Wettability of microstructured Pyrex glass with hydrophobic and hydrophilic properties

Lee, Dong-Ki,Cho, Young Hak,Lee, Jong Whi,Park, Min Soo Elsevier Sequoia 2017 Surface & coatings technology Vol.319 No.-

<P><B>Abstract</B></P> <P>A grooved hybrid surface that has silane-coated surface (hydrophobic surface) on ridges and uncoated surface (hydrophilic surface) inside groove was fabricated on a Pyrex glass substrate through the laser-induced backside wet etching (LIBWE) process. The wettability characteristics of the grooved hybrid surface were evaluated from static contact angles (CAs) measured in parallel and orthogonal directions. With an increase in the width of the hydrophobic ridge, the CAs increased from 24° to 104° in the parallel direction. Consequently, the anisotropic wetting property of the fabricated hybrid surface was confirmed. Results of moisture condensation experiments indicated that moisture condensed rapidly in the hydrophilic grooves. Furthermore, the diffuse reflection of light was prevented when the groove was completely filled with water.</P> <P><B>Highlights</B></P> <P> <UL> <LI> New grooved hybrid surfaces with hydrophobicity and hydrophilicity was fabricated on a Pyrex glass. </LI> <LI> The laser-induced backside wet etching (LIBWE) process was used for machining a glass surface. </LI> <LI> Hybrid surfaces influence the wettability and condensation of water. </LI> <LI> Water filled the hydrophilic surface of the groove, not the hydrophobic surface of the ridge. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Corrosion resistance of water repellent aluminum surfaces with various wetting morphologies

Song, Kyounghwan,Kim, Inkyu,Bang, Soosik,Jung, Jung-Yeul,Nam, Youngsuk Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.467 No.-

<P><B>Abstract</B></P> <P>We investigated the improved corrosion resistance of micro/nanostructured aluminum surfaces by varying wetting morphologies. By combining the wet-chemical oxidation schemes and low surface energy coating, we induced three different wetting morphologies including superhydrophilic, Cassie-mode superhydrophobic and Wenzel-mode hydrophobic on micro/nanostructured aluminum surfaces. The superhydrophilic oxide layers provided approximately 30–76% improvement in the corrosion resistance compared to untreated ones. When a hydrophobic coating was added to the oxide layers and Cassie-mode superhydrophobicity was induced, all types of samples showed over 95% increase in the corrosion resistance compared with untreated ones. When the air trapped on the superhydrophobic surfaces was removed in a vacuum environment, the corrosion resistance decreased but still provided 70–98% increase compared with untreated ones. The present work showed that the superhydrophobic treatment is a very effective way to improve the corrosion resistance but the proper choice of the passivation layer and hydrophobic coating can provide a meaningful increase in the corrosion resistance. The present work further clarified the high corrosion resistance of superhydrophobic aluminum surfaces and will help to develop practical anti-corrosion resistance surfaces.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The effects of various wetting morphologies on the corrosion resistance were quantified. </LI> <LI> The importance of the air trapping was clarified by forcing the Cassie-to-Wenzel wetting transition. </LI> <LI> The effects of oxide barriers, hydrophobic coating and air layer on the corrosion resistance were analyzed. </LI> <LI> This work helps to estimate the effects of the surface degradation of anti-corrosion surfaces. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Lyocell/Wood pulp 섬유를 활용한 Wet-laid Nonwoven 시트의 특성

권순완,이용주,이도영,최정락,김형진 한국펄프·종이공학회 2024 펄프.종이기술 Vol.56 No.2

. Nonwoven fabrics are widely utilized in various industries due to their excellent bulk characteristics, productivity, and flexibility. With increasing global interests in environmental sustainability, there is a growing trend towards utilizing biodegradable and renewable raw materials in nonwoven production. In this study, we employed papermaking technology to fabricate wet-laid nonwoven fabric using Lyocell, a natural regenerated cellulose fiber, and wood fiber. We aimed to investigate the influence of fiber selection and mixing ratio on mechanical and surface properties. Mechanical property analysis revealed that the inclusion of wood fiber led to improve strength while reducing bulk due to the low density and smooth surface structure of Lyocell. To analyze surface characteristics, surface roughness and surface friction were analyzed, and as a result of analyzing each parameter, the coefficient of determination (R2) of the two parameters was 0.02, which was analyzed as an independent variable. Therefore, it was judged that a complementary approach considering both variables was necessary. As a result of surface roughness analysis, it was difficult to identify significant differences due to increasing the ratio of lyocell to wood fiber. However, as a result of the surface friction analysis, the F-MAD of the wet nonwoven fabric made only with Lyocell fiber showed a value of 0.043, and the value decreased when 50% wood fiber was mixed, confirming the possibility of improving softness. Furthermore, the analysis highlighted the influence of fiber length and width on softness, suggesting the importance of fiber characteristics in nonwoven fabrication. Overall, our findings suggest that incorporating wood fibers in wet-laid nonwoven manufacturing can enhance both strength and softness. These results provide insights for future nonwoven manufacturing technologies and quality control strategies.

석면 함유 슬레이트 지붕 철거작업시 주변 환경평가에 관한 연구

정다위,유혜영,박호연,윤철우,김용준,이지영,신선경,오길종 한국폐기물자원순환학회 2013 한국폐기물자원순환학회지 Vol.30 No.1

In this study, asbestos in air during dismantlement and removal of slate roof tiles and asbestos that could linger in mask filter and safety wear were investigated. In addition, a wetting agent and its physical properties for water were studied, while the possibility of prevention of drift was assessed based on the properties. According to the analysis of 100 air samples, asbestos concentrations ranged from 0.001 to 0.007 f/cc and the average was 0.002 f/cc. The concentrations of asbestos in all the samples were below 0.01 f/cc, emission limit for asbestos-removal facilities. The use of a wetting agent and the use of water were compared to analyze asbestos concentration in air during asbestos removal. According to the analysis, asbestos concentration was 0.002 f/cc on average with wetting agents and the concentration was 0.003 f/cc when water was used. The surface tension of wetting agents showed 28.9 to 42.1 mN/m range and the average was 34.9 mN/ m. The surface tension of tap water showed 72.2 mN/m. Water-absorption time was from 16 seconds to 300 seconds for wetting agents and the agents showed a significant difference with one another. Surface area on the roof tiles was measured by instillation of its spread. For wetting agents, the range was from 31.2 to 64.7 cm2, with the average of 40.6 cm2 and all wetting agents showed larger areas than tap water. Drying rate was measured for the assessment of wetting. According to the measurement, the rate ranged from 0.094 to 0.144 min-1 and 0.110 min-1 was the average. It was found that the drying rate of tap water was bigger than those of all the wetting agents, but some wetting agents did not show a big difference.

Anti-wetting surfaces with self-healing property: Fabrication strategy and application

Shuyue Jiang,Haifeng Zhang,Xiaowei Liu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.117 No.-

Anti-wetting surfaces (superhydrophobic and slippery liquid-infused surfaces) are of considerable currentinterest due to their unique abilities, addressing many vital technical problems such as icing of glass,corrosion of metal, surface contamination of fabric and treatment of oily wastewater. But the unsustainabilityof anti-wetting surfaces has severely hindered their industrial applications. Self-healing inspiredfrom plants and human skins can effectively enhance the longevity and durability of anti-wetting surfaces. However, the comprehensive investigation concerning the fabrication strategies of self-healinganti-wetting surfaces from the point of substrates is yet not obtained up to date. In this review, we summarizedthe fabrication strategies of self-healing anti-wetting surfaces on glass, metals, fabrics and polymers. Then the application of self-healing anti-wetting surfaces in the fields of anti-icing, anti-corrosion,anti-fouling and oil–water separation were comprehensively reviewed in detail. Finally, great challengesand further perspectives on the application of self-healing anti-wetting surfaces are presented.

Analysis of wetting properties of microstructured polymer surfaces to achieve superhydrophobic properties

Choi Ji Seong,Bae Min,Kang Seong Min 한국물리학회 2024 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.84 No.12

Superhydrophobic surfaces have gained signifcant research attention for various applications, such as self-cleaning and microfuidics. To develop superhydrophobic surfaces, diverse materials and structures are used to reduce the surface energy. Specifc coatings can control the intrinsic contact angle (CA) by reducing the surface energy of a material. In this study, we fabricated and evaluated polymeric superhydrophobic surfaces. The superhydrophobic surfaces exhibited microstructures consisting of two diferent polymers. To evaluate the wetting properties, we calculated the theoretical Cassie and Wenzel models of the surfaces and compared them to the experimental CA and roll-of angle (ROA). Furthermore, we measured the wetting properties of the surfaces by coating them with octafuorocyclobutane (C4F8) to confrm the efect of coating on the surfaces. This coated surface can control the wetting properties regardless of the material composition, demonstrating the stability of the superhydrophobic surface.

윤활액이 담지된 나노다공성 표면의 최신 응용분야

한경완(Kyeongwan Han),배기창(Kichang Bae),이정훈(Junghoon Lee) 한국표면공학회 2023 한국표면공학회지 Vol.56 No.1

Lubricant-impregnated nanoporous surfaces (LIS), which is created by impregnating water-immiscible oil into nanoporous surface structure, have been explored considering wide range of application fields. Due to the lubricant impregnated in nanoporous structure, the surface shows extreme de-wetting with a high mobility of water droplets, so that various functionalities can be realized. The lubricant layer inhibits the contact of corrosive media to porous structure as well as metal substrate, thus the surface improves the corrosion resistance. The water on the surface freeze without any contact to solid porous structure, showing a low ice adhesion for de-icing an anti-icing. The extremely high mobility of water droplets on lubricant-impregnated porous surfaces also contributes the enhancement of condensation heat transfer as well as water harvesting from fog and moisture. Moreover, the bacteria adhesion on metal surface forming biofilms causing serious hygiene issues can be inhibited on the lubricantimpregnated surfaces. Despite of such superior functionalities, the lubricant-impregnated porous surface has a limitation of lubricant depletion by external flow of fluids. Therefore, extensive efforts to improve the durability of lubricant-impregnated surface are required for practical applications.

Comparison of three different types of cilostazol-loaded solid dispersion: Physicochemical characterization and pharmacokinetics in rats

Mustapha, Omer,Kim, Kyung Soo,Shafique, Shumaila,Kim, Dong Shik,Jin, Sung Giu,Seo, Youn Gee,Youn, Yu Seok,Oh, Kyung Taek,Yong, Chul Soon,Kim, Jong Oh,Choi, Han-Gon Elsevier 2017 Colloids and surfaces Biointerfaces Vol.154 No.-

<P><B>Abstract</B></P> <P>The aim of this research was to compare three different types of cilostazol-loaded solid dispersion system including solvent-evaporated, solvent-wetted and surface-attached solid dispersion. The effect of polymers and surfactants on the aqueous solubility of cilostazol was investigated, leading to the selection of polyvinylpyrrolidone (PVP) and sodium lauryl sulphate (SLS). Employing a spray-drying technique, numerous surface-attached, solvent-evaporated and solvent-wetted solid dispersions were prepared with various amounts PVP and SLS using water, 90% ethanol and acetone, respectively. Their physicochemical properties, solubility, dissolution and oral bioavailability in rats were assessed compared to the drug powder. Among each solid dispersion system tested, the surface-attached, solvent-evaporated and solvent-wetted solid dispersions composed of cilostazol, PVP and SLS at weight ratios of 3.0 : 0.75 : 1.5, 3.0 : 3.0 : 1.5 and 3.0 : 3.0 : 1.5, respectively, provided the highest drug solubility and dissolution. The solvent-evaporated solid dispersion gave homogeneous and very small spherical particles, in which the drug was changed to an amorphous state. In the solvent-wetted solid dispersion, the amorphous drug was attached to the polymer surface. Conversely, in the surface-attached solid dispersion, the carriers were adhered onto the surface of the unchanged crystalline drug. The solubility, dissolution and oral bioavailability were significantly increased in the order of solvent-evaporated>solvent-wetted>surface-attached>drug powder. Thus, the type of solid dispersion considerably affected the physicochemical properties, aqueous solubility and oral bioavailability. Furthermore, the cilostazol-loaded solvent-evaporated solid dispersion with the highest oral bioavailability would be actively recommended as a practical oral pharmaceutical product.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cilostazol-loaded three different types of cilostazol-loaded solid dispersions were prepared. </LI> <LI> They were prepared with PVP, sodium laurylsulfate and different solvents using spray-drying techniques. </LI> <LI> The solvent-evaporated solid dispersion gave higher drug solubility and bioavailability than the others. </LI> <LI> These different types affected the physicochemical properties and oral bioavailability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

계면활성제 농도 변화에 따른 셀룰로오즈계 가연물에서의 표면흡수 동적 메커니즘에 관한 연구

김남균,임경범,이동호,Kim. Nam Kyun,Lim. Kyung Bum,Rie. Dong Ho 한국방재학회 2012 한국방재학회논문집 Vol.12 No.6

2005년 대구 서문시장 화재사건의 경우, 심부까지 소화용수가 침투되지 않아 화재 진압 후 재발화로 인해 2차 화재가 발생하여 대형화재로 이어졌다. 이와 같이 일반적인 소화용수를 사용하여 다량의 다공성 물질이 적재되어 있는 공간에서 발생한 화재를 진압하는 경우, 물질의 심부에서 진행되는 연소에 대한 소화 한계성을 가지며 재발화의 위험성이 존재한다. 그러나 현재 국내의 침윤소화약제 기술기준은 표면장력에 대한 기준만 존재하여 이를 통한 약제의 성능평가는 어려운 실정이다. 따라서 본 연구에서는 종이와 섬유에 대한 계면활성제의 농도에 따른 젖음 속도 및 젖음 면적을 측정하여 다공성 물질의 표면흡수특성을 파악하였다. 이를 통하여 계면활성제 첨가에 의한 표면장력의 저하에 따라 표면에서의 흡수성이 향상됨을 확인하였다. In the case of Seo-Moon market in Deagu (2005), fire relapse after fire suppression has led the accident to a large fire due to secondary fire occurred because the fire fighting water did not penetrate until deep place. Thus, in the case of using a common fire fighting water extinguish a fire in the place where a large amount of cellulosic combustibles is loaded, there is a risk of fire relapse and that has digestive limitations for a combustion in the deep of cellulosic combustibles. However, a standard exist only on the surface tension in the current domestic wetting agent technology standards, so it is difficult to the performance evaluation of the wetting agent through the standard. Therefore, in this study, surface absorption mechanism were studied by measuring that wetting speed and wetting area according to the concentration of the surfactant for cellulosic combustibles(the paper and textile). Through this study, Depending on the degradation of the surface tension by surfactant addition, it was confirmed that the absorptiveness is improved on the surface.

HEAT TRANSFER AND PRESSURE DROP CHARACTERISTICS OF FIN-AND-TUBE HEAT EXCHANGERS HAVING SPIRAL FINS UNDER WET CONDITIONS

이진욱,김내현,심현민 대한설비공학회 2011 International Journal Of Air-Conditioning and Refr Vol.19 No.3

In this study, wet surface j and f factors were obtained for spiral fin-and-tube heat exchangers. Nine samples having different fin pitches (2.12, 2.54 and 3.18 mm) and different tube rows (1, 2 and 3 row) were tested. Data are compared with those of the dry surface. For the wet surface, the effect of fin pitch on j factor is not significant. However, f factor decreases as the number of tube row increases. The j factor increases as the number of tube row increases. Different from the j factor, f factor decreases as the number of tube row increases. At one row configuration, the dry surface j factor is larger than that of the wet surface one. As the number of tube row increases, the trend is gradually reversed. Possible reasoning is provided considering the condensate behavior under wet condition. A new j and f factor correlation is developed, which predicts j and f factors within ± 20% and ± 30%, respectively.