• Membrane and Water Treatment
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• v.2 no.1
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• pp.39-49
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• 2011

We investigated about the utilization improvement of the PDMS and fluoropolymers by mutual application in environmental analysis. We were conducted the direct fluorination with mild condition on the PDMS films and analyzed its surfaces before and after fluorination. The results of FTIR and SEM analysis on the PDMS films showed that the film surfaces were fluorinated without irreversible deformation by the fluorination. During the fluorination, the measured contact angles of water and several alcohols on the PDMS films decreased with time and that of most alcohols decreased to 0 after 30 minutes. The surface energy of fluorinated PDMS films has increased by 2 times. Also, we investigated the influence factors on the change of permeation rate of water through PDMS tubes with time. It was observed that the change of permeation rate of water through PDMS tube was affected by temperature, water phase and spatial distribution of water. From these results, we could verify the principal causes of the decrease of permeation rate of water through PDMS tube with time and proposed a new experimental setup for reducing the variation of permeation rate of water less than 2%.

• Journal of Industrial Technology
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• v.22 no.A
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• pp.249-254
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• 2002

The surface of tube-type alumina substrate was modified with a silane coupling agent in order to modify the membrane surface with hydrophobicity. Contact angle of water drops on modified membrane was greater than $90^{\circ}$. The modified membrane was tested in pervaporation and vapor permeation for the recovery of menthol from dilute menthol/water mixture. With increasing menthol concentration in the feed at $45^{\circ}C$, permeation rate of menthol in pervaporation and vapor permeation increased from $0.039(g/m^2hr)$ to $0144(g/m^2hr)$ and from. $0.077(g/m^2hr)$ to $0.297(g/m^2hr)$ respectively. When feed concentration is 0.005(g/L) at $45^{\circ}C$, separation factor for menthol in pervaporation and vapor permeation is 20,7 and 40.5 respectively.

• Journal of the Korean Applied Science and Technology
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• v.17 no.1
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• pp.43-48
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• 2000

Drug delivery system(DDS) applied to various fields, such as medicine, cosmetics, agriculture and necessities of life. Among these application fields, DDS is often used as the method of drug dosage into the epidermic skin. We investigated characters of transdermal therapeutic system(TTS) and the skin permeability of that with applying DDS. Chitosan was selected as material of TTS. We investigated the permeation of chitosan ointment containing drug in rat skin using horizontal membrane cell model. Permeation properties of materials were investigated for water-soluble drug such as riboflavin in vitro. We used glycerin, PEG 600 and oleic acid as enhancers. Since dermis has more content water(hydration) than the stratum corneum, skin permeation rate at steady state was highly influenced when glycerin was used in water-soluble drug. The permeation rate of content enhancer and drug was found to be faster than that of content water-soluble drug only. These results showed that skin permeation rate of drug across the composite was manly dependent on the property of ointment base and drug. Proper selection of the polymeric materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate.

• Membrane Journal
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• v.9 no.1
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• pp.43-50
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• 1999

The effects of water vapor on the permeation rates of oxygen and nitrogen through poly sulfone hollow-fiber membrane were investigated. The permeation rates of both 02 and $O_2$ were decreased significantly owing to the presence of water vapor. The permeation rate of oxygen with 100% relative humidity was reduced by as much as 20%, while the permeation rate of nitrogen decreased by 14% at 30 "C and 3kgf/$cm^2$ of upstream pressure. The permeation rates of $O_2$ were declined monotonously with running time and arrived at steady state values by the presence of water vapor. However, those of $N_2$ increased tentatively and then decreased to the steady state.tate.

• Journal of Ocean Engineering and Technology
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• v.22 no.4
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• pp.40-45
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• 2008

This paper describes the effects of fly ash replacement on the water tightness of antiwashout underwater concrete, which replaced the cement with fly ash from 0% to 30%. The experimental work was performed to find out the depth of permeation of concrete specimens cast in air and cured in 23 $^{\circ}C$ tap water using an open center pressure type of water permeation tester. The results showed that the permeation depth values of antiwashout underwater concrete were deeper than normal concrete, but that an admixture using fly ash during antiwashout underwater concrete casting in air made it more watertight than normal concrete according to the water permeation testing. SEM observations of the specimens of fly ash antiwashout underwater concrete showed that it wasmore packed with structures because of the pozzolan reaction of the fly ash and cement.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.179-184
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• 2000

The surface of porous alumina membrane was modified with silane coupling agent in order to enhance hydrophobicity. The contact angle of water to the surface-modified alumina membrane was greater than $90^{\circ}$. The surface-modified membrane was tested in vapor permeation for the concentration of aqueous ethanol. With the increase of ethanol concentration in the feed, permeation flux increased due to the greater affinity of ethanol with surface-modified alumina membrane than that of water. The experimental results showed that the permeation rate of surface-modified alumina membrane was 15~1000 times greater than that of polymer membranes.

• Journal of Electrochemical Science and Technology
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• v.9 no.3
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• pp.212-219
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• 2018

Perovskite type ceramic membranes which exhibit dual ion conduction (proton and oxygen ion conduction) can permeate water and can aid solving operational problems such as temperature gradient and carbon deposition associated with a working solid oxide fuel cell. From this point of view, it is crucial to reveal water transport mechanism and especially the nature of the surface sites that is necessary for water incorporation and evolution. $BaCe_{0.8}Y_{0.2}O_{3-{\alpha}}$ (BCY20) was used as a model proton and oxygen ion conducting membrane in this work. Four different catalytically modified membrane configurations were used for the investigations and water flux was measured as a function of temperature. In addition, CO was introduced to the permeate side in order to test the stability of membrane against water and $CO/CO_2$ and post operation analysis of used membranes were carried out. The results revealed that water incorporation occurs on any exposed electrolyte surface. However, the magnitude of water permeation changes depending on which membrane surface is catalytically modified. The platinum increases the water flux on the feed side whilst it decreases the flux on the permeate side. Water flux measurements suggest that platinum can block water permeation on the permeate side by reducing the access to the lattice oxygen in the surface layer.

• Journal of Environmental Health Sciences
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• v.43 no.1
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• pp.77-86
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• 2017

Objectives: The purpose of this study was to compare permeation characteristics in three skin types using oil-soluble benzoic acid and water-soluble caffeine after method condition optimization based on OECD guideline 428. Methods: A Franz diffusion cell, a reliable alternative method for skin permeation, was used. One-milliliter samples were taken and immediately replaced with fresh solution in the receptor chamber at regular time intervals (1, 2, 4, 7, 10 and 24 hr). The amount of test substances was measured by LC-MS/MS. Results: The permeation rate increased dose-dependently, and the permeation orders were $KeraSkin^{TM}$ > hairless mouse full skin > human cadaver epidermis for skin types, and benzoic acid solution > caffeine solution > benzoic acid cream > caffeine cream for type of test materials. Conclusion: According to the definitions of Marzulli, benzoic acid and caffeine would be classified as 'fast' and 'moderate' compared with the permeation of other chemical species. The setting conditions and permeation characteristics performed in this study are expected to contribute to future permeation studies.

• Membrane Journal
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• v.6 no.1
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• pp.22-31
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• 1996

Pervaporation experiments of isopropanol-water mixtures through a polydimethytsiloxane(PDMS) membrane were carried out at 35$^{\circ}$C and the effect of isopropanol concentration on the separation characteristics was investigated. The total permeation rate showed the largest deviation from the ideal permeation rate at the isoprpanol volume fraction from 0.5 to 0.7, which resulted from the interaction effect between permeants. The plasticizing effect of isopropanol enhanced the permeation of water, while the existance of water resulted in the depression of isopropanol permeation. Both the permeation rate and the selectivity were predicted using Flory-Huggins thermodynamics and modified Maxwell-Stefan equation. The concentration-dependent diffusion coefficients were expressed by Vignes equation. The Flory-Huggins interaction parameter between isopropanol and water was calculated using excess Gibbs energy correlation and the interaction parameters between liquid and polymer membrane were determined by equilibrium swelling experiments. The predicted permeation rates were in accord with the experimental ones within maximum error range of 35 %. The predicted permeation selectivities were in good agreement with the experimental values.

• Journal of Environmental Health Sciences
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• v.26 no.2
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• pp.91-96
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• 2000

We investigated characters of transdermal therapeutic system(TTS) and the skin permeability of that with applying drug delivery system(DDS). Natural gums were selected as material of TTS. The permeation of natural gums ointment containing drug in rat skin using diffusion cell model. Permeation properties of materials were investigated for water soluble drug such as riboflavin in vitro. We used glycerin, PEG 600 and oleic acid as enhancers. Since dermis has more hydration than the stratum corneum, skin permeation rate at steady state was highly influenced when glycerin was used in riboflavin. The permeation rate of content enhancer and drug was found to be faster than that of content riboflavin only. These results showed that skin permeation rate of drug across the composite was mainly dependent on the property of ointment base and drug. All the gum ointment tested showed good safety. Proper selection of the materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate.