Browsing by Author "Sheen, Yuung-Ching"

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New approach to fabricate an extremely super-amphiphobic surface based on fluorinated silica nanoparticles
(2008-09-15)
Sheen, Yuung-Ching
;
Huang, Yuan-Chang
;
Liao, Chun-Syong
;
Chou, Hisn-Yi
;
Chang, Feng-Chih
Superoleophobic surfaces possessing static contact angles greater than 140 degrees with organic liquids are extremely rare. A simple approach has been developed to fabricate an extremely superamphiphobic coating material based on fluorinated silica nanoparticles resulting contact angles of water and diiodomethane at 167.5 degrees and 158.6 degrees, respectively. The contact angle of diiodomethane at 158.6 degrees is substantially higher than the highest literature reported value we know of at 110 degrees. In addition, this developed film also possesses extremely high contact angles with other organic liquids such as soybean oil (146.6 degrees), decahysronaphthalene (142.5 degrees), diesel fuel (140.4 degrees), and xylene (140.5 degrees). This developed superamphiphobic organic-inorganic hybrid film possesses unique liquid repellency for both water and organic liquids that can be used as functional coatings on numerous substrates by a simple coating process. (C) 2008 Wiley Periodicals, Inc.
Non-fluorinated superamphiphobic surfaces through sol-gel processing of methyltriethoxysilane and tetraethoxysilane
(2009-03-15)
Sheen, Yuung-Ching
;
Chang, Wei-Hsuan
;
Chen, Wen-Chang
;
Chang, Yih-Her
;
Huang, Yuan-Chang
In this study, a simple approach was developed to fabricate an extremely superamphiphobic coating material by the tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) sol-gel derived materials. TEOS and MTES derived moieties were designed for a physical roughness and hydrophobic surface characteristic, respectively. The (29)Si solid-state NMR and ESCA analysis showed the coated silica composition was similar to the feeding ratios of TEOS/MTES. The surface structure characterized from SEM and TEM suggested the nanoparticle-based silica surface was observed at a high TEOS/MTES content but changed to a relatively smooth surface at a low TEOS content. The contact angles of water and CH(2)I(2) on the pure TEOS derived coated surface were both 0 degrees due to the hydrophilic Si-OH group. As the MTES composition increased to 25 mol% (T5M3), the coated surface had the contact angles of 149.8 degrees and 133.1 degrees for water and CH(2)I(2), respectively. It revealed that the T5M3-coated surface exhibited both super-hydrophobicity and super-oleophobicity, i.e., superamphiphobicity. Also, it had a relatively low-surface energy (1.38 mJ m(-2)) considerably lower than that of the F-silane-coated surface with 39.3 mJ m(-2). As the MTES composition increased further, both contact angles of water and CH(2)I(2) decreased. Especially, they decreased dramatically at the MTES feeding composition higher than 75 mol%, due to the much less rough surface at a higher MTES composition. The present study suggests that superamphiphobic surface could be achieved by non-fluorinated sol-gel derived silica materials. (C) 2008 Published by Elsevier B.V.
Stable superhydrophobic polybenzoxazine surfaces over a wide pH range
(2006-09-26)
Wang, Chih-Feng
;
Wang, Yi-Ting
;
Tung, Pao-Hsiang
;
Kuo, Shiao-Wei
;
Lin, Chun-Hung
In this study, we report on a simple two-step casting process designed to create a stable superhydrophobic surface. This method possesses the advantages of being both simple and inexpensive as well as utilizing non-fluorine-containing compounds. Most interestingly, we found that the as-prepared surface possesses superhydrophobic properties not only for pure water but also for corrosive water under both acidic and basic conditions. Furthermore, the superhydrophobic polybenzoxazine surfaces had excellent environmental stability with regard to both heating and organic solvent treatment in terms of the contact angle to water.
Synthesis and characterization of amorphous octakis-functionalized polyhedral oligomeric silsesquioxanes for polymer nanocomposites
(2008-08-26)
Sheen, Yuung-Ching
;
Lu, Chu-Hua
;
Huang, Chih-Feng
;
Kuo, Shiao-Wei
;
Chang, Feng-Chih
We have synthesized the polyhedral oligomeric silsesquioxane (POSS) derivatives OS-POSS and OA-POSS through the hydrosilylation of styrene and 4-acetoxystyrene, respectively, with octakis(dimethylsiloxy)-silsesquioxane (Q(8)M(8)(H)). We then prepared OP-POSS through acetoxyl hydrazinolysis of OA-POSS with hydrazine monohydrate. The chemical structures of these POSS derivatives were characterized using FTIR and H-1 NMR spectroscopy and MALDI-TOF mass spectrometry. Unlike Q(8)M(8)(H), which is crystalline, these three hydrosilylated POSS derivatives are liquids at 25 degrees C. Through DSC and XRD analyses, we found that they exhibit polymer-like glass transitions and amorphous halos. These octakis-functionalized POSS derivatives can be regarded as amorphous glasses possessing low glass transition temperatures, the values of which depend on the intermolecular interactions of their outer organic groups. To investigate the dispersion of these POSS derivatives in polymer nanocomposites, we blended OS-POSS, OA-POSS, and OP-POSS with polystyrene, poly(4-acetoxystyrene), and poly(4-vinylpyridine), respectively, and investigated the effects of the resulting intermolecular aromatic hydrophobic, dipole-dipole, and hydrogen-bonding interactions, respectively. Dipole-dipole interactions provided the best dispersion of OA-POSS in poly(4-acetoxystyrene), in which the POSS-polymer intermolecular interactions were of similar strength to the POSS-POSS interactions. (C) 2008 Elsevier Ltd. All rights reserved.
Thermal properties and surface energy characteristics of interpenetrating polyacrylate and polybenzoxazine networks
(2008-10-17)
Lu, Chu-Hua
;
Su, Yi-Che
;
Wang, Chih-Feng
;
Huang, Chih-Feng
;
Sheen, Yuung-Ching
We have prepared semi-interpenetrating polyacrylate networks (PA/BA-m s-IPNs) through rapid photo-polymerization of a triacrylate monomer (TMPTA) in the presence of a photomitiator (1184), a tetramercaptane transfer agent (4SH), and N-methyl-bisbenzoxazine (BA-m). Next, we prepared novel fully interpenetrating polyacrylate (PA) and polybenzoxazine (PBZ) networks (PA/PBZ f-IPNs) through thermal polymerization of the BA-m monomer at 180 degrees C for 4 h. For the PA/BA-m s-IPNs, the BA-m monomers can be frozen and dispersed in the UV-cured PA network within 5 min to inhibit macrophase separation. After thermal polymerization, the phenol units of the ring-opened PBZ segments can form a hydrogen-bonding interface with the carbonyl groups to improve the compatibility between the PBZ microdomains and the PA networks. From an analysis using Kissinger's method, the non-isothermal kinetics of the thermal polymerization for the PA/BA-m s-IPNs indicate that an increase in the PA content increased the steric hindrance of PBZ polymerization. We used DSC, TGA, and contact angle analyses to determine the glass transition temperature, thermal stability, and surface free energy, respectively, of the PA/PBZ f-IPNs. The thermal stability and surface free energy of these PA/PBZ f-IPNs display linear relationships with respect to the PBZ content. Crown Copyright (C) 2008 Published by Elsevier Ltd. All rights reserved.