Browsing by Author "Wang, Yeh-Sheng"

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Bioinspired Photo-Cross-Linked Nanofibers from Uracil-Functionalized Polymers
(2012-01-01)
Wang, Yeh-Sheng
;
Cheng, Chih-Chia
;
Ye, Yun-Sheng
;
Yen, Ying-Chieh
;
Chang, Feng-Chih
In this study, we used electrospinning to fabricate nucleobase-functionalized and photo-cross-linkable poly[1-(4-vinylbenzyl uracil)] (PVBU) nanofibers. PVBU of high-molecular-weight (M-n > 250 550 g/mol) possessed a high thermal stability and sufficient chain entanglement to produce uniform fibers without forming beads. These uracil-functionalized nanofibers were further photo-cross-linked through exposure to UV light at a wavelength of 254 nm. After immersing in N,N-dimethylacetamide, the pristine PVBU fibers dissolved, while the cross-linked PVBU fibers maintained their shape; thus, the cross-linked PVBU nanofibers exhibited good dimensional stability and improved solvent resistance.
Bioinspired supramolecular fibers for mercury ion adsorption
(2013)
Wang, Yeh-Sheng
;
Cheng, Chih-Chia
;
Chen, Jem-Kun
;
Ko, Fu-Hsiang
;
Chang, Feng-Chih
Anovel photo-cross-linkable nanofiber based on a uracil-functionalized polymer, poly[ 1-(4-vinylbenzyl uracil)] (PVBU), was prepared using the electrospinning technique. This PVBU nanofiber can be converted into a covalent network nanofiber through exposure to UV light at a wavelength of 254 nm. This PVBU nanofiber is able to distinguish and selectively remove mercury ions (Hg2+) from other metal ions in aqueous solution. The maximum Hg2+ adsorption capacity of the PVBU nanofiber is 543.9 mg g(-1), which is significantly higher than that of cyclic imide derivatives. The improved adsorption of Hg2+ allows a detection limit of less than 1 ppm, which has rarely been achieved for Hg2+ sensing. Furthermore, the PVBU fiber can be reused for 10 consecutive cycles using 1.0 M HCl treatment. This new material has significant potential for the simultaneous detection and separation of Hg2+ in environmental and industrial fields.
Large-scale production of ureido-cytosine based supramolecular polymers with well-controlled hierarchical nanostructures
(2015-01-01)
Cheng, Chih-Chia
;
Chang, Feng-Chih
;
Wang, Jui-Hsu
;
Chu, Yu-Lin
;
Wang, Yeh-Sheng
A novel supramolecular polymer containing urea-cytosine (UrCy) quadruple hydrogen-bonding moieties that possesses a high association constant (K-a > 10(6) M-1) was synthesized at high yield (96%) at kilogram-scale. The synthesized telechelic macromer dissolved in solution can undergo a substantial change in solution viscoelasticity and can self-assemble due to the noncovalent nature of supramolecular polymerization. As the concentration of UrCy in solution was increased, the spherical assemblies gradually transformed to an ordered lamellar phase with an extremely high degree of polymerization. In addition, the dynamic behavior of UrCy units induced a sudden phase transition in the bulk state, revealing an interesting order-disorder transition from a crystalline solid to liquid state. This newly-discovered material has excellent polymer-like features that are distinct to existing systems. A simple path for forming supramolecular polymers is recommended for the design, large-scale production and manipulation of self-assembled materials with distinctive properties.
Molecular recognition within a poly(amide urethane) system
(1970-01-01)
Yen, Ying-Chieh
;
Cheng, Chih-Chia
;
Tsai, Jia-You
;
Lin, I-Hong
;
Wang, Yeh-Sheng
"The heterodimer recognition within a poly(amide urethane) (PAU) has been achieved through the incorporation of the amphiphilic alkylated nucleobase, 1-hexadecyluracil (U16). The heterodimer recognition led the poly(amide urethane) to exhibit the ""plug and play"" behavior even the heterodimer recognition coincided with several other hydrogen bonding motifs. In addition, the PAU/U16 blends possess nano-scale lamellar structure of U16 phase within lamellar structure of PAU phase. The nano-scale lamellar structure of the packed U16 gradually transforms from one to the other with the change in the U16 content in the blends. (C) 2012 Elsevier Ltd. All rights reserved."
Supramolecular assembly-induced enhanced emission of electrospun nanofibers
(2015-01-01)
Cheng, Chih-Chia
;
Wang, Yeh-Sheng
;
Chang, Feng-Chih
;
Lee, Duu-Jong
;
Yang, Li-Chih
A nucleobase-assembled supramolecular nanofiber is capable of forming network-like polymeric clusters through complementary hydrogen-bonding interactions. It behaves as an effective chromophore that greatly enhances the light emission efficiency of fluorescent fibers, reaching up to three times higher efficiency than the control samples.
Supramolecular electrospun nanofibers with high conductivity at ultra-low carbon nanotube content
(2016)
Cheng, Chih-Chia
;
Wang, Yeh-Sheng
;
Chen, Jem-Kun
;
Lee, Duu-Jong
;
應用化學系
Complementary supramolecular polymers can efficiently control the arrangement of carbon nanotubes (CNTs) in electrospun nanofibers as a means of manipulating the conductivity pathways of CNTs, thus providing a new route to the fabrication of high-performance supramolecular nanofibers with superior electrical conductivity at ultra-low CNT content.
Surface modification of poly(2-methoxy-5-(2 '-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) by confined photo-catalytic oxidation
(2012-02-15)
Yen, Ying-Chieh
;
Cheng, Chih-Chia
;
Wang, Yeh-Sheng
;
Chu, Yu-Lin
;
Lu, Chu-Hua
In this study, the surface of pi-conjugated polymer, poly(2-methoxy-5(2'-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV), was successfully modified with the sulfate anion (SO4-) groups by the confined photo-catalytic oxidation (CPO). After the surface modification, the water contact angle of MEH-PPV is changed from 95.5 degrees to 82.1 degrees without influence on its optical properties (based on the UV and PL spectra), and the water droplet can be absorbed on the modified MEH-PPV surface without sliding even at substrate tilt angles of 90 degrees and 180 degrees. The CPO on the MEH-PPV surface is able to further expand the use of MEH-PPV for applications. In addition, the water transport test indicates that the modified MEH-PPV can be a candidate for transporting water droplet. (C) 2011 Elsevier Inc. All rights reserved.