impregnated with boric acid, borax and agricultural boron at concentrations of 1%, 2% and 5% followed by oil heat treated with waste and sunflower oil at 160ºC. Wettability was measured by contact angle with the sessile drop technique using water. Results: Water contact angles on oil treated specimens increased while wetting tension decreased, and the wood more poorly wetted by water compared to the controls. A change in the drop volume on the surface of double treated specimens was around 5% based on the initial drop volume. Waste oil treatment resulted in having the greatest water repellent efficiency. High loadings of boron compounds decreased the contact angle and therefore the quantity of water absorbed by the wood increased. Conclusion: Wettability was decreased in specimens pretreated with boron and this confirmed that the hydrophobic surface was created by oil. Wettability is a prerequisite for good adhesion, coating and painting and this feature may be reduced by the less hydrophilic surfaces created after oil heat treatment.

A physicochemical study of a modified sol–gel derived neodymium-hydroxyapatite

Nd-doped hydroxyapatite (HANd) nanoparticles, Ca10−xNdx(PO4)6(OH)2, x = 0.1, 0.2, 0.3, 0.4 and 0.5, were obtained via the sol–gel technique. The as-prepared powders were subsequently calcined at 600 and 700 °C. X-ray diffraction (XRD) was used to investigate phase purity, crystal structure while Fourier Transform Infrared Spectroscopy (FTIR) was used to analyze the functional group of the obtained powders. The unit cell constants have also been calculated and match well with those of the hexagonal hydroxyapatite with the space group P63/m. Powders calcined at 700 °C were better crystallized than at 600 °C, which was furthermore confirmed by the IR spectra. Moreover, wettability was measured using a static sessile drop technique. All powders have shown a high hydrophilicity.

Effect of applied voltage on wetting and corrosion of corundum refractory by CaO–SiO2–MgO molten slag

The wetting and corrosion behavior of the corundum substrate anode by CaO–SiO2–MgO molten slag was investigated via the joint application of the sessile drop method with applied voltage and SEM-EDS technique. The slag drop exhibited a good wettability on the corundum substrate. The apparent contact angle at zero voltage slightly exceeded that at a 1 V applied voltage but was lower than those at 1.5 V and 2 V ones. Low applied voltage of 1 V had little effect on the corundum substrate's direct dissolution corrosion processes; high ones of not less than 1.5 V caused the electrode reaction to occur. The stirring effect of O2 bubbles from the anode reaction aggravated the substrate's direct dissolution and physical stripping. It was found that the applied voltage could inhibit the slag penetration, and the apparent contact angle had no obvious relation with the direct dissolution thickness and penetration depth. A thin but almost continuous MgO⋅Al2O3 (MA) layer could form at the slag/substrate interface at the applied voltage of 1.5 V. These results indicate the positive effect of applied voltage on the distribution of interfacial products and the molten slag penetration in reducing the corrosion of corundum anode under certain conditions. However, when the applied voltage was too high, the vigorous electrode reaction could aggravate the direct dissolution and physical stripping of the corundum anode, and damage the continuation of the formed interface product layer with a high melting point.

Evaluation of polyphenylene sulfide by surface thermodynamics approaches: Comparison with common polymers

AbstractPoly(phenylene sulfide) (PPS) is an advanced thermoplastic and widely used in industrial applications requiring high performance. Research on improving the surface properties of PPS is still ongoing and a detailed surface free energy (SFE) knowledge of this polymer is necessary for its applications related to surface wettability. In this study, wettability characteristics of PPS were evaluated by SFE calculations. For this purpose, the apparent contact angles of nine different test liquids having various surface tensions were measured on the PPS surface by the sessile drop method. After that, the dispersive and polar components of SFE were calculated using geometric (Owens and Wendt's method) and harmonic (Wu's method) mean approaches. The Lifshitz‐van der Waals, acidic and basic components of SFE were calculated using van Oss‐Chaudhury‐Good method. Additionally, the surface tension values of PPS were also determined by equation of state, Zisman's critical surface tension and Fowkes' approaches. In the present study, the effects of calculation methods and selected liquid pairs on SFE parameters were systematically investigated. It was found that selected liquid pairs and calculation methods affected the SFE considerably. The reasons for this were examined and the SFE components of PPS was compared with some common polymers for better evaluation.

Epoxyorganosilane Finishing Compositions for Fibrous Fillers of Thermosetting and Thermoplastic Binders.

The development of universal finishing compositions for fibers of various natures is an urgent task for polymer composite materials science. The developed finishes can be used for the fiber reinforcement of polymer matrices with a wide range of surface free energy characteristics. Epoxy systems modified with diaminesilane in a wide concentration range were examined by optical interferometry, FTIR spectroscopy, DSC and the sessile drop technique. It was shown that the partial curing of epoxy resin by diaminesilane at room temperature under an inert atmosphere, followed by contact with air, leads to a significant increase of the surface free energy of the system. Varying the concentration of diaminesilane allows us to effectively regulate the surface free energy of the composition. This makes it possible to use fibers finished with epoxyaminosilane compositions in composite materials based on a various thermosetting and thermoplastic binders with a surface tension of up to 75 mJ/m2.