Browsing by Author "Hwang, Bing-Joe"

Now showing 1 - 6 of 6

A new graphene-modified protic ionic liquid-based composite membrane for solid polymer electrolytes
(2011)
Ye, Yun-Sheng
;
Tseng, Chi-Yung
;
Shen, Wei-Chung
;
Wang, Jing-Shiuan
;
Chen, Kuan-Jung
The production of a solid polymer electrolyte with high ionic conductivity and mechanical properties is the main fabrication challenge in application of polymer electrolyte membranes. This paper describes a novel polymer electrolyte membrane using protic ionic liquids (PILs) with ionic liquid polymer modified graphene (G) sheets [denoted PIL(NTFSI)-G] that exhibit dramatic enhancements in ionic conductivity (257.4%) and mechanical properties (345% improvement in tensile strength and a near 25-fold increase in modulus were achieved at 150 degrees C) with a minimal loading of PIL(NTFSI)-G (0.5 wt %). The addition of graphene, by sparing the high-cost PIL addition, gives a 20% cost-saving. The homogeneous distribution of graphene sheets as a 3D network through the polymer matrix in the composite membrane provides a high degree of continuous and interconnected transfer channels to facilitate ion transfer and enhance nanofiller-matrix adhesion to reinforce mechanical properties. This newly developed material provides a potential route toward the design and fabrication of polymer electrolytes.
Effect of morphology of mesoporous silica on characterization of protic ionic liquid-based composite membranes
(2011-07-01)
Ye, Yun-Sheng
;
Liang, Gao-Wei
;
Chen, Bo-Han
;
Shen, Wei-Chung
;
Tseng, Chi-Yung
Effects caused by the morphology of mesoporous silica on the characterization of protic ionic liquid-based composite membranes for anhydrous proton exchange membrane applications are investigated. Two types of SBA15 materials with platelet and fiberlike morphologies are synthesized and incorporated into a mixture of polymerizable monomers together with an ionic liquid (IL)[1-butyl-3-methylimidazolium bis(trifluoromethane sulfone)imide (BMIm-TFSI)] to form new conducting membranes using an in situ photo crosslinking process. Incorporation of a defined amount of fiber-shaped SBA 15 and platelet 15 significantly increases the ionic conductivity to between two and three times that of a plain poly(methyl methacrylate) (PMMA)/IL membrane (2.3 mS cm(-1)) at 160 degrees C. The protic ionic liquid (PIL) retention ability of the membranes is increased by the capillary forces introduced by the mesoporous silica materials, while ionic conductivity loss after leaching test is retarded. The highest ionic conductivity (5.3 mS cm(-1)) is obtained by incorporating 5 wt% of P-SBA 15 in the membrane to about six times that of plain PMMA/IL membrane (0.9 mS cm(-1)) at 160 degrees C after leaching test. (C) 2011 Elsevier B.V. All rights reserved.
Fabrication of WO3 photoanode decorated with Au nanoplates and its enhanced photoelectrochemical properties
(2019-10-20)
Liu, Ying
;
Chang, Yung-Shan
;
Hsu, Yung-Jung
;
Hwang, Bing-Joe
;
Hsueh, Chun-Hway
In the present work, we improved the photoelectrochemical (PEC) performance of tungsten trioxide (WO3) photoanode by decorating WO3 plates with Au nanoplates. WO3 plates were fabricated on FTO-coated glass by hydrothermal treatment and Au nanoplates were incorporated by immersing the substrates in Au nanoplates solution under different periods of time. Our study revealed that compared with pristine WO3, the Au-WO3 nanocomposite performed enhanced photocurrent density under irradiation of the simulated sunlight. This improved PEC performance was benefited from the extension of light absorption resulting from the surface plasmon resonance effect of Au nanoplates at about 650 nm wavelength, and it was verified by UV-vis absorption spectra. The incident photon-to-current conversion efficiency measurements revealed improved photoactivity after decoration of WO3 with Au nanoplates. This study provided a facile method to decorate Au nanoplates on WO3 photoanodes with enhanced performance for solar energy conversion. (C) 2019 Elsevier Ltd. All rights reserved.
Synthesis and characterization of sulfonated polytriazole-clay proton exchange membrane by in situ polymerization and click reaction for direct methanol fuel cells
(2012-06-15)
Huang, Yao-Jheng
;
Ye, Yun-Sheng
;
Syu, Yu-Jyuan
;
Hwang, Bing-Joe
;
Chang, Feng-Chih
Sulfonated polytriazole-clay (SFTA-clay) nanocomposites are successfully prepared by in situ polymerization of SPTA using click chemistry in the presence of propargyl-functionality modified clay. The clay layers are exfoliated and well dispersed within the SPTA matrix resulting in improvements in thermal stability, mechanical strength, methanol permeability, water retention, ion channel size, and ionic cluster distribution. The SPTA-clay nanocomposite membranes with small amounts of clay in the SPTA matrices possess higher selectivity's; defined as the ratio of proton conductivity to methanol permeability, and thus have potential as proton exchange membranes (PEMs) in direct methanol fuel cells (DMFCs). (C) 2012 Elsevier B.V. All rights reserved.
Versatile Grafting Approaches to Functionalizing Individually Dispersed Graphene Nanosheets Using RAFT Polymerization and Click Chemistry
(1970-01-01)
Ye, Yun-Sheng
;
Chen, Yun-Nian
;
Wang, Jing-Shiuan
;
Rick, John
;
Huang, Yao-Jheng
"Developing powerful and reliable strategies to covalently functionalize graphene for efficient grafting and achieving precise interface control remains challenging due to the strong interlayer cohesive energy and the surface inertia of graphene. Here, we present versatile and efficient grafting strategies to functionalize graphene nanosheets. An alkyne-bearing graphene core was used to prepare polymer-functionalized graphene using 'grafting to' and 'grafting from' strategies in combination with reversible chain transfer and click chemistry. The use of the 'grafting to' approach allows full control over limited length grafted 0 polymer chains, while permitting a high grafting density to a single graphene face, resulting in good solubility and processability. The 'grafting from' approach offers complementary advantages, such as the grafting of high molecular weight polymer chains and a better coverage ratio on the graphene surface; however, the extra steps introduced, the presence of initiating groups, and difficulty in controlling the grafted polymer lead to decreased processability. Various types of polymer chains have been successful covalently tethered to graphene nanosheets using these two approaches, producing various molecular brushes with multifunctional arms resulting in water-soluble, oil-soluble, acidic, basic, polar, apolar, and variously functionalized polymers. This work describes versatile methodologies, using the 'grafting to' and 'grafting from' approaches, for the preparation of individually dispersed graphene nanosheets having the desirable properties described."
Versatile grafting approaches to star-shaped POSS-containing hybrid polymers using RAFT polymerization and click chemistry
(2011)
Ye, Yun-Sheng
;
Shen, Wei-Chung
;
Tseng, Chi-Yung
;
Rick, John
;
Huang, Yao-Jheng
An alkyne-bearing polyhedral oligomeric silsesquioxane (POSS) core was used to prepare POSS-containing polymer hybrids using 'grafting to' or 'grafting from' strategies in combination with reversible chain transfer and click chemistry.