Time filter

Source Type

Jhong J.-F.,Chung Yuan Christian University | Venault A.,Chung Yuan Christian University | Liu L.,University of Akron | Zheng J.,University of Akron | And 6 more authors.
ACS Applied Materials and Interfaces | Year: 2014

Herein, a pseudozwitterionic structure bearing moieties with mixed positive and negative charges is introduced to develop a potential biomaterial for wound dressing applications. New mixed-charge matrices were prepared by copolymerization of the negatively charged 3-sulfopropyl methacrylate (SA) and positively charged [2-(methacryloyloxy)ethyl] trimethylammonium (TMA) onto expanded polytetrafluoroethylene (ePTFE) membranes. The charge balance was effectively regulated through the control of the initial SA/TMA ratio. The focus was then laid on the assessment of a variety of essential properties of efficient wound dressings including, hydration property, resistance to fibrinogen adsorption, hemocompatibility, as well as resistance to fibroblast attachment and bacteria colonization. It was found that the pseudozwitterionic membranes, compared to those with charge bias in the poly(SA-co-TMA) structure, exhibited the best combination of major properties. Therefore, they were further tested for wound healing. Histological examination of mouse wound treated with the pseudozwitterionic membranes exhibited complete re-epithelialization and total formation of new connective tissues after 14 days, even leading to faster healing than using commercial dressing. Results presented in this work suggest that the mixed-charge copolymers with a perfect balance of positive and negative moieties represent the newest generation of biomaterials for wound dressings. © 2014 American Chemical Society.


Venault A.,Chung Yuan Christian University | Chang Y.,Chung Yuan Christian University | Hsu H.-H.,Chung Yuan Christian University | Jhong J.-F.,Chung Yuan Christian University | And 6 more authors.
Journal of Membrane Science | Year: 2013

In this work, the research focus is laid on the preparation of biofouling-resistant expanded poly(tetrafluoroethylene) (ePTFE) membranes via a facile process of atmospheric plasma-induced surface PEGylation. After surface coating of poly(ethylene glycol) methyl ether methacrylate (PEGMA), plasma-induced copolymerization was performed by a new atmospheric plasma treatment process over a short period ranging from 0 to 120s. Controllable grafting and growth of PEGylated copolymer segments with treatment time was ascertained by FT-IR, contact angle, surface roughness, and grafting yield analysis. The grafting yield was enhanced with the plasma treatment duration, evidencing a very good process control. The surface roughness increased until a 60s treatment time, before decreasing owed to saturation of surfaces with grafted copolymer and the obtaining of homogeneous PEGylated layer. The water contact angle dropped from 105±1° for the virgin membrane to 9±1° for the PEGylated ePTFE membrane obtained at a 120s plasma treatment, evidencing superhydrophilic surfaces. The PEGylated ePTFE membranes effectively reduced the adsorption of fibrinogen, a sticky protein, up to 18% the limitation of the virgin membrane. Bacterial attachment owed to Gram-positive bacteria (Staphylococcus epidermidis) and Gram-negative bacteria (Escherichia coli) was also effectively inhibited even after a 24h incubation time from a 60s treatment time, corresponding to a grafting yield of 0.10mg/cm2. This work suggests that the anti-baterial ePTFE membranes grafted with PEGylated layer in sufficient surface coverage, high hydration capability, and efficient grafting time via atmospheric plasma treatment present potential for use in membrane bioreactor applications, for which biofouling is a major issue. © 2013 Elsevier B.V.


Han C.C.,Chung Yuan Christian University | Lin Y.P.,Chung Yuan Christian University | Ho S.Y.,Chung Yuan Christian University | Lai Y.C.,Chung Yuan Christian University | And 3 more authors.
Journal of Physics D: Applied Physics | Year: 2010

In this study, the mesoporous anatase TiO2, TBF4, is synthesized by sol-gel polymerization using 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] as the template. The 450 °C-calcined TBF4 is found maintaining a mesoporous structure with a morphology that benefits dye adsorption and electrolyte diffusion. A series of dye-sensitized electrodes are prepared with a combination of the as-prepared TBF4 and P25, a commercial TiO2. It is found that the short-circuit photocurrent (Jsc) and open-circuit photovoltage (Voc) of the TBF4-containing electrodes are remarkably increased with the content of TBF4. The improvement is ascribed to an increase in the amount of dye molecules adsorbed and prolongation of the electron lifetimes (τeff). The highest light-to-electricity conversion efficiency (η) of the dye-sensitized solar cell is obtained from that prepared with the pure TBF4 electrode and is about 60% higher than that prepared with the pure P25 electrode under the same condition. © 2010 IOP Publishing Ltd.


Tung K.-L.,Chung Yuan Christian University | Li Y.-L.,Chung Yuan Christian University | Wang S.,Chung Yuan Christian University | Nanda D.,Chung Yuan Christian University | And 4 more authors.
Journal of Membrane Science | Year: 2010

A systematic study investigating the effect of membrane material and morphology on the filtration-cycle based on performance of three microfiltration membranes employed for filtering feed solution of Bovine Serum Albumin with yeast suspension has been carried out in dead-end filtration mode. The effects of operating conditions, like feed solution pH, transmembrane pressure (TMP), and membrane cleaning methods have been studied to establish a possible relationship with membrane fouling and to reduce the fouling that occurs during filtration. It was found that filtration resistance increases for the selected membranes with an increase in pH of the feed solution. An increase in TMP increases the permeate flux; however, the effect is not linear due to cake compression at higher TMP. The performance based on the filtration cycle is evaluated, and potential cleaning solutions to restore the permeate flux of filtration after several filtration cycles are identified. Scanning electron microscopy images demonstrate the experimental findings. The expanded polytetrafluoroethylene membrane flushed with caustic soda solution is found to be the most suitable and efficient membrane for microfiltration without significant reduction in flux and protein transmission, even after several filtration cycles. © 2010 Elsevier B.V. All rights reserved.


Jhong J.-F.,Chung Yuan Christian University | Venault A.,Chung Yuan Christian University | Hou C.-C.,Chung Yuan Christian University | Chen S.-H.,Chung Yuan Christian University | And 4 more authors.
ACS Applied Materials and Interfaces | Year: 2013

Development of bioinert membranes to prevent blood clotting, tissue adhesion, and bacterial attachment is important for the wound healing process. In this work, two wound-contacting membranes of expanded poly(tetrafluoroethylene) (ePTFE) grafted with zwitterionic poly(sulfobetaine methacrylate) (PSBMA) and hydrophilic poly(ethylene glycol) methacrylate (PEGMA) via atmospheric plasma-induced surface copolymerization were studied. The surface grafting chemical structure, hydrophilicity, and hydration capability of the membranes were determined to illustrate the correlations between bioadhesive properties and wound recovery of PEGylated and zwitterionic ePTFE membranes. Bioadhesive properties of the membranes were evaluated by the plasma protein adsorption, platelet activation, blood cell hemolysis, tissue cell adhesion, and bacterial attachment. It was found that the zwitterionic PSBMA-grafted ePTFE membrane presented high hydration capability and exhibited the best nonbioadhesive character in contact with protein solution, human blood, tissue cells, and bacterial medium. This work shows that zwitterionic membrane dressing provides a moist environment, essential for "deep" skin wound healing observed from the animal rat model in vivo and permits a complete recovery after 14 days, with histology of repaired skin similar to that of normal skin tissue. This work suggests that the bioinert nature of grafted PSBMA polymers obtained by controlling grafting structures gives them great potential in the molecular design of antibioadhesive membranes for use in skin tissue regeneration. © 2013 American Chemical Society.


Chuang C.-J.,Chung Yuan Christian University | Tung K.-L.,Chung Yuan Christian University | Fan Y.-H.,Chung Yuan Christian University | Ho C.-D.,Tamkang University | Huang J.,Yeu Ming Tai Chemical Industrial Co.
Water Science and Technology | Year: 2010

This paper reports experiments using a flat-sheet module with 0.18 ∼ 0.45 μm ePTFE (expanded polytetrafluoroethylene) and PVDF (polyvinylidene fluoride) membranes to show the effects of membrane properties, salt concentration and fluid hydrodynamics on the permeate flux and salt rejection of DCMD (direct contact membrane distillation). A theoretical prediction of the permeate flux was carried out, and was in close agreement with the experimental results. In addition, the energy integration of the process was also analyzed in order to evaluate module design to increase energy efficiency. According to the simulated results of the energy integration design, a combination of simultaneous cooling of the permeate stream and an additional heat exchanger to lower the temperature of the permeate stream not only enhances the MD flux, but also reduces energy consumption. © IWA Publishing 2010.


Patent
Yeu Ming Tai Chemical Industrial Co. | Date: 2011-03-02

The PTFE real twist yarn of the present invention is a PTFE real twist yarn (41) obtained by twisting a polytetrafluoroethylene (PTFE) multi-filament slit yarn. The yarn has a circular cross-section with a circularity in the range of 10/8 to 10/10, where the circularity is expressed by the ratio between the major axis width and the minor axis width, the average fineness of filaments (42) is in the range of 1.5 to 200 dtex, a fineness D is in the range of 50 to 6000 dtex, and a twist coefficient K expressed by Formula (1) is in the range of 10000 to 35000: where the number of twists T denotes the number of twists per meter and the fineness D is a total fineness.


Patent
Yeu Ming Tai Chemical Industrial Co. | Date: 2010-06-14

The PTFE real twist yarn of the present invention is a PTFE real twist yarn obtained by twisting a polytetrafluoroethylene (PTFE) multi-filament slit yarn. The yarn has a circular cross-section with a circularity in the range of 10/8 to 10/10, where the circularity is expressed by the ratio between the major axis width and the minor axis width, the average fineness of filaments is in the range of 1.5 to 200 dtex, a fineness D is in the range of 50 to 6000 dtex, and a twist coefficient K expressed by Formula (1) is in the range of 10000 to 35000: twist coefficient K=number of twists T(the fineness D of the PTFE real twist yarn)^(1/2)(1)

Loading Yeu Ming Tai Chemical Industrial Co. collaborators
Loading Yeu Ming Tai Chemical Industrial Co. collaborators