學術出版;;Publications

Permanent URI for this communityhdl:11536/1

收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

Browse

🏛️國立陽明交通大學機構典藏

Search Results

Now showing 1 - 8 of 8

Phase behaviour and Janus hierarchical supramolecular structures based on asymmetric tapered bisamide
(2012)
Sun, Hao-Jan
;
Wang, Chien-Lung
;
Hsieh, I-Fan
;
Hsu, Chih-Hao
;
Van Horn, Ryan M.
A precisely defined molecular Janus compound based on asymmetric tapered 1,4-bis[3,4,5-tris(alkan-1-yloxy) benzamido] benzene bisamide (abbreviated as C(22)PhBAEO(3)) was designed and synthesized, and its phase behavior was fully investigated. The C(22)PhBAEO(3) compound possesses a rigid core with three aromatic rings connected with amide bonds which possess the ability to form hydrogen (H) bonds. Three hydrophobic alkyl flexible tails and three hydrophilic flexible methyl terminated triethylene glycol tails are located at the other end. Major phase transitions and their origins in C(22)PhBAEO(3) were studied via DSC and 1D WAXD techniques. Its hierarchical supramolecular crystal structure was further identified through combined techniques of 2D WAXD and SAXS as well as SAED. Results based on computer simulations confirmed the structure determination. It was found that the C(22)PhBAEO(3) possesses three phases through various thermal treatments including a micro-phase separated columnar liquid crystal (col.) phase, a metastable crystal I phase and a stable crystal II phase. Among them, the crystal II phase showed that the columnar structure possesses 3D inter-column order and highly crystalline alkyl tails with a long-range overall orientational order. Four C(22)PhBAEO(3) molecules self-assembled into a phase-separated disc with an ellipsoidal shape having a C-2 symmetry along the disc normal. These discs then stacked on top of each other to generate a 1D asymmetric column through H-bonding, and further packed into a 3D long-range ordered monoclinic lattice. The unit cell parameters of this lattice were determined to be a = 5.08 nm, b = 2.41 nm, c = 0.98 nm, alpha = 90 degrees, beta = 90 degrees, and gamma = 70.5 degrees. The alkyl chain tails crystallize within the hydrophobic layers and possess a relatively fixed orientation with respect to the column packing due to the selective interactions based on the hydrophobic/hydrophilic microphase separation. Both phase behaviour and unit cell structure showed significant difference compared with the symmetrically tapered counterparts. The results provided a new approach of fine-tuning not only in the Janus supramolecular structures but also in the formation pathway of the self-assembling process in order to meet the specific requirements for optical and biological applications.
Syntheses and specific interactions of poly(epsilon-caprolactone)-block-poly(vinyl phenol) copolymers obtained via a combination of ring-opening and atom-transfer radical polymerizations
(2006-11-01)
Kuo, Shiao-Wei
;
Huang, Chih-Feng
;
Lu, Chu-Hua
;
Lin, Ho-May
;
Jeong, Kwang-Un
A series of PCL-b-PVPh diblock copolymers were prepared through combinations of ring-opening and atom-transfer radical polymerizations of c-caprolactone and 4-acetoxystyrene, and subsequent selective hydrolysis of the acetyl protective group. This PCL-b-PVPh diblock copolymer shows a single glass transition temperature over the entire composition range, indicating that this copolymer is able to form a miscible amorphous phase due to the formation of intermolecular hydrogen bonding between the hydroxyl of PVPh and the carbonyl of PCL. In addition, DSC analyses also indicated that the PCL-b-PVPh diblock copolymers have higher glass transition temperatures than their corresponding PCL/PVPh blends. FT-IR was used to study the hydrogen-bonding interaction between the PVPh hydroxyl group and the PCL carbonyl group at various compositions.
Formation of honeycomb structures and superhydrophobic surfaces by casting a block copolymer from selective solvent mixtures
(2007-02-02)
Tung, Pao-Hsiang
;
Kuo, Shiao-Wei
;
Jeong, Kwang-Un
;
Cheng, Stephen Z. D.
;
Huang, Chih-Feng
Poly(vinyl phE!nol)-block-polystyrene (PVPh-b-PS) diblock copolymers are synthesized by sequential anionic polymerization with sec-butyl lithium as the initiator. The Pvph-b-PS diblock copolymer is cast (on a substrate) from several solvent mixtures that contain tetrahydrofuran/toluene ratios of 1:0.1, 1:1, and 1:2. After solvent evaporation the resulting films are characterized by SEM, TEM, and contact angle measurements. A honeycomb structure is fabricated from the vesicle structure at relatively low toluene contents. On the contrary, at relatively higIier toluene contents, a micelle structure with porous microspheres is formed, which possesses higher surface roughness and results in film surface superhydrophobicity. The simple method described here that uses common/selective mixed solvents may be easily extended to prepare honeycomb structures and superhydrophobic surfaces simultaneously from a wide variety of block copolymers by carefully controlling the weight composition of the block copolymer and the selective solvent con-tent.
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.
Substituent-induced delocalization effects on hydrogen-bonding interaction in poly(N-phenyl methacrylamide) derivatives
(2011-05-26)
Kuo, Shiao-Wei
;
Lin, Chien-Ting
;
Chen, Jem-Kun
;
Ko, Fu-Hsiang
;
Chang, Feng-Chih
Within small molecules, the hydrogen-bonding behaviors affected by delocalization have been studied thoroughly, but rare publication in macromolecules. Therefore, three poly(N-phenyl methacrylamide)s, poly(N-phenyl methacrylamide) (PNPAA), poly(N-4-methoxyphenyl methacrylamide) (PMPMA) and poly(N-4-bromophenyl methacrylamide) (PBPMA), with different inductive substitution at para position of benzene ring are prepared to investigate the substituent-induced delocalization effects on the hydrogen-bonding interaction behaviors. In this study, the variable-temperature FTIR spectrum is used as tool to study the self- and inter-association hydrogen-bonding interaction. FTIR analyses could provide evidences that there is relatively stronger inter-associative hydrogen bonding in poly(N-4-bromophenyl methacrylamide)/P4VP blends. High resolution (13)C CP/MAS solid-state NMR analyses indicate that the spin-lattice relaxation time (T) in all PBPMA blends are homogeneous on the scale at which spin-diffusion occurs within the time T(1)rho(H), also due to the enhancement by substituent inductive delocalization. (C) 2011 Elsevier Ltd. All rights reserved.
Self-assembly behavior and photoluminescence property of bispyrenyl-POSS nanoparticle hybrid
(2011-06-01)
Lu, Chu-Hua
;
Tsai, Chia-Hua
;
Chang, Feng-Chih
;
Jeong, Kwang-Un
;
Kuo, Shiao-Wei
Two flexible ether bonds were designed to connect two pyrene rings on a polyhedral oligomeric silsesquioxane (BPy-POSS) to enrich the fraction of "intrinsic intramolecular pyrene-dimer" on the surface of crystal isobutyl-POSS (iBu-POSS) thin-films. Compared to the monomer emission of 1-pyrenemethanol (Py-OH), the emission spectra of BPy-POSS in dichloromethane show the large proportion of intramolecular and intermolecular excimers due to the formation of pyrenyl dimers or aggregates via the easy rotation of two adjacent ether bonds and the pi-pi interaction of pyrene rings, respectively. By blending inert iBu-POSS, the fluorescent dimers or aggregates of 5 wt.% and 20 wt.% BPy-POSS are distributed on the surface of iBu-POSS crystal fractal pattern as shown by confocal photoluminescence microscopy. Upon exposure to the vapors of nitrobenzene, the 5 wt.% BPy-POSS blend shows the similar quenching efficiency as 100 wt.% BPy-POSS blends, indicating the better excimer dispersion for vapor permeability of blend thin-films. (c) 2011 Elsevier Inc. All rights reserved.
A Simple Route from Monomeric Nanofibers to Zinc Oxide/Zinc Sulfide Nanoparticle/Polymer Composites through the Combined Use of gamma-irradiation Polymerization, Gas/Solid Reaction and Thermal Decomposition
(2008-10-01)
Kuo, Shiao-Wei
;
Chung, Yao-Chu
;
Jeong, Kwang-Un
;
Chang, Feng-Chih
;
應用化學系
We report a simple route to hierarchical zinc oxide/zinc sulfide (ZnO/ZnS) nanoparticle/polymer nanofiber structures through self-assembly of zinc dimethacrylate (Zn(MA)(2)) in water/ethanol solution. The water clusters in formed around Zn(MA)(2) would undergo hydrogen-bonding interactions to create a supramolecular structure and then form the construction of three-dimensional nanofibers and random networks. These monomeric Zn(MA)(2) nanofibers are converted into ZnO or ZnS nanoparticle/polymer nanofiber composites through a combination of gamma-irradiated polymerizations and in situ thermal decomposition or H2S gas/solid reactions, respectively. The carboxylic ion groups of P-Zn(MA)(2) remained bonded to zinc ions on the particles' surfaces after thermal decomposition or the reaction with H2S. The compact polymer network prevented the ZnO or ZnS nanoparticles from aggregating to eliminate the defects. High-resolution transmission electron microscopes indicate that ZnO and ZnS particles are highly crystallized with a size of 3-7 nm. This is a simple approach to produce nanoparticle in polymer nanofibers. This preparation method can potentially be extended to other polymer matrices containing different metal ions.
Solid State and Solution Self-Assembly of Helical Polypeptides Tethered to Polyhedral Oligomeric Silsesquioxanes
(2009-03-10)
Kuo, Shiao-Wei
;
Lee, Hsin-Fang
;
Huang, Wu-Jang
;
Jeong, Kwang-Un
;
Chang, Feng-Chih
New macromolecular self-assembling building blocks, polyhedral oligo- silsesquioxane (POSS)-helical polypeptide copolymers, have been synthesized through the ring-opening polymerization (ROP) of gamma-benzyl-L-glutamate N-carboxyanhydride (gamma-Bn-Glu NCA) using aminopropyl isobutyl-POSS as a macroinitiator. The incorporation of POSS units at the chain ends of PBLG moieties has two important effects: allowing intramolecular hydrogen bonding between the POSS and PBLG units to enhance the latter's a-helical conformations in the solid state and preventing the aggregation of nanoribbons through the POSS blocks' protrusion from the ribbons to allow the formation of clear gels in solution.

學術出版;;Publications

Browse

Filters

Settings

Sort By

Results per page

🏛️國立陽明交通大學機構典藏

Search Results