Papers by Keyword: Hydrophilic

Abstract: Foam flooding is a promising enhanced oil recovery (EOR) while improving the gas sweep efficiency problem of gas flooding. On the other hand, nanotechnology has paved the way for utilizing nanoparticles in surfactant foam while improving foam stability, lamella thickness, bubble size distribution, and oil recovery. The significant difference between nanoparticles and surfactants as foam stabilizers is the adsorption energy of nanoparticles at gas-liquid interfaces, which is thousands of times bigger than surfactants. However, previous studies on nanoparticles' foam adsorption energy are limited by using only nanoparticles (in the absence of surfactants), though it is hard to generate foam since it does not reduce surface tension significantly. Thus, the objective of this study is to determine the adsorption energy of hydrophilic silicon dioxide (SiO2) and partially hydrophobic silicon dioxide (PH SiO2) nanoparticles in the presence of anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethylammonium bromide (CTAB) surfactants. Another objective is to analyze and evaluate the effects of adsorption energy on foam stability. Consequently, the particle radius, surface tension, and particle surface wettability were all obtained from the maker, Du Noüy ring tensiometer, and particle surface contact angle. The result shows that the adsorption energy of PH SiO2 was a thousand times greater than hydrophilic SiO2 in the presence or absence of surfactants. Due to PH SiO2 having a slightly bigger particle radius, higher adsorption energy in the PH SiO2 system is mainly by particle hydrophobicity and surface tension. In all systems, the highest adsorption energy is achieved at the lowest concentration of nanoparticles because the increment in nanoparticle concentration reduces the surface tension, eventually lowering the adsorption energy. However, this trend is contradicted with half-life foam stability when it increases with the nanoparticles concentration until the optimum concentration is obtained, then reduced. To sum up, the evaluation of the nanoparticles' foam adsorption energy in this study supports the fundamentals of nanoparticles stabilizing foam that are also influenced by other parameters: the maximum capillary pressure, particle arrangements during film drainage, and growing aggregate and the ‘cork’ formation inside lamella.

Abstract: The surface wettability of metallic biomaterials significantly influences the biological response of biomedical implants. However, the optimal degree of wettability depends on the specific coating or surface treatment applied to the biomaterial. Researchers have widely utilised hydroxyapatite coatings to modify implant surfaces to enhance bioactivity, biocompatibility, and osseointegration. This review article discussed the impact of hydroxyapatite-doped coatings on the surface wettability of metallic biomaterials. A systematic search of Scopus and Web of Science databases was conducted to review recent studies investigating the wettability and biological response of hydroxyapatite-doped coatings applied through standard implant surface deposition techniques. Results reveal that hydroxyapatite-doped coatings are typically hydrophilic and have higher surface energy than uncoated hydrophobic metallic surfaces. The hydrophilic nature promotes better interaction with biological fluids, resulting in cell adhesion and proliferation. The rough and porous surface increases wettability as fluid can easily penetrate the craters. Further research may elucidate the complex connectivity of deposition method process parameters with surface wettability and biological outcomes. This review briefly overviews current research on hydroxyapatite-doped coatings and their effects on surface wettability and biointegration.

Abstract: The dust accumulation and dirt particles always degrade the transparency of glass, later hampers its various applications such as photovoltaic panels, building glass, and car-windshield. In this study, the hydrophilic self-cleaning coatings have been developed by using the nanocalcium Carbonate particles (nanoCaCO₃) and hydrophilic micro-titanium dioxide particles (µ-TiO₂). The presence of oxide groups, CO^-3 and TiO^2- forms a strong attraction of glass to polar water molecules. At the weight ratio of 1: 1 in the CaCO₃ to TiO₂ mixture, it forms a great hydrophilic property in which the water contact angle (WCA) of coated glass has been recorded as low as 11.46 ±0.85°. The coated glass also showed high transparency in UV and Visible regions. The optical transmission of coated glass was above 89% at the wavelength of 300-400nm and above 97% at the wavelength of 400-800nm. Due to its hydrophilic property, the coated glass is capable of removing the dust particles away via the water stream. The hydrophilic coating spontaneously forms the water-thin film after contact with coated glass without the presence of UV light.

Abstract: Titanium based metallic biomaterials for orthopedic implant applications are often associated with biocompatibility problems which can be ameliorated via proper surface modification strategies. Improving the hydrophilic nature of the titanium surface offers an effective strategy to sort out such limitations by intensifying the cellular activity. Development of titania as well as titanate layers on the titanium surface via alkali treatment represents an effective strategy to improve the hydrophilicity of native titanium surface. Inspired from nature, in the present work, we report the formation of three-dimensional (3D) hierarchical nanoflowers resembling Gomphrena globosa flowers developed on commercially pure titanium (cp-Ti) surface via a facile alkali treatment technique. X-ray diffraction studies evidenced anatase and rutile phases of TiO₂ confirming the development of titania on the surface. In addition to the TiO₂ phase, presence of titanate (Na₂Ti₃O₇) has also been observed as alkali treatment was conducted in NaOH solution. The hydrophilicity of the Ti surface has been enhanced after the alkali treatment as evidenced from wettability studies using static contact angle measurements. This increase in hydrophilicity is due to the enrichment of the surface by TiO₂ and titanate and increased roughness of nanoflower surface based on classical Wenzel law. In addition, the alkali-treated surface demonstrated an increased polar surface energy beneficial for biocompatible surfaces.

Abstract: Micro-porous hydrophilic membranes were successfully fabricated using polystyrene waste by phase inversion casting. Four concentrations (20, 25, 30, and 35 wt%) of recycled high-impact polystyrene (HIPS-R) in N, N-dimethyl formamide (DMF) solution were employed to prepare the membranes. The effect of polystyrene concentration on the characteristics of the different membranes was thoroughly studied. Based on the Fourier transform infrared spectroscopy (FTIR) results, the chemical composition of HIPS-R was analogous to that of pure high-impact polystyrene HIPS raw material of the previous studies. Also, field-emission scanning electron microscopy (FESEM) was employed to study the morphology and porosity of the prepared membranes. The membranes cross-section showed a sponge structure with longitudinal macro voids. The solid walls around these voids have a sponge-like structure, especially for high concentration polystyrene membranes. Furthermore, the number of pores into the membrane surface decreased with the increase of polystyrene concentration. The membranes surface pores size was ranged from 150 nm to 550 nm with the different used concentrations. Water contact angle (CA) of the prepared membrane's surface were measured. All the measured CA of the prepared membranes, except the 35 wt% showed CA of 91^o, showed a hydrophilic behavior. Thus, the results suggest effective membranes could be obtained using recycled polystyrene. And then, solve the polymer waste accumulation problem in parallel with help in drinking water crisis solution.

Abstract: Nanofibers membrane are potential material for water filtration, and surface properties of the membrane are an important factor to avoid fouling on the membrane surface. The combination of filter material is known to influence the membrane surface properties. We investigated the mixture of polyacrylonitrile (PAN) and cellulose acetate (CA) on the nanofiber membrane by electrospinning. This blend was dissolved in dimethylformamide as feed polymer in electrospinning technique. We prepared the ratio of PAN to CA were 0:10, 4:6, 5:5, 6:4, and 10:0 in 8 wt%. All the membranes formed fiber, except 0:10 which only created a thin layer from the sprays. Contact angle measurements related to membrane surface properties were measured and resulted in 128^o, 126^o, and 125^o for 4:6, 5:5 dan 6:4 membranes, respectively. This results indicated that all PAN/CA membranes had hydrophobic properties. The hydrophobic property was also observed by Fourier transform infrared (FTIR) spectroscopy, a sharp peak of-CH₃ appeared. It is interesting while mixing two hydrophilic polymers we obtain a hydrophobic membrane.

Abstract: Phytonutrients extracted from natural resources are receiving much attention among researchers due to their highly antioxidative characteristics which prevent several degenerative diseases including cardiovascular diseases and cancers. These nutraceutical compounds can be used in food, pharmaceutical and cosmetic products as natural antioxidants, preservatives, colourings and functional foods. Though much works have been reported on the extraction process, there are concerns on the health and safety risks posed by the commonly used organic solvents derived from petrochemical industry. Thus, there is a need to recover the phytonutrients using green, sustainable, efficient and low cost solvents that are safe for human consumption. This work discusses natural deep eutectic solvent (NADES) as a potential solvent to extract both polar and non-polar phytonutrients simultaneously from natural resources. Previous attempts (in the most recent 3 years) to make use of NADES as an extractant to obtain phytonutrients are presented. The synthesis process of NADES and current challenges when employing NADES are also being reviewed.

Abstract: An atmospheric pressure surface dielectric barrier discharge (SDBD) was used for surface treatment of Polypropylene (PP) and Polyethylene (PE) nonwoven fabrics which are widely used in filtration media, oil adsorbents, biomedical textiles, etc. The SDBD reactor has been built using the Printed Circuit Board (PCB) which is an inexpensive material available in the local market. The use of the PCB led to the ease of fabrication of a low-cost discharge electrode system that can be scaled up without difficulty. The effect of the plasma treatment on the hydrophilic behavior of the treated samples was studied using water contact angle (WCA) measurements. The microstructure of the PP and PE nonwoven fabrics before and after plasma treatment was characterized by Scanning Electron Microscopy (SEM). The results showed that the plasma treatment converted the fiber surface from smooth to textured surface. This resulted in enhancing the wettability of both materials but with more pronounced effect on the PP.

Abstract: Polysulfone (PSf) is one of the commonly used polymeric membrane materials due to its excellent properties. One of the major concern however is that PSf membranes are mostly hydrophobic in nature. The presence of fillers like halloysite nanotubes (HNTs) into the polymer matrix can decrease this hydrophobicity and may also alter some of its important properties. This study focused on the fabrication of nanofibrous membranes by electrospinning method and characterization using SEM, UTM and contact angle goniometer to determine the effect of HNT concentration to the membrane’s surface morphology, mechanical properties and wettability. Results showed that samples subjected at the highest voltage produced finer fibers. The initial addition of HNTs also creates fiber strands with smaller diameters until beading in the fibers due to perturbation of the polymer jet caused by the increased viscosity of the solution and particle agglomeration was observed at higher concentrations. In terms of response to mechanical load, the tensile strength was higher upon HNT integration showing an effective transfer of stress to the dispersed phase despite the morphological imperfections. The contact angle results showed a decrease in hydrophobicity at the highest HNT concentration reflecting the water-loving character of the filler. The overall data gathered showed that the addition of nanoclay improved the properties of PSf matrix making them a suitable material for different filtration applications particularly in water treatment systems.

Abstract: In this study, the certain chloromethylated polysulfone ultrafiltration membrane (CMPSF) was prepared via nonsolvent-induced phase separation (NIPS) method. Then the hydrophilic monomer was grafted on the CMPSF membrane through quaternary amination reaction. The structure of membrane was characterized by Fourier transform infrared and the properties were measured by pore size, contact angle and membrane water flux. The contact angle test results show that the hydrophilic performance of the membrane is improved due to the grafting modification. Meanwhile, water flux has a tendency to decrease with the increase of the reaction time due to the decrease in pore size. This indicates the rejection of membrane will be improved.