Browsing by Author "Xin, Zhong"

Now showing 1 - 4 of 4

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.
New bioinspired hole injection/transport materials for highly efficient solution-processed phosphorescent organic light-emitting diodes
(2015-04-01)
Cheng, Chih-Chia
;
Chu, Yu-Lin
;
Chang, Feng-Chih
;
Lee, Duu-Jong
;
Yen, Ying-Chieh
A new concept to supramolecular assembly of existed functional polymers, capable of forming network-like organizational clusters through multiple hydrogen-bonding interactions has been exploited. In this paper, a new adenine-based poly(triphenylamine-carbazole) (PTC-A) has been prepared which exhibits a high self-complementary ability in solution and solid states owing to the formation of adenine-adenine (A-A) pairs by induced hierarchical self-assembly. Comparing with uracil-substituted PTC sample (PTC-U), PTC-A presents a much higher thermal stability, electrochemical stability and solvent-resistance ability due to the formation of the more stable physically cross-linking structure. When the PTC-A is utilized as a hole injection/transport layer in a trilayer OLED device, a remarkable improvement in performance relative to the control PTC and PTC-U under similar experimental conditions has been achieved. Further comparison with a control device using a conventional PEDOT:PSS, the efficiency of the solution-processed phosphorescent PLED device with PTC-A is significantly higher than those of PTC-U and PEDOT: PSS-based devices. Thus, PTC-A represents the next-generation hole injection/transport material for high efficiency LED device and low-cost fabrication process. (C) 2015 Elsevier Ltd. All rights reserved.
Nucleobase-Functionalized Supramolecular Micelles with Tunable Physical Properties for Efficient Controlled Drug Release
(2016-10)
Cheng, Chih-Chia
;
Lin, I-Hong
;
Chen, Jem-Kun
;
Liao, Zhi-Sheng
;
Huang, Jyun-Jie
Complementary nucleobase-functionalized polymeric micelles, a combination of adenine-thymine (A-U) base pairs and a blend of hydrophilic-hydrophobic polymer pairs, can be used to construct 3D supramolecular polymer networks; these micelles exhibit excellent self-assembly ability in aqueous solution, rapid pH-responsiveness, high drug loading capacity, and triggerable drug release. In this study, a multi-uracil functionalized poly(epsilon-caprolactone) (U-PCL) and adenine end-capped difunctional oligomeric poly(ethylene glycol) (BA-PEG) are successfully developed and show high affinity and specific recognition in solution owing to dynamically reversible A-U-induced formation of physical cross-links. The U-PCL/BA-PEG blend system produces supramolecular micelles that can be readily adjusted to provide the desired critical micellization concentration, particle size, and stability. Importantly, in vitro release studies show that doxorubicin (DOX)-loaded micelles exhibit excellent DOX-encapsulated stability under physiological conditions. When the pH value of the solution is reduced from 7.4 to 5.0, DOX-loaded micelles can be rapidly triggered to release encapsulated DOX, suggesting these polymeric micelles represent promising candidate pH-responsive nanocarriers for controlled-release drug delivery and pharmaceutical applications.
Supramolecular Assembly Mediates the Formation of Single-Chain Polymeric Nanoparticles
(2015-10-01)
Cheng, Chih-Chia
;
Chang, Feng-Chih
;
Yen, Hsiu-Che
;
Lee, Duu-Jong
;
Chiu, Chih-Wei
A breakthrough innovation in water-based polymeric nanoparticles has enabled significant progress in mimicking the folding of natural proteins by generating novel "single-chain polymeric nanoparticles" (SCPNs) via supramolecular interactions. In this study, a practical approach to the living polymerization of functionalized oligo(ethylene glycol) methacrylate monomers allows the incorporation of self-constituted multiple hydrogen-bonded groups into physically cross-linked polymer networks, which enables the formation of highly functionalized SCPNs in an aqueous environment. The newly developed materials are particularly attractive from a practical point of view since they have a very low critical micellization concentration and uniform particle diameters of ca. 25 nm, making them extremely stable under dilute conditions. Concentration-dependent experiments showed that SCPNs formed at polymer concentrations up to 40 mg/mL with no significant change in morphology observed. Moreover, the formed SCPNs had a very high stability in an aqueous solution containing surfactant, suggesting potential for a wide variety of applications as a promising candidate nanocarrier for bioimaging, controlled release, and drug delivery systems.