Improvement Of Wettability Research Articles

Influence of Plasma Treatment on Surface Characteristics of Aluminum Alloy Sheets and Bonding Performance of Glass Fiber-Reinforced Thermoplastic/Al Composites.

This study focuses on modifying the surface of an AA 5052-H32 aluminum alloy using plasma treatment. Discharge power, exposure time, and working gas were adjusted as process parameters to improve the adhesion between the aluminum alloy and glass fiber-reinforced thermoplastic (GFRTP) polycarbonate composite. The surface composition and morphology of the aluminum alloy sheet were analyzed by X-ray photoelectron spectroscopy and scanning electron microscopy, and surface roughness and wettability were evaluated using a surface roughness-measuring instrument and contact angle goniometry, respectively. The bonding performance of GFRTP/aluminum alloy was also assessed. The surface of the aluminum alloy was subjected to chemical treatment prior to plasma treatment. The results revealed that nitrogen plasma treatment led to a substantial increase (25%) in bonding strength due to the synergistic effect of rough surface mechanical bonding and chemical bonding through functional groups between the aluminum alloy and GFRTP. However, the improvement in surface wettability by plasma treatment is time dependent and may gradually diminish over time due to the re-adsorption of hydrocarbon contamination from the surrounding air.

Laser cladding of HA-TiO2 composite coating on Mg-alloy: microstructural characterisation and wettability analysis

ABSTRACT In the present work, hydroxyapatite (HA)-50 wt.% TiO2 composite coating has been developed on Mg-alloy by laser cladding process using 400 W continuous wave fibre laser. A detailed microstructural characterisation has been done by using optical profilometry, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction techniques. The wettability analysis has been done by the sessile method using hank’s solution. The average roughness is 0.5 μm for the Mg-1% Ca alloy and 1.45 μm for laser-cladded surface. The microstructure analysis shows uniform deposition with the presence of porosities, particles and few cracks on the top surface of laser-cladded surface. The composition analysis shows the uniform and homogeneous distribution of Ca, Ti, P, and O on the laser-cladded surface. The phase analysis shows the presence α, β phase in Mg-1% Ca alloy and the presence of Ca2P2O7, Ca3(PO4)2, CaTiO3 and TiO2 (rutile) phases in the laser-cladded surface. There is an improvement in wettability of the laser-cladded surface as compared to as-received Mg alloy.

Effect of Cetyltrimethylammonium Bromide Additives on Etched Tunnel Formation of Aluminum Foils

In this study, cetyltrimethylammonium bromide (CTAB) additive was introduced to adjust the tunnel etching behavior of aluminum foil. The distribution and growth of etched tunnels in solutions with and without CTAB additive of various concentrations were thoroughly investigated. Compared to the etched tunnels obtained in solutions without CTAB, those obtained in solutions with 1 wt% CTAB had obviously improved distribution and increased length, resulting in an enhancement of the specific surface area. These effects can be attributed to the improvement of wettability between aluminum surface and solution, which is helpful to increase the contact area and facilitate the mass transfer within tunnels. This work exhibits a facile way to improve the tunnel etching behavior of aluminum foil, showing a potential engineering value in industrial production.

Atomistic investigation on interfacial properties of glass surfaces modeling plasma modification and the influence of wettability conditions on adhesion

The utilization of plasma technology is a hot research topic in the field of glasses surface treatment, as there are still many urgent problems to overcome so as to improve adhesion strength. The improvement of surface wettability plays a leading role in bonding glasses to other materials. In this study, wettability models of water nanodroplets interaction with glass surfaces mimicking plasma modification were conducted by molecular dynamics simulation. The physicochemical properties of the material surface and environmental conditions have an important influence on the wettability evolution of the modified glass surface. The relative concentration, mean square displacement, adhesion energy were used to quantify the effect of wettability conditions on water-silica systems. The simulation calculations indicated that functional groups had a positive impact on the wettability improvement of glasses. As the density of functional groups on the glass surface increased, the surface wettability was significantly improved to form a dense water film on the surface. Increasing the roughness of the modified glass surface weakened its adhesion strength. Ambient temperature and moisture had little effect on surface wettability, while the evaporation of water molecules enhanced with the increase of temperature. These findings provide an insight into the wettability mechanism and vital information for improving the interface performance of plasma-modified glass surfaces.

Study of Argon and Oxygen Mixtures in Low Temperature Plasma for Improving PLA Film Wettability

Oxygen (O2) and argon (Ar) plasma give a significant improvement in the wettability of PLA films. This study investigates the effectiveness of plasma activation with a mixture of these two gases. The study includes contact angle measurements with water and diiodomethane and calculation of surface free energy (SFE) together with its polar and dispersion components. In addition, a chemical analysis of the surface, surface roughness, weight loss and the change in tensile strength were examined. As a result of the study, it was found that the use of a mixture of oxygen and argon during the plasma activation of the polylactide film gives better improvement in wettability than the use of pure gases. Moreover, the use of a mixture of these gases in equal proportions turned out to be the most effective, providing the highest value of the SFE and its polar component, as well as the lowest value of the water contact angle. Furthermore, plasma activation with this gas mixture results in reduced surface etching compared to other gas compositions, which manifests itself in lower weight reduction and an insignificant change in tensile strength.

High-performance thermoplastic polyaryletherketone/carbon fiber composites: Comparison of plasma, carbon nanotubes/graphene nano-anchoring, surface oxidation techniques for enhanced interface adhesion and properties

This investigation highlights the development and performance comparison of carbon fiber (CF)-polyaryletherketone (PAEK) thermoplastic laminates prepared using CF, surface-modified with plasma, multi-walled carbon nanotubes (MWCNT), graphene, acid, and rare earth elements. Analysis of surface-treated CF by Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) revealed development of functional groups and changes in elemental composition on the CF surface. Significant lowering of contact angle and improvement in wettability was achieved by plasma and MWCNT/graphene treatment on CF. Field emission scanning electron microscopy (FESEM) analysis gave insight into the surface irregularities caused by various surface treatment techniques. The CF-PAEK composites were prepared by film stacking and compression moulding. The plasma-treated PAEK-CF composites exhibited the highest tensile properties, flexural strength, fracture toughness, and interlaminar shear strength. The superior properties are credited to better interfacial adhesion between CF and PAEK arising from mechanical interlocking over the roughened surface and covalent bonds by functional groups grafted on CF surface by plasma. MWCNT and graphene-anchored CF-PAEK composites also showed significant improvement in mechanical properties attributed to the bridging effect and interfacial interaction arising from increased surface area and functional groups. The surface-treated CF-PAEK composites exhibited a positive shift in the glass transition temperature, which is evidence of better adhesion. In dynamic loading conditions, MWCNT anchored CF-PAEK composite presented the highest storage modulus and energy absorption characteristics. Examination of the tensile fracture surface and fiber pull-out gave insight into the failure pattern and interfacial adhesion mechanism for the individual surface modification techniques.

Polyphenolic compounds affect the long-term degradation behaviour of polymer and composite materials based on PCL, PLGA, and bioactive glass

In recent years, the modification of biodegradable aliphatic polyesters with bioactive ceramics and plant-derived active agents has gained much attention in biomedical applications. They provide significant improvement in biological functionality of synthetic polymers. However, they simultaneously affect numerous physicochemical properties. In this work, for the first time, effect of incorporation of polyphenols (PPh) extracted from sage and sol-gel-derived bioactive glass (BG) particles, either alone or in combination, into poly(ε-caprolactone) (PCL) and poly(lactic-co-glycolide) (PLGA) was evaluated. BG particles were shown to accelerate degradation of materials based on slowly degrading polymer - PCL, while degradation of materials based on fast degrading polymer – PLGA was retarded. For PLGA-based composites, the formation of apatite layer and dissolution of alkaline ions from BG appear to have pivotal role in controlling degradation by providing protection from direct exposition to aqueous environment and neutralizing acidic by-products. PPh were shown to accelerate degradation of all studied materials. The following PPh-related factors can be involved in this process: wettability improvement, acid catalysis, plasticizing effect, and porosity formation. Our results highlighted the importance of considering the effect of commonly used polymeric modifiers on one of the most important properties of biomaterials used in tissue engineering and drug delivery - degradation.

Wettability Improvement of a Carbazole-Based Hole-Selective Monolayer for Reproducible Perovskite Solar Cells

The wettability issue associated with the Me-4PACz hole-selective monolayer is solved by the introduction of the second component to the precursor solution. This results in a similar performance while simultaneously significantly improving the yield of the devices.

Investigation of surface structure-wettability coupling on heat transfer and flow characteristics in nanochannels

• The effect of surface wettability and roughness coupling is investigated by MD. • The progressively subdivided rough nanostructures are established. • The effect of wettability becomes slight when the scaling parameter exceeds 1.0. • The enhanced solid-fluid interaction energy reveals the microcosmic mechanism. The high integration of electronic devices has become an irresistible trend, what bottlenecks its development is the heat dissipation in micro/nanoscale. Surface roughness and wettability are the two main factors affecting convective heat transfer in nanochannels. However, the combined effects of wettability and roughness are still unclear. Consequently, by molecular dynamics simulation, the combined impact of wettability and roughness on heat transfer and flow characteristics are investigated in rectangular nanochannels with various wettability and progressively subdivided roughness. The results show, when the surface becomes more hydrophilic and subdivided, the temperature and Nu increase, whereas the temperature slip decreases, leading to an efficient improvement of the heat transfer process. Moreover, the velocity slip decreases, and the flow resistance increases, so the fluid flow process is relatively inhibited. Particularly, the effects of wettability and roughness are inconsonant. For the cases in this research, when the wettability scaling parameter exceeds 1.0, the hindrance of wettability to velocity development becomes slight. However, the improvement of wettability to temperature development is still significant. Microscopically, it’s found more atoms accumulate at the solid-liquid interface, and solid-liquid interaction energy enhances. This investigation provides theoretical guidance for the efficient cooling of micro/nano electronic devices.

Enhanced abrasive-mixed-µ-EDM performance towards improved surface characteristics of biodegradable Mg AZ31B alloy

The non-degradable metallic implants, such as bone screws, often act as the source of dysfunction and harmful corrosion products in the aqueous environment inside the human body. Many of these implants are fixed either temporarily or permanently into the human body, and therefore, both need to match tight tolerances with a remarkably finished surface to eradicate burrs or striations. In this regard, the new generation of degradable magnesium (Mg) alloy implants with excellent osseointegration and low elasticity (like that of human bone), minimizing stress shielding, have been identified as potential candidates to challenge surgical procedures reintervention. However, the biological response of an implant toward the cells in vivo can be predominantly regulated by modifying the surface chemistry, morphology, and corrosion characteristics. Powder or abrasive-mixed-micro-electric discharge machining (A-M-µ-EDM) is gaining attention for executing precision machining and achieving a simultaneous surface modification on micro-manufactured surfaces, suitable for clinical applications. Therefore, the present research aimed at improving the surface characteristics of Mg AZ31B alloy via an augmented performance of A-M-µ-EDM by adopting copper and brass-micro-electrodes (C-µ-E and B-µ-E) in association with distinct abrasive particle concentrations (APCs: 0, 1.5, 3, 4.5, and 6g/l) of bioactive zinc abrasives. To enhance the A-M-µ-EDM capabilities, the experiments were designed with a one-variable-at-a-time (OVAT) strategy, and the trial runs were conducted using different combinations of µ-electrodes and APCs. The superior performance of A-M-µ-EDM was noticed with the fusion of C-µ-E and 3g/l APC in terms of minimum machining time (MT) and dimensional deviation (DD). The additional outcomes of this work reported favorable improvements in surface morphology, chemistry, topography, wettability, microhardness, and corrosion resistance on the A-M-µ-EDMed sample of interest.

Cost-effective equipment for surface pre-treatment for cleaning and excitation of substrates in semiconductor technology

This article presents a cost-effective ultraviolet-ozone cleaner (UV/O3 Cleaner) for surface pre-treatment of substrates in the field of semiconductor technology. The cleaner consists of two chambers, the upper one contains the electronics, including the time counter. The lower chamber contains the two UV sterilisation lamps and a UV reflector of anodized aluminium, which confines the area of high Ozone concentration in the area of interest. The device is successfully used for surface cleaning and modification of different materials. To this end, the two important wavelengths 253.7 nm (excitation of organic residues) and 184.9 nm (production of ozone from the atmospheric environment as a strong oxidant) were first detected. The effectiveness of UV/O3 cleaning is demonstrated by improving the properties of indium tin oxide (ITO) for OLED fabrication. The contact angle of water to ITO could be reduced from 90° to 3° and for diiodomethane, it was reduced from 55° to 31° within the 10 min of irradiation. This greatly improved wettability for polar and non-polar liquids can increase the flexibility in further process control. In addition, an improvement in wettability is characterized by measuring the contact angles for titanium dioxide (TiO2) and polydimethylsiloxane (PDMS). The contact angle of water to TiO2 decreased from 70° to 10°, and that of diiodomethane to TiO2 from 54° to 31°. The wettability of PDMS was also greatly increased. Here, the contact angle of water was reduced from 109° to 24° and the contact angle to diiodomethane from 89° to 49°.Article HighlightsWe report a cost-effective dry-cleaning device for surface cleaning and modification based on ultraviolet-ozone irradiation.Contact angle measurements show an increase of wettability for different materials due to surface modification.The UVO3 pre-treatment improves layer formation and optoelectrical properties of OLEDs.

Effect of electrochemical oxidation degree of carbon fiber on the interfacial properties of carbon fiber–reinforced polyaryletherketone composites

Electrochemical oxidation of carbon fiber (CF) is used to enhance the interfacial adhesion of CF-reinforced polyaryletherketone (CF/PAEK) composites. The effect of current intensity parameter on surface structure of CF and interfacial properties of the corresponding thermoplastic composites are deeply investigated. The results show that the current intensity in the range of 80 A–300 A does not lead to a decrease in the mechanical property of CFs. When the current intensity is 200 A, CF/PAEK composites have the highest interfacial performance, which is mainly due to the improvement of CF surface roughness, wettability, and oxygen content. In addition, the degree of graphitization of CF surface is also a crucial factor affecting the interfacial properties of CF/PAEK. The higher the content of carboxyl groups, the more disordered the structures exist on the CF surface, which are not conducive to the strong adhesion of CF to PAEK resin. Therefore, balancing the wettability and graphitization degree of the CF surface is the key to enhancing the CF/PAEK interfacial properties by electrochemical treatment techniques.

Heat treatment induced strength improvement of the injection-molded joint between polymer and blasted steel

Blasting treatment faces the problem of insufficient joining strength when it is applied to metal-polymer direct joining via injection molding. In this study, a secondary heat treatment was proposed to improve the joining strength of abrasive-blasted steel and polymer joints. After the heat treatment, flower-like nanostructures were produced on the steel surface and the surface roughness Sa increased from 112.9 nm to 145.0 nm, providing more space for molten polymer to flow into. The surface free energy of steel surface increased to 76.2 mN/m after the heat treatment, indicating the improvement of steel surface wettability and less resistance for polymer infiltration. The joining strength increased by 45 % and reached 24.5 MPa via the heat treatment. Through fracture surface observation, the occurrence of cohesive failure further confirmed that the heat treatment effectively improved the mechanical interlocking at the joining interface.

Enabling an electron/ion conductive composite lithium anode for solid-state lithium-metal batteries with garnet electrolyte

• A composite lithium anode with continuous electron/ion dual-conductive networks is engineered on the surface of garnet-type ceramic electrolyte. • The solid-state Li-symmetric cells exhibit a low interfacial resistance of <2.0 Ω cm 2 , a high critical current density of 1.1 mA cm −2 and a long lifespan of >3500 h. • The LiFePO4-based solid-state batteries can deliver high specific capacity of 161.7 mAh g −1 at 25 °C, with good cycle and rate performance. The use of Li anode is critical for the energy density of solid-state Li-metal batteries (SSLMBs) to surpass that of lithium-ion batteries. However, the practical applications are hampered by the large interfacial resistance and poor physical contact at the solid-state interface, as well as dendrite issues and volume changes of Li anode. Here, a composite lithium anode with continuous electron/ion conductive networks is fabricated, which shows a significant improvement in wettability towards garnet-type Li6.4La3Zr1.4Ta0.6O12 electrolytes. The intimate interface and its high charge-transfer kinetics of composite Li anode endows the symmetric cell a small overpotential (45 mV) at 0.3 cm −2 , ultra-low interfacial resistance (∼ 2.0 Ω cm 2 ), high critical current density (1.1 mA cm −2 ), and outstanding cycling performance (>3000 hours at 0.1 mA cm −2 ) at 25 °C. The SSLMB paired with LiFePO 4 delivers a high discharge specific capacity of 161.7 mAh g −1 at 0.1 C, good cycle performance of 100 cycles with capacity retention of 80%. Moreover, the NMC811-based SSLMB can also realize a high capacity of 219.5 mAh g −1 , superior rate capability and cyclic stability. This work lays the foundation to develop composite Li anodes for practical applications of SSLMBs with high performance.

Laboratory Investigation of Nanofluid-Assisted Polymer Flooding in Carbonate Reservoirs

In the petroleum industry, the remaining oil is often extracted using conventional chemical enhanced oil recovery (EOR) techniques, such as polymer flooding. Nanoparticles have also greatly aided EOR, with benefits like wettability alteration and improvements in fluid properties that lead to better oil mobility. However, silica nanoparticles combined with polymers like hydrolyzed polyacrylamide (HPAM) improve polymer flooding performance with better mobility control. The oil displacement and the interaction between the rock and polymer solution are both influenced by this hybrid approach. In this study, we investigated the effectiveness of the injection of nanofluid-polymer as an EOR approach. It has been observed that nanoparticles can change rock wettability, increase polymer viscosity, and decrease polymer retention in carbonate rock. The optimum concentrations for hydrolyzed polyacrylamide (2000 ppm) and 0.1 wt% (1000 ppm) silica nanoparticles were determined through rheology experiments and contact angle measurements. The results of the contact angle measurements revealed that 0.1 wt% silica nanofluid alters the contact angle by 45.6°. The nano-silica/polymer solution resulted in a higher viscosity than the pure polymer solution as measured by rheology experiments. A series of flooding experiments were conducted on oil-wet carbonate core samples in tertiary recovery mode. The maximum incremental oil recovery of 26.88% was obtained by injecting silica nanofluid followed by a nanofluid-assisted polymer solution as an EOR technique. The application of this research will provide new opportunities for hybrid EOR techniques in maximizing oil production from depleted high-temperature and high-salinity carbonate reservoirs.

Effect of Viscosity and Surface Roughness on Improvement of Solid-liquid Wettability by Ultrasonic Vibration

Effect of Viscosity and Surface Roughness on Improvement of Solid-liquid Wettability by Ultrasonic Vibration

Improvement of Soft Contact Lens Wettability After the Instillation of Hyaluronic Acid Eye Drops.

To evaluate the effect of the topical instillation of hyaluronic acid eye drops with different viscosity on soft contact lens wettability and comfort. A randomized and participant-masked study was performed, involving 20 participants (25.4±2.6 years). One eye wore hydrogel (ocufilcon D) contact lenses, and another eye wore silicone-hydrogel (somofilcon A) contact lenses. The in vivo wettability tear film surface quality (TFSQ) index and comfort were measured before and after the instillation of different eye drops: saline solution (control) and 0.1%, 0.2%, and 0.3% hyaluronic acid. Compared with saline solution, the instillation of 0.1%, 0.2%, and 0.3% hyaluronic acid improved the in vivo wettability of the hydrogel contact lenses by decreasing their TFSQ mean for 5, 10, and 30 min, respectively ( P <0.05). During silicone-hydrogel contact lens wear, the hyaluronic acid did not affect wettability because there were no changes in TFSQ mean ( P ≥0.05), but the 0.3% hyaluronic acid produced a decrease in comfort for the first 3 min ( P <0.05). The instillation of hyaluronic acid eye drops increased the in vivo wettability of the hydrogel contact lens, and the duration of this effect was directly related to its concentration and viscosity.

The equilibrium contact angle of ammonia-stainless steel interface

The knowledge of the wettability at the interface of different liquids and solid surfaces must be replenished in steps with material science. Wettability is a critical property in technologies where the interaction of fluid and solid substances is part of the working processes. This paper provides a brief experimental study dealing with the equilibrium contact angle identification at the interface of ammonia and stainless steel plates (SS316L) at different temperatures. The method with the capillary rise at the vertical plate has been exploited and validated with the available water/SS316L test data. The contact angles in the range 10° … 27° have been identified for the temperature range [-11 … 75] 0C with the apparent justification of wettability improvement with an increase in fluid temperature.

(NH4)2S-induced improvement of interfacial wettability for high-quality heterojunctions to boost the chloride-assembled CZTSSe solar cells.

Concernin the crucial interfacial issues in multi-layered kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells, (NH4)2S treatment has been proven to be effective in eliminating surface secondary phases. While for the CZTSSe absorbers without impurity phases, what can the low-temperature (NH4)2S treatment do to the absorbers, thus to the device performance? Herein, the chloride-fabricated CZTSSe absorbers are surface treated with the (NH4)2S solution at room temperature, and its influence on the device performance is investigated in detail. Surprisingly, such treatment can make the absorbers' surface become nearly super-hydrophilicity, greatly decreasing the surface wetting angle from 63.1° ± 3.4° to 7.3° ± 0.6° after 50 min-treating, and thus lead to marked differences in the interfacial properties of the CdS/CZTSSe heterojunctions deposited in a chemical bath. Consequently, for the best-performing CZTSSe cells, combining the passivated interfacial defects, increased carrier concentration, reduced carrier recombination, and prolonged minority lifetime, the efficiency is improved from 6.54% to 9.88%, together with the 37 mV and 7.9% increase in VOC and FF, respectively. This study confirms the newfound results that the (NH4)2S treatment can effectively adjust the wettability of the absorbers to form high-quality heterojunctions to boost the device efficiency, which would be valuable for an in-depth understanding of the intrinsic mechanisms of interfacial processing.

Wettability and thermal contact resistance of thermal interface material composited by gallium-based liquid metal on copper foam

As a promising thermal interface material (TIM), gallium-based liquid metal (GBLM) could significantly reduce the thermal contact resistance (TCR) at the solid-solid interfaces, while the leakage of GBLM and the wettability between liquid metal and solid surface restrict further application. In this study, the GBLM was wrapped with a copper foam (CF) skeleton, which prevents leakage and improves the thermal conductivity of the GBLM. Gallium-based liquid metal-copper foam (GBLM-CF) TIM was prepared by the self-wetting of the CF surface through the galvanic corrosion of GBLM. As the concentration of HCl increases from 0 to 5 M, the interfacial tension (IFT) in the HCl solution decreases from 536.80±1.00 mN/m to 481.52±0.49 mN/m, demonstrating that the IFT of the GBLM is inversely proportional to the concentration of HCl. Meanwhile, the decrease of contact angle (CA) by 8° indicates that the presence of CuGa2 on the surface promotes the wettability of GBLM. With the increase of external pressure and the improvement of wettability, the TCR between the GBLM and the copper sheet decreased by 58.28%. The TCR of the sample using GBLM-CF as TIM is 83% lower than that of thermal grease. Moreover, the thermal conductivity of GBLM-CF TIM (51.58±0.01 W/(m·K)) is 212.6% higher than that of GBLM (16.50±0.02 W/(mK)). The GBLM-CF TIM presented in this study can be used for the efficient thermal management of electronic equipment.