Browsing by Author "Lin, Han-Ching"

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Effect of an organically modified nanoclay on low-surface-energy materials of polybenzoxazine
(2008-07-16)
Fu, Huei-Kuan
;
Huang, Chih-Feng
;
Kuo, Shiao-Wei
;
Lin, Han-Ching
;
Yei, Ding-Ru
Novel low surface free energy materials of polybenzoxazine/organically modified silicate nanocomposites have been prepared and characterized. The CPC (cetylpyridinium chloride)/ claylo%/poly(3-phenyl-3,4-dihydro-2H-1,3-benzoxazine) (PP-a) material possesses an extremely low surface free energy (12.7 Mj. M-2) after 4 h curing at 200'C, which is even lower than that of poly(tetrafluoroethylene) (22.0 Mj. M-2) calculated on the basis of the threeliquid geometric method. X-Ray photoelectron spectroscopy (XPS) shows a higher silicon content on the surface of the nanocomposites than for an average composition, which implies that the clay is more preferentially enriched on the outermost layer. In addition, the glass transition temperature (Tg) of the polybenzoxazine (PP-a) in the nanocomposite is 22.6'C higher and its thermal decomposition temperature is also 31.5'C higher than the pure PP-a. This finding provides a simple way to prepare low surface energy and high thermal stability materials.
Effect of intermolecular hydrogen bonding on low-surface-energy material of poly(vinylphenol)
(2007-04-07)
Lin, Han-Ching
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Wang, Chih-Feng
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Kuo, Shiao-Wei
;
Tung, Pao-Hsiang
;
Huang, Chih-Feng
We discovered that poly(vinylphenol) (PVPh) possesses an extremely low surface energy (15.7 mJ/m(2)) after a simple thermal treatment procedure, even lower than that of poly(tetrafluoroethylene) ( 2.0 mJ/m(2)) calculated on the basis of the two-liquid geometric method. Infrared analyses indicate that the intermolecular hydrogen bonding of PVPh decreases by converting the hydroxyl group into a free hydroxyl and increasing intramolecular hydrogen bonding after thermal treatment. PVPh results in a lower surface energy because of the decrease of intermolecular hydrogen bonding between hydroxyl groups. In addition, we also compared surface energies of PVPh-co-PS (polystyrene) copolymers (random and block) and their corresponding blends. Again, these random copolymers possess a lower fraction of intermolecular hydrogen bonding and surface energy than the corresponding block copolymers or blends after similar thermal treatment. This finding provides a unique and easy method to prepare a low-surface-energy material through a simple thermal treatment procedure without using fluoro polymers or silicones.
Fabrication of Patterned Superhydrophobic Polybenzoxazine Hybrid Surfaces
(2009-03-17)
Liao, Chun-Syong
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Wang, Chih-Feng
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Lin, Han-Ching
;
Chou, Hsin-Yi
;
Chang, Feng-Chih
The hydrophilicity of bis(3-allyl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane(B-ala) polybenzoxazine film and superhydrophobic polybenzoxazine-hybrid surface can be controlled through UV exposure to change the ratio of intra to intermolecular hydrogen bonds. A fraction of the intramolecular hydrogen bonding of the as-cured sample will convert into intermolecular hydrogen bonding upon UV exposure and thus results in an increase of hydrophilicity. This simple method allows for manipulating the hydrophilicity at selected regions on a superhydrophobic polybenzoxazine hybrid surface to create a patterned surface with superhydrophobic and superhydrophilic regions. Additionally, we have found that the superhydrophobic polybenzoxazine-silica hybrid surface exhibits good adhesion of water droplets after UV exposure, which can be served as a "mechanical hand" to transfer water droplets from a superhydrophobic surface to a hydrophilic one.
Patterned Poly(2-hydroxyethyl methacrylate) Brushes on Silicon Surfaces Behave as "Tentacles" To Capture Ferritin from Aqueous Solution
(2009-07-01)
Chen, Jem-Kun
;
Chen, Zong-Yan
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Lin, Han-Ching
;
Hong, Po-Da
;
Chang, Feng-Chih
We have used a very large scale integration process to generate well-defined patterns of polymerized 2-hydroxyethyl methacrylate (HEMA) on patterned Si(100) surfaces. An atom transfer radical polymerization initiator covalently bonded to the patterned surface was employed for the graft polymerization of HEMA to prepare the poly(2-hydroxyethyl methacrylate) (PHEMA) brushes, After immersing wafers presenting lines of these polymers in water and cyclohexane, we observed brush- and mushroom-like regions, respectively. for the PHEMA brushes, with various pattern resolutions. The PHEMA brushes behaved as "tentacles" that captured ferritin complexes from aqueous solution through entanglement between the brushes and the Ferritin proteins, whose ferritins were trapped due to the collapsing of the PHEMA. Using high-resolution scanning electron microscopy, we observed patterned ferritin iron cores on the Si surface after thermal removal of the patterned PHEMA brushes and ferritin protein sheaths.
Preparation of the stimuli-responsive ZnS/PNIPAM hollow spheres
(2009-02-23)
Fu, Huei-Kuan
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Kuo, Shiao-Wei
;
Huang, Chih-Feng
;
Chang, Feng-Chih
;
Lin, Han-Ching
Novel quantum dots ZnS/poly(N-isopropylacrylamide) (PNIPAM) hybrid hollow spheres were obtained by localizing free radical polymerization of NIPAM and crosslinker (MBA) at the peripheral of PCL nanoparticles, followed by biodegradation of PCL with an enzyme of the Lipase PS. The formation of ZnS/PNIPAM hollow spherical structures and the thermo-sensitive reversible properties was systematically investigated by transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. The ZnS/PNIPAM hollow spheres possess the photoluminescence properties and a swelling and deswelling at about 32 degrees C, which agrees well with the slight red shift in photoluminescence spectra. (c) 2009 Elsevier Ltd. All rights reserved.
Tuning the Surface Free Energy of Polybenzoxazine Thin Films
(2008-10-01)
Liao, Chun-Syong
;
Wang, Chih-Feng
;
Lin, Han-Ching
;
Chou, Hsin-Yi
;
Chang, Feng-Chih
A novel approach to manipulate the surface free energy and wettability on polybenzoxazine thin films can be achieved simply by varying the time of thermal treatment or UV exposure. A fraction of the intramolecular hydrogen bonding of the as-cured sample will convert into intermolecular hydrogen bonding upon thermal treatment or UV exposure and, thus, results in an increase in the hydrophilicity and wettability. This UV approach provides a simple method to generate wettability patterns or wettability gradients on the surface of a polybenzoxazine film. In addition, we have applied this technique to the preparation of a large-area periodic array of CdTe colloidal nanocrystals on polybenzoxazine thin films.