Browsing by Author "Wang, Jui-Hsu"

Now showing 1 - 7 of 7

Block-copolymer-like supramolecules confined in nanolamellae
(2012)
Wang, Jui-Hsu
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Cheng, Chih-Chia
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Yen, Ying-Chieh
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Miao, Chia-Chun
;
Chang, Feng-Chih
This paper describes the development of a new concept in supra-molecular assembly of existing functional polypeptides to form diblock-like molecular clusters through complementary hydrogen-bonding interactions, providing a potential route toward design and fabrication of block copolymer-like supramolecular materials.
Dynamic supramolecular self-assembly: hydrogen bonding-induced contraction and extension of functional polymers
(2017-06-07)
Cheng, Chih-Chia
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Wang, Jui-Hsu
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Chuang, Wei-Tsung
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Liao, Zhi-Sheng
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Huang, Jyun-Jie
Simple construction and manipulation of low-molecular-weight supramolecular polymers, based on incorporation of self-complementary multiple hydrogen bonding interactions, with the desired dynamic response characteristics to achieve high-efficiency supramolecular assembly and control the morphological properties of the polymers remain highly challenging. Herein, we developed a new difunctional tele-chelic supramolecular polymer (UrCy-PPG) containing self-complementary quadruple hydrogen-bonded ureido-cytosine (UrCy) moieties, which spontaneously self-assembles to form long-range-ordered lamellar structures in the bulk state. Scattering and rheological studies confirmed that the dynamic behavior of UrCy units induces structural phase transitions from quadruple to dual hydrogen-bonded arrays, leading to well-controlled, self-organized supramolecular nanostructure morphologies. The microstructural features could be easily tuned by altering environmental conditions, making the self-assembly processes highly efficient. Importantly, temperature/shear stress-dependent microstructural analyses indicated that UrCy-PPG has the capacity to manipulate the transition between contractile and fully extended lamellar structures. Given its novelty, simple synthesis, high reliability, and efficient self-assembly processes, this newly developed supramolecular polymer represents a new concept and pathway for controlled arrangement of self-assembled polymeric nanostructures.
Functionalized graphene nanomaterials: new insight into direct exfoliation of graphite with supramolecular polymers
(2016-01-01)
Cheng, Chih-Chia
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Chang, Feng-Chih
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Wang, Jui-Hsu
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Chen, Jem-Kun
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Yen, Ying-Chieh
A novel urea-cytosine end-capped polypropylene glycol (UrCy-PPG) can self-assemble into a long-range ordered lamellar microstructure on the surface of graphene, due to the strong specific interactions between UrCy-PPG and graphene. In addition, the graphene composite produced exhibits a high conductivity (similar to 1093 S m(-1)) with a dramatic thermo-responsive ON/OFF resistance-switching behavior (10 consecutive cycles).
Large-scale production of ureido-cytosine based supramolecular polymers with well-controlled hierarchical nanostructures
(2015-01-01)
Cheng, Chih-Chia
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Chang, Feng-Chih
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Wang, Jui-Hsu
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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.
Star Block Copolymers Through Nitroxide-Mediated Radical Polymerization From Polyhedral Oligomeric Silsesquioxane (POSS) Core
(2010-06-15)
Lu, Chu-Hua
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Wang, Jui-Hsu
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Chang, Feng-Chih
;
Kuo, Shiao-Wei
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應用化學系
A series of star block copolymers were prepared through nitroxide-mediated radical polymerization (NMRP) from polyhedral oligomeric silsesquioxanes (POSS) nanoparticle by core-first polymerization. Eight N-alkoxyamine groups were incorporated onto the eight corners of a POSS cube through quantitative hydrosilylation through addition of octakis(dimethylsiloxy)silsesquioxane (O(8)M(8)(H) POSS) with 1-(2-(allyloxy)-1-phenylethoxy)-2,2,6,6-tetramethyl-piperidine (allyl-TEMPO) and Karstedt's agent (a platinum divinylsiloxane complex) was used as a catalyst. Octa-N-alkoxyamines POSS (OT-POSS) were used as platform to synthesize star polystyrene-POSS ((PS)(8)-POSS) homopolymer and diblock copolymers of poly(styrene-block-4-vinyl-pyridine)-POSS ((PS-b-P4VP)(8)-POSS) and poly(styrene-block-acetoxystyrene) ((PS-b-PAS)(8)-POSS) through NMRP. In addition, subsequent selective hydrolysis of the acetyl protective group of (PS-b-PAS)(8)-POSS, the poly(styrene-block-vinyl phenol) ((PS-b-PVPh)(8)-POSS) with strong hydrogen bonding group was obtained. The detailed chemical structure and self-assembled structures of these star block copolymers based on POSS were characterized by (1)H NMR, FTIR, SEC, TEM, and SAXS analyses.
Supramolecular Functionalities Influence the Thermal Properties, Interactions and Conductivity Behavior of Poly(ethylene glycol)/LiAsF6 Blends
(2013-09-01)
Wang, Jui-Hsu
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Cheng, Chih-Chia
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Altukhov, Oleksii
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Chang, Feng-Chih
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Kuo, Shiao-Wei
In this study, we tethered terminal uracil groups onto short-chain poly(ethylene glycol) (PEG) to form the polymers, uracil (U)-PEG and U-PEG-U. Through AC impedance measurements, we found that the conductivities of these polymers increased upon increasing the content of the lithium salt, LiAsF6, until the Li-to-PEG ratio reached 1:4, with the conductivities of the LiAsF6/U-PEG blends being greater than those of the LiAsF6/U-PEG-U blends. The ionic conductivity of the LiAsF6/U-PEG system reached as high as 7.81 x 10(-4) S/cm at 30 degrees C. Differential scanning calorimetry, wide-angle X-ray scattering, Li-7 nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy revealed that the presence of the uracil groups in the solid state electrolytes had a critical role in tuning the glass transition temperatures and facilitating the transfer of Li+ ions.
Supramolecular structures of uracil-functionalized PEG with multi-diamidopyridine POSS through complementary hydrogen bonding interactions
(2013)
Wang, Jui-Hsu
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Altukhov, Oleksii
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Cheng, Chih-Chia
;
Chang, Feng-Chih
;
Kuo, Shiao-Wei
In this study, we synthesized (i) a multi-diamidopyridine-functionalized polyhedral oligomeric silsesquioxane (MD-POSS) through nucleophilic substitution and click 1,3-cycloaddition reactions and (ii) both mono- and bis-uracil (U)-functionalized poly(ethylene glycol) derivatives (U-PEG and U-PEG-U, respectively) through Michael additions of U to acryloyl-functionalized PEG oligomers. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) revealed that supramolecular structures self-assembled from mixtures of MD-POSS and U-PEG and from MD-POSS and U-PEG-U. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy confirmed the presence of multiple hydrogen bonding interactions between the diaminopyridine groups of MD-POSS and the U groups of U-PEG and U-PEG-U. Because of these strong reversible intermolecular multiple hydrogen bonds, the POSS-based polymer-like supramolecular materials exhibited improved thermal properties upon increasing the MD-POSS content.