🏛️國立陽明交通大學機構典藏

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Interplay of Template Constraints and Microphase Separation in Polymeric Nano-Objects Replicated from Novel Modulated and Interconnected Nanoporous Anodic Alumina
(2018-01-01)
Bayat, Haider
;
Lin, Chia-Hua
;
Cheng, Ming-Hsiang
;
Steuber, Marc
;
Chen, Jiun-Tai
We report on a versatile strategy to fabricate shape-controlled polymeric nano-objects with an internal compartmentalized structure by replication from pore-diameter-modulated and interconnected nanoporous anodized aluminum oxide (AAO). The AAO with modulated pore diameters is synthesized in a refined temperature-modulated hard anodization (TMHA) approach, by alternating the flow rate of an air stream cooling the electrolyte. Through pore-widening of the templates with modulated pore diameters, a stable interconnected 3D network with transversal ellipsoidal holes is fabricated as a second template structure. From these unprecedented template structures exhibiting modulated pores and an intricate 3D network structure, shape-controlled polymeric nano-objects are replicated using the melt wetting method with polystyrene homopolymer (PS) and cylinder-forming block copolymer polystyrene-block-polydimethylsiloxane (PS298-b-PDMS195). The replicated nanostructures are separated into individual anisotropically shaped nanocapsules by passing the replicas through a polycarbonate membrane followed by gentle sonication. Inside the nano-objects, the microphase separation of PS298-b-PDMS195 affords parallel aligned nanophases, in which domain sizes and morphologies are different compared to the unconfined bulk according to transmission electron microscopy analyses. These advanced AAO platforms and the nanoscale polymer replicas offer new routes for compartmentalized nano objects with potential future relevance for applications ranging from drug nanocarriers to biosensors.
Rayleigh-Instability-Induced Transformation for Confined Polystyrene Nanotubes Prepared Using the Solvent-Vapor-Induced Wetting Method
(1970-01-01)
Fang, Zhi-Xuan
;
Chu, Chien-Wei
;
Tsai, Chia-Chan
;
Chang, Chun-Wei
;
Cheng, Ming-Hsiang
Polystyrene (PS) nanotubes prepared using the solvent-vapor-induced wetting method with anodic aluminum oxide templates are for the first time applied to study the thermal stabilities of polymer nanotubes confined in cylindrical geometries. The morphologies of the PS nanotubes and the corresponding transformed PS nanostructures driven by the Rayleigh instabilities after thermal annealing treatments are characterized by scanning electron microscopy. Morphology diagrams of the Rayleigh-instability-induced nanostructures for PS nanotubes prepared via the solvent-vapor-induced wetting method and the solution wetting method are constructed to study the differences in kinetics for samples using different wetting methods. Slower transformation kinetics for the PS samples prepared by the solvent-vapor-induced wetting method than those prepared by the solution wetting method are observed, indicating the better thermal stabilities and the relatively denser packings of the polymer chains in the nanopores for the PS samples prepared using the solvent-vapor-induced wetting method.
Shaping the Light: The Key Factors Affecting the Photophysical Properties of Fluorescent Polymer Nanostructures
(2016-12)
Chi, Mu-Huan
;
Su, Chun-Hsien
;
Cheng, Ming-Hsiang
;
Chung, Pei-Yun
;
Peng, Chi-How
To manipulate the functions of nanomaterials more precisely for diverse applications, the controllability and critical influencing factors of their properties must be thoroughly investigated. In this work, the macroscopic and microscopic effects are studied on the photophysical properties of various pyrene-ended poly(styrene-block-methyl methacrylate) nanostructures. Fluorescent polymer nanospheres, nanorods, and nanotubes are prepared by different template-based methods using anodic aluminum oxide membranes. Chain arrangements and conformations are determined as the key factors affecting the photophysical properties of the fluorescent polymer nanostructures. This work not only gives a deeper understanding of the effects on the photophysical properties of polymer nanomaterials influenced by morphologies, chain arrangements, and chain conformations, but also provides a reference for designing proper fluorescent nanostructures for specific applications.
Confinement Effects on the Optical Properties and Chain Conformations of Poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) Nanotubes
(2016-09)
Chu, Chien-Wei
;
Jeng, Kai-Sheng
;
Chi, Mu-Huan
;
Tsai, Chia-Chan
;
Cheng, Ming-Hsiang
Although many fabrication methods of conjugated polymer nanostructures have been developed, the effects of confinement on the morphologies, chain conformations, and optical properties of conjugated polymers are still not well understood. In this work, poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) (F8BT), a light-emitting conjugated polymer, is used to fabricate nanotubes by a solution wetting method using anodic aluminum oxide templates. The property changes under the nanoscale confinement have been investigated. The morphologies of F8BT nanostructures are characterized by scanning electron microscope, transmission electron microscope, and laser scanning confocal microscope. The data show the hollow morphologies and no or low crystallinity of the nanostructures. The optical properties are also measured using UV-vis absorption, photoluminescence, and confocal Raman spectroscopy. The spectroscopy data indicate that F8BT polymer chains have less intermolecular interactions and coplanarity under the confinement effect.

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🏛️國立陽明交通大學機構典藏

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