• Journal of Integrative Natural Science
• /
• v.6 no.4
• /
• pp.211-214
• /
• 2013

In this study, in order to investigate how consecutive treatments of glass surface with HF acid and water vapor/Ar plasma affect the quality of 3-aminopropyltriethoxysilane self-assembled monolayer (APS-SAM), poly(3,4-ethylenedioxythiophene) (PEDOT) thin films were vapor phase-polymerized immediately after spin coating of FeCl3 and poly-urethane diol-mixed oxidant solution on the monolayer surfaces prepared at various treatment conditions. For the film characterization, various poweful tools were used, e.g., FE-SEM, an optical microscope, four point probe, and a contact angle analyzer. The characterization revealed that HF treatment is not desirable for the synthesis of a high quality PEDOT thin film via vapor phase polymerization method. Rather, sole treatment with plasma noticeably improved the quality of APS-SAM on glass surface. As a result, a highly dense and smooth PEDOT thin film was grown on uniform oxidant film-coated APS monolayer surface.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2006.06a
• /
• pp.43-49
• /
• 2006

The surface and pore structure of cellulose fibers have a significant impact on the properties and performance in applications. Cellulase enzymatic hydrolysis of cellulose fibers can result in changes to the surface and pore structure thus providing a useful tool for fiber modification. This research characterizes these changes using various test methods such as fiber dimension, water retention value, hard-to-remove water content, freezing and non-freezing bound water content, polymer adsorption, and crystallinity index. For a high-dosage enzyme treatment (0.10 g/g), the fiber length was significantly decreased and the fibers were 'cut' in the cross direction, not in the axial direction. The swelling capacities as measured by the WRV and HR water content increased for the high-dosage treatment. Three independent measurements (non-freezing bound water, polymer adsorption, and crystallinity index) are in good agreement with the statement that the amorphous regions of cellulose fibers are a more readily available substrate relative to crystalline regions. Based on the experimental results obtained herein, a model was proposed to explain surface and pore structure modification of cellulose fibers via enzymatic treatment.

• 한국전산유체공학회:학술대회논문집
• /
• 2011.05a
• /
• pp.54-57
• /
• 2011

In this paper we present an algorithm about how to simulate two dimensional dam breaking with lattice Boltzmann method (LBM). LBM considers a typical volume element of fluid to be composed of a collection of particles that represented by a particle velocity distribution function for each fluid component at each grid point. We use the modified Lattice Boltzmann Method for incompressible fluid. This paper will represent detailed information on single phase flow which considers only the water instead of both air and water. Interface treatment and conservation of mass are the most important things in simulating free surface where the Interface is treated by mass exchange with the water region. We consider the surface tension on the interface and also bounce back boundary condition for the treatment of solid obstacles. We will compare the results of the simulation with some methods and experimental results.

• Journal of the Korea Institute of Building Construction
• /
• v.15 no.6
• /
• pp.561-567
• /
• 2015

The research, in order to enhance the quality of recycled aggregate, was carried out the quality characteristics test of the recycled aggregates by applying the four kinds of surface treatment using a colloidal suspension of approximately 5nm~60nm particle size with the alkalinity of pH 10.2. The quality tests of recycled aggregate have been processed by specific gravity, water absorption, porosity, surface properties, and the compression and tensile tests. The colloidal suspension was coated effectively the surface of the old cement mortars of recycled aggregate with a constant thickness by colloidal suspension is being applied to the recycled aggregate surface under constant pressure of 100kpa and then it was dried in at $60^{\circ}C$. The surface treatment method by the Method C out of 4 kinds of surface treatment improved effectively the quality of the recycled aggregates, whereby it obtained the best compressive strength and tensile strength of the recycled aggregate concrete.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2011.10a
• /
• pp.36.2-36.2
• /
• 2011

Titanium and its alloys have been widely used for orthopedic implants because of their good biocompatibility. We have previously shown that the crystalline titania layers formed on the surface of titanium metal via anodic oxidation can induce apatite formation in simulated body fluid, whereas amorphous titania layers do not possess apatite-forming ability. In this study, hot water and heat treatments were applied to transform the titania layers from an amorphous structure into a crystalline structure after titanium metal had been anodized in acetic acid solution. The apatite-forming ability of titania layers subjected to the above treatments in simulated body fluid was investigated. The XRD and SEM results indicated hot water and/or heat treatment could greatly transform the crystal structure of titania layers from an amorphous structure into anatase, or a mixture of anatase and rutile.The abundance of Ti-OH groups formed by hot water treatment could contribute to apatite formation on the surface of titanium metals, and subsequent heat treatment would enhance the bond strength between the apatite layers and the titanium substrates. Thus, bioactive titanium metals could be prepared via anodic oxidation and subsequent hot water and heat treatment that would be suitable for applications under load-bearing conditions.

• Membrane and Water Treatment
• /
• v.15 no.3
• /
• pp.139-152
• /
• 2024

Mixed matrix membranes have gained significant recognition in the wastewater treatment industry for their effectiveness in removing dyes, proteins, and heavy metals from water sources. Researchers have developed an innovative technique to enhance properties of these membranes by incorporating amine-functionalized carbon nanotubes into the polymer matrix. This approach introduces amine functional groups onto the membrane surface, which are then modified with trimesoyl chloride and cyanuric chloride. The modified membranes are characterized by XPS to confirm successful bonding of amines with the trimesoyl chloride and cyanuric chloride. The surface charge of the modified membrane also plays a role in the modification process; the membrane modified with trimesoyl chloride has a negative surface charge, while the one modified with cyanuric chloride has a more positive charge. At the same acidic pH, the positive or negative charge of the mixed matrix membranes assists in enhancing the rejection of heavy metals. This results in improved antifouling properties for both modified membranes. The heavy metal rejection for all modified membranes is higher than for unmodified membranes, due to both adsorption and complexation abilities of the functional groups on the membrane surface with heavy metal ions. As the membrane surface functionalities increase through modification, the separation due to complexation also increases. The bulk morphology of the membrane remains unchanged, while roughness slightly increases due to the surface treatment.

• Journal of the Korean institute of surface engineering
• /
• v.41 no.2
• /
• pp.63-68
• /
• 2008

Traditionally and generally used calcined clay was carburized, and its characteristics were studied. Carburization treatment was performed by the thermally decomposed carbon and the deposit carbon which occur in a so called 'Boudouard reaction $(2CO{\rightarrow}CO_2+C)'$ at fuel combustion process in a closed-type furnace. The color of the carburized calcine clay changed from yellow to black, and the carbon component revealed as crystalline graphite by the X-ray diffraction test. The weight of the carburized calcine clay decreased to about 4 wt.% by the 1st heating to $1400^{\circ}C$ in air but it does not decreased by the 2nd heating of the same conditions. By the carburization treatment, the water absorption changed from 13 wt.% to 6 wt.%, and the contact angle for water drop changed, too, from 0 to $87^{\circ}$ which was tested by the photograph of one minute after a water drop contact. It means the carburized calcine clay does not absorb water drop so it has a hydrophobic characteristic.

• Advances in concrete construction
• /
• v.7 no.3
• /
• pp.191-201
• /
• 2019

Bamboo concrete bond behaviour is investigated through pullout test in this work. The bamboo strip to be used as reinforcement inside concrete is first treated with chemical adhesive to make the bamboo surface impermeable. Various surface coatings are explored to understand their water repellant properties. The chemical action at the bamboo concrete interface is studied through different chemical coatings, sand blasting, and steel wire wrapping treatment. Whereas mechanical action at the bamboo concrete interface is studied by developing mechanical interlock. The result of pullout tests revealed a unique combination of surface treatment and grooved bamboo profile. This combination of surface treatment and a grooved bamboo profile together enhances the strength of bond. Performance of a newly developed grooved bamboo strip is verified against equivalent plain rectangular bamboo strip. The test results show that the proposed grooved bamboo reinforcement, when treated, shows highest bond strength compared to treated plain, untreated plain and untreated grooved bamboo reinforcement. Also, it is observed that bond strength is majorly influenced by the type of surface treatment, size and spacing of groove. The changes in bamboo-concrete bond behavior are observed during the experimentation.

• Journal of the Korean institute of surface engineering
• /
• v.51 no.6
• /
• pp.337-343
• /
• 2018

The present study investigated the effect of heat treatment process on the surface wettability of an Al-Si-Mg alloy. After solution-treated at $525^{\circ}C$ and aged at $160^{\circ}C$, the alloy showed high hardness due to the formation of precipitates. In addition, surface wettability was improved in such a way that the contact angle of distilled water droplet on the flat surface decreased to $37.6{\sim}42.1^{\circ}$ after the heat treatment. The surface energy predicted by Owens-Wendt equation also confirmed the increase of surface energy after the heat-treatment. However, when the surface roughness increased, the positive effect of the heat treatment on wettability diminished due to the geometrical factors of the rough surface.

• Membrane and Water Treatment
• /
• v.6 no.4
• /
• pp.323-337
• /
• 2015

Membrane Fouling was considered as major drawback in various industrial applications. Thus, this paper reviews the surface modification of polyethersulfone (PES) membranes for antifouling performance. Various modification techniques clearly indicate that hydrophilicity has to improve on the PES membrane surface. Moreover, the mechanism of fouling reduction with corresponds to various modification methods is widely discussed. Incorporation of hydrophilic functional groups on PES membrane surface enhances the surface free energy thereby which reduces the fouling. Characterization techniques adopted for the surface modified membranes was also discussed. These studies might be useful for the other researchers to utilize the modification technique for the applications of waste water treatment, chemical process industry and food industry.