Browsing by Author "Tung, Pao-Hsaing"

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Hydrogen bond mediated supramolecular micellization of diblock copolymer mixture in common solvents
(2009-07-01)
Kuo, Shiao-Wei
;
Tung, Pao-Hsaing
;
Chang, Feng-Chih
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應用化學系
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Department of Applied Chemistry
We report a new approach toward preparing self-assembled hydrogen-bonded complexes having vesicle and patched spherical structures from two species of block copolymers in nonselective solvents. Two diblock copolymers, poly(styrene-b-vinyl phenol) (PS-b-PvPh) and poly(methyl methacrylate-b-4-vinylpyridine) (PMMA-b-P4VP), were synthesized through anionic polymerization. The assembly of vesicles from the intermolecular complex formed after mixing PS-b-PVPH with PMMA-b-P4VP in THF was driven by strong hydrogen bonding between the complementary binding sites on the PVPH and P4VP blocks. In contrast, well-defined patched spherical micelles formed after blending PS-b-PVPh with PMMA-b-P4VP in DMF: the weaker hydrogen bonds formed between the PVPh and P4VP blocks in DMF, relative to those in THF, resulted in the formation of spherical micelles having compartmentalized coronas consisting of PS and PMMA blocks. (C) 2009 Elsevier Ltd. All rights reserved.
Micellization and the surface hydrophobicity of amphiphilic poly(vinylphenol)-block-polystyrene block copolymers
(2007-08-20)
Tung, Pao-Hsaing
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Kuo, Shiao-Wei
;
Chan, Shih-Chien
;
Hsu, Chih-Hao
;
Wang, Chih-Feng
The self-assembly of PVPh-b-PS in different solvents was studied. Upon replacing toluene by THF as the solvent, the morphology of the resulting aggregates change from core-shell spheres, rod-like micelles and vesicles to onion-like aggregates. With increasing block copolymer concentration, morphologies such as honeycomb-like films, surfaces of aggregated large porous spheres, or pincushion-like spheres with protruding tubular vesicle aggregates are observed. These surface-patterned films show significantly enhanced hydrophobicity. The results suggest that a superhydrophobic . behavior can be achieved, with a maximum contact angle of 158 degrees, by using the pincushion-like micellar structure.
Regular honeycomb porous polymer films based on amphiphilic block copolymer
(2006-11-20)
Tung, Pao-Hsaing
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Huang, Chih-Feng
;
Chen, Shih-Chien
;
Hsu, Chih-Hao
;
Chang, Feng-Chih
Supramolecular micellization of diblock copolymer mixtures mediated by hydrogen bonding for the observation of separated coil and chain aggregation in common solvents
(2008-02-01)
Kuo, Shiao-Wei
;
Tung, Pao-Hsaing
;
Lai, Chih-Ling
;
Jeong, Kwang-Un
;
Chang, Feng-Chih
This paper describes a new approach towards preparing self-assembled hydrogen-bonded complexes that have vesicle and patched spherical structures from two species of block copolymer in non-selective solvents. The assembly of vesicles from the intermolecular complex formed after mixing polystyrene-block-poly(4-vinyl phenol) (PS-b-PVPh) with poly(methyl methacrylate)-block-poly(4-vinylpyridine) (PMMA-b-P4VP) in tetrahydrofuran (THF) is driven by strong hydrogen bonding between the complementary binding sites on the PVPh and P4VP blocks. In contrast, well-defined patched spherical micelles form after blending PS-b-PVPh with weaker hydrogen bonds form between the PVPh and P4VP blocks in DMF, relative to those in THF, which results in the formation of spherical micelles that have compartmentalized coronas that consist of PS and PMMA blocks.