Papers by Keyword: Hydrophobic

Abstract: The surfaces with characteristic of water repellent, corrosion resistance and self-cleaning is important to achieve for the commercial application. The uses of hydrophobic on the compressed oil palm trunk (OPT) give opportunity for OPT become the potential product for indoor and outdoor furniture application and paneling by increase the characteristic of OPT surface with variances parameter. In this study, the characteristic and behavior of OPT was determined by investigates the functional groups exist in samples and the bonding force between them using Fourier transform infrared (FTIR) spectroscopy that show the similar pattern of hydrophobic OPT and silica nanoparticles. This research also focuses on study the swelling and shrinkage behavior of hydrophobic OPT with uncoated OPT by experimental approach that resulted on average of 20% less water absorption level and 38% reduction of thickness swelling compared to uncoated OPT.

Abstract: In this work, hydrophobic of modified SiO₂ coating for self cleaning material were prepared by dip-coating methods and solvothermal manual. SiO₂ was successfully prepared from silica sand by purified followed sol-gel methods. Tetraetoxysilane (TEOS) and Hexamethyldisilanze (HMDS) were used as surface chemical modification agents with varied mass of SiO₂, which were 1, 2, 3, and 4 g. X-ray fluorescence spectrometer (XRF) , X-ray powder diffraction (XRD), Particle size analyzer (PSA), Ultraviolet–visible spectrophotometer (UV-Vis), and Water contact angle (WCA) were employed to investigate the element composition, crystal structure, size of particles, transparency, and hydrophobicity of coating. The results indicated that modified SiO₂ coatings has hydrophobic feature as self cleaning material (WCA > 90˚) for indium tin oxide (ITO) glass.

Abstract: The objective of this project was to develop the hydrophobic film for self-cleaning glasses. The effects of octyltriethoxysilane (OTES) additions to hydrolysis of tetraethylorthosilicate (TEOS) on hydrophobic and optically transparent properties were studied. The film was prepared by sol-gel method from the precursors namely, TESO, OTES, isopropanol alcohol (IPA), and deionized water (DI). The sols for coating were obtained with TEOS/OTES ratio of 50:50 to 99:1. The sols were deposited on a commercial glass and dried at 60oC for an hour. After drying, the film properties were characterized by fourier transform infrared spectroscopy (FTIR), UV-VIS Spectrophotometer, x-Ray Diffractometer (XRD), atomic force microscope (AFM), optical microscopy and contact angle meter. It was found that contact angles of the hybrid films increased with the OTES addition, reaching a maximum at 10 wt.%, and the contact angle values were the same as for further addition. The light transmittance was rather stable with increasing amounts of OTES. For the optimized condition, the water contact angle of 108o and light transmittance of 91%, was obtained with TEOS/OTES ratio of 90:10.

Abstract: This work aims to study the effect of SiO₂ and heat treatment temperature in TEOS-SiO₂-OTES film on the hydrophobic property and weathering durability. TEOS-SiO₂-OTES film was prepared by sol-gel process. Tetraethylorthosilicte (TEOS) and Octyltriethoxysilane (OTES) were used to form the gel. The contents of SiO₂ were varied at 0.5% 1% 3% 5% and 10% by weight. The film was deposited on a glass slide by spin coating. The hydrophobic property was studied by FTIR, UV-VIS spectroscopy, SEM, XRD and contact angle. The weathering chamber was used for studying weathering durability. The weathering condition was controlled at 50 oC and 85%RH. Moreover, the chemical resistant was also tested. The study showed that the silica contents affected the surface roughness of film. The surface roughness of film decreased with increasing amounts of SiO₂.

Abstract: The separation of oil from water is significance for environmental de-pollution application. To obtain selectivity of liquid, filter papers were coated to bear highly hydrophobic and oleophilic functionality that can allow only oils to pass through them. The coating solutions were prepared by mixing poly(methylhydro siloxane, PMHS) and fumed silica at various proportions. To determine an optimum coating condition, properties of the treated filter papers were investigated by measuring water contact angle and surface free energy, examining surface morphology and testing for selective removal of diesel oil from water. The optimum coating solution was at the PMHS:fumed silica weight ratio of 1.25:1.00. The treated filter paper exhibited high hydrophobicity with water contact angle of 142.80 ± 0.36 degrees and surface free energy of 0.78 mJ/m². In addition, it exhibited high selective removal of diesel oil from water with oil absorption capacity of 2.3 g/g.

Abstract: The aim of the research is to subject the three different silanes to chemical and electrochemical investigations in other to determine the most efficient organic compound. Three types of hydrophobic silanes [Tris (Trimethylsiloxy) silyethyl] dimethylchlorosilane (Alkyl); Tridecafloro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS) and Henicosyl-1,1,2,2-tetrahydrododecyltricholrosilane (FDDTS) are presented and investigated. The three silanes are of different composition but are deposited at the same parameters and conditions. The chemical investigation was studied through (attenuated total reflection Fourier-transform infrared (ATR-FTIR) and x-ray diffraction (XRD), while the electrochemical study was conducted through EIS using natural seawater electrolyte at room temperature. From the investigation techniques, only electrochemical impedance results show that FDDTS performed better than both Alkyl and FOTS. The chemical analysis showed the presence of hydrophobic silane on all the coated samples, and no distinction can be drawn from associated peaks.

Abstract: Mangosteen peel powder is one of the most important bio-antioxidants. Adding mangosteen peel powder as filler into natural rubber latex compound for latex glove film formation via dipping process can help the green anti-microbial properties. The physical (smoothness and thickness of film) and mechanical properties (tensile strength and elongation at break) of latex film are still good. Therefore, adding mangosteen peel powder into natural rubber latex gloves can reduce the anti-allergic and antimicrobial on the film surface. Mangosteen peel powder ground by rapid mill is fine particle and high surface area 2.4216 m²/g suitable for homogeneous and compatible for adding into natural rubber latex compound. Ceramic hand mold was dipped into the Ca (NO₃)₂ coagulant only 3 seconds, then dipped into the natural rubber latex compounds added mangosteen peel powder for 15 seconds, withdrawn hand mold slowly, cured in the oven at 120°C for 30 min, then dried at room temperature, and casted it off the hand mold. The obtained natural latex glove films added mangosteen peel powder are smooth, clear, and thin film surface, the highest elongation at break 803.2711 ± 31.6477%, good tensile strength 30.2933 ± 6.0218 MPa, dense film without water leakage, and good contact angle.

Abstract: In a previous study, we presented new method measurement rheological properties of hydrophobized plaster in dependence of hardening time. Influence of external temperature on pozzolana plaster is analyzed in this paper, especially plasticity and workability of paste. Main aim of rheological test is determination of flow curves, obtained by applying a succession of constant strain rates for short times at the temperature 10°C and 30°C. Base on the performed experiments, it can be concluded that the temperature have very significant influence on rheological properties of plasters. With an increase in temperature, the application time of the mixture is shorter, from hour to minutes. A comparative measurement with pure lime plaster was done as well.

Abstract: The influence of time on rheological properties of modified lime plaster is analyzed in this paper. Effect of composition of mixture is examined as well. Especially changes of paste due to hydrophobic and pozzolanic admixture. Main aim of rheological test is determination of flow curves, obtained by applying a succession of constant strain rates for short times. Base on performed experiments, it can be concluded that hydrophobic admixture eliminated influence of pozzolana. Also both time and temperature caused significant changes in rheological properties. Increasing values decreases the flow characteristic of the plaster. A comparative measurement with pure lime plaster was done as well.

Abstract: Thermoplastic urethane (TPU) nonwoven is characterized by high elasticity, tensile strength, large elongation and structural stability and widely used in biomaterial. However, the hydrophobic nature of TPU nonwoven restricts its application. To improve surface hydrophilicity and hydrophobicity, the surface modification of materials is carried out by plasma treatment or ion-beam irradiation. According to the wettability treatment experiences that substrate usually using two processing or more to get one side hydrophilic and another side hydrophobic. In this study, use of cold plasma treatment in enhancing surface wettability of TPU nonwoven was studied. The surface properties of plasma treated films are characterized by Atomic Force Microscope (AFM), water contact angle measurement, and scanning electron microscopy (SEM). This study has demonstrated that Argon plasma treatment produces hydrophobic or hydrophilic surface on the TPU nonwoven. The method is performed by first placing a hydrophobic material on one side of substrate and bring this side to face the lower electrode. By controlling the RF power of the reactor, hydrophilic or hydrophobic surface can be prepared on the other side. This technique can be applied to wound dressing.