Optimal Contact Angle Research Articles

Micro/Nano Hierarchical Crater-Like Structure Surface With Mechanical Durability and Low-Adhesion for Anti-Icing/Deicing.

Superhydrophobic surfaces have attracted significant attention for their ability to prevent ice formation and facilitate deicing without requiring external energy. However, these surfaces are often vulnerable to damage from external forces, leading to functional failure due to poor mechanical stability, which limits their widespread use. Drawing inspiration from the hierarchical groove of rose petals and the micropapillae of lotus leaves, a simple laser-based method is proposed to create a superhydrophobic surface with a micro/nano hierarchical crater-like structure (HCLS). To enhance the surface, boiling water treatment is applied to induce dense nanostructures, resulting in an optimal contact angle (CA) of 162° and a desirable sliding angle (SA) of 2.0°. The initial ice adhesion strength of HCLS is as low as 1.4kPa and remains below 10kPa even after 300cm sandpaper abrasion. Furthermore, the HCLS demonstrates excellent mechanical durability, maintaining its performance under conditions that simulate the continuous impact of water and sand in extreme weather. This approach offers an innovative design concept that has the potential to advance the development of anti-icing and deicing surfaces for future aircraft.

Dynamic wetting characteristics of two droplets impacting a spherical dust particle

The removal of dust based on water misting is one of the most effective measures for dust control, and the basis of this method lies in the liquid–solid impact behavior. To further improve the dust removal efficiency, in this work, the removal mechanism was studied at the microscopic level, and the dynamic impact between two water droplets and a spherical dust particle was simulated using the coupled level-set/volume-of-fluid (CLSVOF) method. The optimal parameter ranges for micron-level dust removal were determined through the method of variable control, and the reliability of the obtained results was experimentally verified. When two droplets continuously or simultaneously impact a spherical particle, the liquid film formed undergoes deformation phenomena such as fusion, rupture, stretching, contraction, and fragmentation. The liquid film is more likely to break at higher droplet velocities, leading to the filling of the gas film and hindering the wetting process. The optimum contact angle and velocity range of the liquid droplets to completely encapsulate the dust particles were found to be θ = 2 and V = 10–20 m/s, respectively. The experimental results also showed that for the same dust particle size, the dust removal efficiency initially increased but then decreased with increasing dust concentration. The optimum dust removal efficiency of 98.1 % was achieved for θ = 2 and V = 10 m/s. This study sheds new light on the dust removal mechanism of water mist-based dust removal technologies and can aid in the design and parameter optimization of more effective dust suppression systems.

Modified silica nanoparticles stabilized foam for enhanced oil recovery

Foam has been successfully used to improve mobility control in the process of enhanced oil recovery, yet the instability of foam limits its application. Modified nanoparticles with varying wettability were prepared by reacting 3-methacryloxypropyltrimethoxysilane (KH570) with spherical SiO2 nanoparticles in this study. Fourier transform infrared (FTIR) spectra and the measured contact angles were used to characterize the surface properties of the modified SiO2 particles, and the foam stabilization effects of wettability SiO2 were compared. Pore-scale visualization experiments were conducted using a 2D micromodel to identify the prevailing enhanced oil recovery (EOR) mechanisms of modified nano SiO2-Sodium alpha-olefin Sulfonate (AOS) foam flooding. The results indicate that modified SiO2 effectively improves foam stability by adsorbing on the bubble surface and forming a mesh-like structure. The optimum contact angle of the particles is approximately 60°, resulting in a significant increase in drainage half-life by 29.4% compared to foam stabilized only by AOS. Additionally, Foam stabilized by modified SiO2 demonstrates superior dynamic stability and deformation resistance. The modified SiO2 stabilized foam exhibits enhanced interfacial viscoelasticity and plugging and profile control performance, surpassing AOS foam in displacing more residual oil in dead-end pores. The oil recovery of the micro model was determined by ImageJ software. KH570@SiO2 (0.2wt%)-AOS (0.2wt%) foam flooding increased the recovery by 8.7% compared to AOS (0.2wt%) foam flooding.

Effect of Femtosecond‐Laser‐Induced Surface Textures on the Microstructure and Mechanical Properties of Mg/Ti Dissimilar Alloys Laser Lap Welds: A Numerical and Experimental Study

The strength of the joints in the Mg/Ti laser welding is difficult to meet the requirement because of the metallurgical incompatibility. This study investigates the influence of microgroove width on the diffusion of molten Mg and the mechanical properties of joints by laser welding Ti6Al4V and AZ31B, employing femtosecond lasers to fabricate microgrooves on the surface of Ti alloys. The optimal contact angle of 56.4° is achieved at the microgroove width of 100 μm because the leading and trailing edges of the microgroove texture can stimulate the formation of the microriveted structure, facilitating the fluidity of the liquid AZ31B. The joint's tensile–shear capability is increased to 2449.9 N, which is 2.8 times stronger compared to joints without microgroove textures, when using a microgroove width of 100 μm and a laser power of 52%. The numerical simulation of the laser welding process was implemented to analyze the temperature field and the fluid characteristics within the melt pool. In the results, it is shown that the microgroove enhanced the material exchange at the interface and accelerated the interfacial reaction, which stimulates the formation of Ti–Al and Mg–Al intermetallic compounds at the central interface of the joint and enhances the Mg/Ti metallurgical bonding.

Parameters optimization for decontamination and fine physical regeneration pathways of polypropylene plastics from waste lunchboxes

Due to the development of the food delivery industry, a large amount of waste lunchboxes made of homo polypropylene (PP) plastic have been generated. This study developed a new technological strategy to effectively regenerate PP from waste lunchboxes. Through response surface curve analysis, it was found that under the optimal process conditions of hot alkali washing at 80 ℃, 30 min, and pH 13, the optimal contact angle was 65.55°, indicating a good oil stain removal effect. By identifying and analyzing the characteristics of impurities in waste lunchboxes, a physical sorting and granulation regeneration process was constructed. And through large-scale statistical analysis and data collection, it was further verified that recycled PP plastics maintained their physical stability and excellent processing performance. The quality stability of recycled PP plastics in terms of impurities content was also verified. By designing different formulations specifically, recycled PP was mixed with different virgin PP and antioxidants in appropriate proportions, and extruded into particles under 150–300 mesh filtration conditions to obtain modified recycled PP. Modified recycled PP was applied in textiles, clothing, and injection molded products. In conclusion, we achieve the up-cylcing of waste PP lunchboxes instead of down-cylcing.

Stabilization of Pickering emulsions by oxidized starch/zein nanoparticle complexes

In this study, oxidized starch (OS)/zein nanoparticles (ZNP) complexes were prepared and used to stabilize Pickering emulsions. The effect of starch oxidation using three levels of sodium hypochlorite (2.0%, 3.0%, 4.0% active chlorine, dry basis) on the properties of OS/ZNP complexes and complex-stabilized Pickering emulsions were evaluated. The interaction between oxidized starch and zein nanoparticles was confirmed by X-ray diffractometry (XRD) and Fourier transform infrared (FT-IR) spectrometry. The presence of oxidized starch improved the wettability of OS/ZNP complexes. The optimum contact angle (θ) of OS/ZNP complexes was 90.88°, when starch was oxidized with 3.0% active chlorine (3.0% OS). The appearance, micromorphology and oil droplet-size distribution suggested that OS/ZNP complex-stabilized Pickering emulsions were formed. Rheological measurements indicated that Pickering emulsions showed shear-thinning behavior. Furthermore, the viscoelasticity of Pickering emulsions was dependent on the oxidized starch and oil fractions. Stability test showed that the stability of Pickering emulsion can be improved by increasing the oil fraction from 20% to 50%, and Pickering emulsion stabilized by 3.0% OS/ZNP complexes had the highest stability. This work provides information on OS/ZNP complex-stabilized Pickering emulsions.

Experimental investigation of the sequence injection effect of sea water and smart water into an offshore carbonate reservoir for enhanced oil recovery

This study explores enhanced oil recovery (EOR) strategies, with a focus on carbonate reservoirs constituting over 60% of global oil discoveries. While “smart water” injection proves effective in EOR for carbonate reservoirs, offshore application challenges arise due to impractical volumes for injection. To address this, we propose a novel continuous injection approach, systematically investigating it on a laboratory scale using the Iranian offshore reservoir, Sivand. Thirty-six contact angle tests and twelve flooding experiments are meticulously conducted, with key ions, potassium, and sulfate, playing pivotal roles. Optimal wettability alteration is observed at 4 times potassium ion concentration in 0–2 times sulfate concentrations, driven by ionic strength and charge interactions. Conversely, at 3–5 times sulfate concentrations, the optimal contact angle shifts to 2 times potassium ion concentration, suggesting a mechanism change linked to increasing sulfate ion ionicity. A significant wettability alteration, evidenced by a 132.8° decrease, occurs in seawater with a twofold concentration of potassium ions and a fivefold concentration of sulfate ions. Micromodel experiments introduce an innovative alternation of smart water and seawater injections. The first scenario, smart water followed by seawater injection, reveals negligible post-seawater injection oil recovery changes. In contrast, the second scenario yields a maximum recovery of 7.9%. The first scenario, however, boasts superior overall sweep efficacy, reaching approximately 43%. This research expands understanding of smart water and seawater injection in EOR, presenting a viable solution for optimizing offshore carbonate reservoir recovery. The insights contribute to evolving EOR methodologies, emphasizing tailored strategies for varying reservoir conditions.

Analogous Charging Effect of Surfactant-Pesticide Spray Jet on Droplet Characteristics and Deposition on Hydrophobic Leaf Surfaces

An induction charging principle had been applied to enhance spray droplet characteristics and quantity deposition on hydrophobic abaxial-adaxial leaf surfaces from pesticide EC Glyphosate [C3H8NO5P] and surfactant Silwet L-77 [C13H34O4Si3] formulations. A nozzle cap containing two electrodes (spacing at 9 mm apart) was used to superpose charges to spray droplets under applied voltages of 2–12 kV in an electric field (E) of 8.9 × 105 V/m. From a tee-jet flat fan (TP11004VS) nozzle tip fitted into the electrode cap and positioned at 60 cm high above targeted Brassica campestris leave surfaces, the spray droplets were directed onto the leaves at a liquid flow pressure of 4 bar and travelling speed of 2 m/s. The measurements were done using Keithsley picoammeter to quantify spray chargeability (CMR), droplet sizes by lesser particle size analyzer (LPSA) and deposition on leaf surfaces by high-speed camera. In effect, droplet sizes of EC, L-77 and EC + L-77 decreased with an increasing applied voltage. The CMR of L-77 was lower than EC and highest for EC + L-77 composite solution. Based on Image analysis of droplets density per leaf area, maximum exposure of adaxial leaf surfaces intercepted many charged spray droplets than abaxial surfaces. As regressed, the quantity of charged spray deposition from EC + L-77 formulation was highest at both adaxial (approx. 27.44 Qd/cm2) and abaxial (approx. 5.57 Qd/cm2) hydrophobic leaf surfaces than EC of 26.12: 3.19 Qd/cm2 and L-77 of 24.80: 2.53 Qd/cm2, respectively. Also, contact angle, Theta E, of charged spray droplets was smaller than Theta C on adaxial than abaxial leave surfaces, a phenomenon attributed to high chemo-electrical properties of formulations that aided the direct flight, coiling and deposition of droplets in order of EC > EC + L-77 > L-77. Generally, there was no observable droplet rebound; hence, surfactant-pesticide composite spraying is considered suitable for electrostatic application in plant protection technology. Therefore, for effective application, charged droplets from glyphosate EC in silwet L-77 solution should be recommended, as it provides optimum droplet sizes, chargeability, contact angle and deposition on hydrophobic leave surfaces.

Hydrophobicity and mechanical properties of purified lignin nanoparticles reinforced marine‐derived biopolymer composites

AbstractLignin has been considered the main aromatic renewable biopolymer. Besides its availability in large quantities as a major and low‐cost side product of several industries as a polysaccharide component of lignocellulosic biomass for industrial applications, it remains underutilized and as such, lignin valorization is highly desirable. This study was focused on the fabrication, purification, and characterization of lignin nanoparticles (LNPs) from black liquor of oil palm (Elaeis guineensis) empty fruit bunch (EFB). The functional properties of the LNPs investigated include the morphology, particle size, zeta potential distribution, elemental composition, functional groups, and gas chromatography–mass spectrometry (GC–MS). The purified LNPs provided smaller particle sizes ranging from 32 to 62 nm while the unpurified sample sizes range between 53 and 88 nm. The zeta potential value of purified LNPs displays relatively good stability to the unpurified LNPs despite the consistency in their particle size spreading as observed from the TEM micrograph. The results of the GC–MS analysis signify that the purification procedure affects the compounds in the LNPs. The kappa‐carrageenan (KC) biopolymers reinforced with purified LNPs provided more organized surfaces than the biopolymers reinforced with unpurified LNPs, leading to enhanced hydrophobicity and mechanical properties of the bionanocomposites. This study shows the potential applications of valorized lignin from oil palm residue as a reinforcement agent in renewable packaging.Highlights Lignin nanoparticles (LNPs) were yielded from empty fruit bunch black liquor. Syringyl to guaiacyl ratio of LNPs was increased from 0.83 to 1.26. Biopolymers were prepared by incorporating LNPs into the kappa‐carrageenan. Biopolymer with 4% purified LNPs had an optimum contact angle of 106.83°. The optimized biopolymer showed an optimum tensile strength of 38.42 MPa.

Enhancing polytetrafluoroethylene (PTFE) coated film for food processing: Unveiling surface transformations through oxygenated plasma treatment and parameter optimization using response surface methodology.

Spray drying fruit juice powders poses challenges because sugars and organic acids with low molecular weight and a low glass transition temperature inherently cause stickiness. This study employed a hydrophobic polytetrafluoroethylene (PTFE) film to mimic the surface of the drying chamber wall. The Central Composite Design (CCD) using response surface methodology investigated the impact of power (X1, Watt) and the duration of oxygenated plasma treatment (X2, minutes) on substrate contact angle (°), reflecting surface hydrophobicity. To validate the approach, Morinda citrofolia (MC) juice, augmented with maltodextrins as drying agents, underwent spray drying on the improved PTFE-coated surface. The spray drying process for MC juice was performed at inlet air temperatures of 120, 140, and 160°C, along with Noni juice-to-maltodextrin solids ratios of 4.00, 1.00, and 0.25. The PTFE-coated borosilicate substrate, prepared at a radio frequency (RF) power of 90W for 15 minutes of treatment time, exhibited a porous and spongy microstructure, correlating with superior contact angle performance (171°) compared to untreated borosilicate glass. Optimization data indicated that the PTFE film attained an optimum contact angle of 146.0° with a specific combination of plasma RF operating power (X1 = 74 W) and treatment duration (X2 = 10.0 minutes). RAMAN spectroscopy indicated a structural analysis with an ID/IG ratio of 0.2, while Brunauer-Emmett-Teller (BET) surface area analysis suggested an average particle size of less than 100 nm for all coated films. The process significantly improved the powder's hygroscopicity, resistance to caking, and moisture content of maltodextrin-MC juice. Therefore, the discovery of this modification, which applies oxygen plasma treatment to PTFE-coated substrates, effectively enhances surface hydrophobicity, contact angle, porosity, roughness, and ultimately improves the efficacy and recovery of the spray drying process.

Wettability effect on displacement in disordered media under preferential flow conditions

Preferential flow in a porous medium is commonly encountered in many practical applications. Our previous studies have discovered the preferential flow-induced non-monotonic wettability effect on displacement (J. Fluid Mech, vol. 942, 2022a, R5), but whether this non-monotonic rule is consistent for different disordered media and the impact of the interplay between the disorder and wettability under preferential flow conditions is still not well understood. Here, we combine microfluidic experiments, pore-scale simulations and theoretical analysis to study the impact of the disorder on the invading process where wettability varies from strongly water wet to strongly oil wet. Even though the strongly disordered matrix varies to a uniform state, the generality of the preferential flow-induced non-monotonic wettability effect is still proved. However, the previous pore-scale dynamics based on the strongly disordered matrix cannot explain the invading behaviour in the uniform matrix under preferential flow conditions. New mechanisms for the uniform matrix are further investigated by pore-scale modelling, which indicates that the balance of microscopic imbibition ability and the macroscopic interfacial stability dominate the invading process. We derive a theoretical model to describe the wettability effect and predict the optimal contact angle, which fits well with experimental and simulation results. Our work extends the understanding of the impact of preferential flow conditions on the wettability effect and is also of practical significance for engineering applications, such as geological CO2 sequestration, enhanced hydrocarbon recovery, soil wetting, liquid-infused material fabrication and microfluidic device design.

The role of electrochemical interaction in the success of engineered water flooding

Engineered water flooding (EWF) is widely suggested as a successful EOR method that is economically feasible and environmentally friendly. The current study performed two sets of core-flooding tests on Indiana limestone by two different oil samples in a wide salinity range to understand the role of oil in the success of EWF. According to the results, oil A demonstrated an ascending oil recovery with brine dilution from seawater (SW) to 100-time diluted seawater (SW100D). However, oil B indicated a maximum oil recovery at SW10D. The experimental oil/brine interfacial tension (IFT) could not explain the oil recovery results for any oil sample. However, the counterpart contact angles showed that the rock-fluid mechanisms dominated the oil recovery behavior. For oil A, the rock tended to be more water-wet with brine dilution, which justifies the late breakthrough and more oil recovery for SW100D than other brines. For oil B, the optimum contact angle was observed at SW10D. This explains why the injection of SW10D increases the breakthrough time and the oil recovery rather than SW and SW100D. Rock/brine zeta potential decreased from −0.7 to −13.7 mV with salinity reduction of SW to SW100. The zeta potential of oil B/brine decreased (−7.9 to −61.1 mV) significantly more than oil A/brine (from −2.9 to −15.1 mV) with the same dilution. One can conclude that as salinity decreases, oil is repulsed by rock, and it creates a more water-wet surface, as occurred for oil A. This general view cannot explain the reason behind the optimum CA of oil B. Using the DLVO theory, the current study demonstrated that asymmetry (in absolute value, not only in sign) between the rock surface potential and oil decreases repulsion. Although oil B became more negative by diluting from SW10D to SW100D, the asymmetry increased the contact angle of SW100D rather than SW10D.

Waste heat recovery enhancement in the CO2 chemical absorption process by hydrophobic-hydrophilic composite ceramic membranes

A novel ceramic composite membrane configuration was proposed to improve the waste heat recovery performance from stripped gas in the CO2 chemical absorption process. Tubular hydrophobic and hydrophilic ceramic membranes were serially assembled to form a single composite membrane. The stripped gas and bypassed CO2-rich solvent flowed countercurrent on both sides of the composite membrane. The waste heat recovery performance from the stripped gas was investigated under eight membrane configurations using: hydrophobic, hydrophilic, and Janus membranes (i.e., with hydrophilic inner-surface and hydrophobic outer-surface, and viceversa). Results showed that when the stripped gas enters the hydrophobic segment, the waste heat recovery performance increases to a plateau and then decreases with an increasing length of the hydrophobic segment. When the length ratio of the hydrophobic segment was 25%, a maximum waste heat recovery performance was achieved. Similarly, an increase in the hydrophobicity of the hydrophobic segment caused an increase in waste heat recovery performance, in which the optimal water contact angle (CA) was 137.35°. As a result of the abovementioned conditions, a 7.44%–25.15% higher waste heat recovery of the composite membrane was achieved compared to commercial hydrophilic membranes.

Preparation of superhydrophobic coating with anti-corrosion and anti-fouling properties on the surface of low manganese steel by electrodeposition

As a rare earth slow-release agent, the yttrium (Y) element was often used in anti-corrosion coatings at high temperatures. Still, its application in anti-corrosion coatings at room temperature was rarely studied. Therefore, in this study, a stearic acid‑yttrium (SA–Y) superhydrophobic coating was prepared in one step on the surface of low manganese steel by electrodeposition. Different electroplating voltages were applied to the electrolyte composed of Y(NO3)3·6H2O and stearic acid (SA), and the effect of the voltage on the surface morphology and wettability of the coating were studied. The results show that the optimum water contact angle of SA–Y superhydrophobic coating is about 162.1 ± 1.2°, and the corrosion current density of the coating (8.68 × 10−10 A/cm2) is four orders of magnitude lower than that of the low-manganese steel sample (1.22 × 10−6 A/cm2), which confirmed that the coating has good corrosion resistance. At the same time, the soil powders cannot adhere to the surface of SA–Y superhydrophobic coating, indicating that the coating also has good anti-fouling properties. And studies have shown that during the corrosion process, a dense protective layer can be formed on the damaged coating surface to prevent further corrosion of the metal, so the coating has good active protection ability. Therefore, the coating prepared in this study has a good application prospect in the field of ship anti-corrosion.

Effect of modified montmorillonite particles on generation of in-situ W/O emulsion and oil displacement mechanism in enhanced heavy oil recovery

Water-in-oil (W/O) emulsions can enhance the sweep efficiency and control the mobility ratio of oil and water simultaneously in heavy oil development. However, the W/O emulsions formed by heavy oils and injected fluids are prone to be with low phase inversion point and low maximum internal phase volume, which leads to serious tonguing and fingering especially in heterogeneous reservoirs. The authors thus proposed a new method of stabilizing W/O emulsions with modified montmorillonite particles (MMPs) to increase the phase inversion point as well as the internal phase volume to enable economically viable recovery of heavy oils. This paper evaluated the emulsions injected with different types of MMPs in terms of stability, maximum internal phase volume, and rheology. The optimal contact angle and particle concentration for modification were 105° and 3000 ppm, and under such conditions, the maximum internal phase volume fraction of the emulsions was increased to 85% and the viscosity by 40 times. In addition, the selected MMPs were then injected into multiple homogeneous cores of different permeabilities to verify the injectability and the viability to form W/O emulsions via pressure curves and NMR two-dimensional spectrum. The results showed that the modified particles can be injected into cores with permeability above 200 mD, but only in cores with permeability above 500 mD can a significant W/O emulsion be observed. Finally, three sets of heterogeneous core flooding tests were conducted in an online NMR system to determine the reasonable timing for injection of the MMPs and to verify its ability to enhance sweep efficiency by monitoring variations in NMR imaging, oil recovery, water cut, and pressure. Our work provides useful insights into the enhancement of sweep efficiency in heterogeneous heavy oil reservoirs by particle-stabilized W/O emulsions.

Impact of PAM-ZnO nanocomposite on oil recovery

A new nanocomposite (NC) comprising of ZnO nanoparticles and polyacrylamide (PAM) polymer hybrid agent is investigated for enhanced oil recovery in sandstone and carbonate rocks. A range of measurements are conducted to examine the behavior of NCs including NC synthesis and characterization, NC physical properties, stability analysis, IFT, and wettability as a function of NC concentration (from 100 to 1000 ppm). Furthermore, core flood tests are performed to evaluate oil recovery and relative permeability characteristics and a numerical model is established, and history matched.The zeta potential tests verified the stability of the set NC at 200 ppm concentration in water-based solutions, while a clear reduction in IFT from 29 mN/m to 5.5 mN/m was observed at the same NC concentration. A notable shift is observed in contact angle from 133° to 13° for the sandstone rock at a 1000 ppm NC concentration suggesting a significant shift in wettability from oil-wet to strongly water-wet after NC injection while the optimal contact angle for the sandstone occurred at NC concentration of 200 ppm. Furthermore, the flooding NCs resulted in a 16.05 % increase in oil recovery factor compared to seawater flood for sandstone while a 26 % increase was recorded for carbonate sample. Likewise, the mobility ratio after NC flooding compared to seawater flooding decreased from 8.56 to 1.46. We obtained a good history match of the water cut and oil recovery factor data by creating the core dimension model. In addition, according to the fluid distribution pattern (one of the simulator outputs), the fingering phenomenon was delayed after flooding the NC compared to seawater. This study provides new insights into the impact of nanocomposite on oil recovery enhancement in sandstone and carbonate formations.

Preparation and anti-corrosion performances of grass-like microstructured superhydrophobic surface on copper via solution-immersion

Blue-black grass-like microstructure film composed of orthorhombic Cu(OH)2 and monoclinic CuO were successfullysynthesized by immersing copper foils in 0.03 M ammonia solution at 15 °C for 36 h. After modified with heptadecafluorodecyltripropoxysilane, the microstructured surface becomes strongly super-hydrophobic with optimum water contact angle of 163.7° and a roll-off angle of ≤ 10°. Moreover, the super-hydrophobic surface exhibited excellent inhibition effect to the copper corrosion and stability in 3.5 wt% NaCl aqueous solution.

The effect of nitrogen concentration on the properties of N-DLC prepared by helicon wave plasma chemical vapor deposition

Nitrogen-doped diamond-like carbon (N-DLC) films were synthesized by helicon wave plasma chemical vapor deposition (HWP-CVD). The mechanism of the plasma influence on the N-DLC structure and properties was revealed by the diagnosis of plasma. The effects of nitrogen doping on the mechanical and hydrophobicity properties of DLC films were studied. The change in the ratio of precursor gas flow reduces the concentration of film-forming groups, resulting in a decrease of growth rate with increasing nitrogen flow rate. The morphology and structure of N-DLC films were characterized by scanning probe microscopy, Raman spectroscopy, and X-ray photoemission spectroscopy. The mechanical properties and wettability of N-DLC were analyzed by an ultra-micro hardness tester and JC2000DM system. The results show that the content ratio of N+ and is positively correlated with the mechanical properties and wettability of N-DLC films. The enhancement hardness and elastic modulus of N-DLC are attributed to the increase in sp3 carbon–nitrogen bond content in the film, reaching 26.5 GPa and 160 GPa respectively. Water contact measurement shows that the increase in the nitrogen-bond structure in N-DLC gives the film excellent hydrophobic properties, and the optimal water contact angle reaches 111.2°. It is shown that HWP technology has unique advantages in the modulation of functional nanomaterials.

Effect of The Composition of Hydrophobic Agents on The Contact Angle and Strength of Mortal Cement

Mortar cement resistance has serious economic implications in the form of maintenance costs and replacement of a structure. Therefore it is necessary to make cement mortar that is waterproof or hydrophobic. The purpose of this study was to look at the effect of the composition of hydrophobic agents on the large contact angle and strength of mortal cement. The hydrophobic agent used is Tetrahydrofuran (THF) with polyurethane (PU) with variations of 5:6molar, 1:10molar, 1:10.9 molar with total each variation being 11 molars. The control variables in this study are the amount of composition of otawa sand, aquades and silica sand 20-30 mesh which is 4:11:2 mold 5 cm x 5cm cement mortar cubes, long immersion with Ca(OH)2 10% for 7 days, temperature 60 °C and heating length 1 hour. The large angle of contact is measured using the caessyal drop method and the hardness value using the hardness vickers tool. The results showed that the higher the concentration of Polyuteran, the smaller the contact angle of mortar cement produced. The largest contact angle occurs at the concentration of THF variation: PU 6:5 mol. The optimum contact angle is 126° and the mortal seemen are hydrophobic.

Effect of composition CaCO3/polyurethane (PU) on contact angle of the surface and compressive strength of mortar

Infrastructure development, especially in the field of construction material technology, one of them is mortar. The water content greatly determines the energy performance and durability of the mortar. Water can enter building materials or mortar through rain. Damage caused by moisture is common, especially in areas with high moisture content. To solve this problems, a hydrophobic or water-repellent mortar was created, one of which was by using a hydrophobic additive, namely CaCO3/PU. The purpose of this research was to determine the effect of the composition of CaCO3/PU on the surface contact angle and mortar strength. This research uses spray coating method. The hydrophobic layer was made with various compositions of 5%, 10% and 15% and the carbonation temperature used was 60°C using an oven. This research resulted in optimum contact angle at 15% PU variation of 120.8936° and optimum compressive strength of 187,68 kg/cm2 at 10% CaCO3 immersion.