利用掌性嵌段共聚物模化製備奈米混成與多孔材料

Nanohybrid and Nanoporous Materials from Chiral Block Copolymer Templating

薛涵宇(Han-Yu Hsueh)

指導教授 ： 何榮銘

國立清華大學/工學院/化學工程學系/博士(2011年)

https://doi.org/10.6843/NTHU.2011.00211

摘要

Block copolymers (BCPs) that consist of chemically different components can self-assemble into various ordered nanostructures due to the incompatibility of constituted blocks. Recently, BCPs composing of chiral entities, designated as chiral block copolymers (BCP*s), have been designed to fabricate helical architectures. Helical phases were found in the self-assembly of polylactide-containing BCPs*. In this study, we aim to take advantage of the degradable character of ester groups in polylactide-containing BCPs* so as to create nanoporous polymer from self-assembled nanostructures by hydrolysis of polylactides and used it as template for following templated syntheses, such as sol-gel reaction and electroless plating. Consequently, a variety of well-defined nanostructures of polymer/ceramic and polymer/metal nanohybrids can be created.
Herein, we demonstrate that, by using gyroid-forming nanoporous polymer matrix as a template for sol-gel process, inorganic nanoporous SiO2 materials with high porosity and well-defined periodic nanostructures can be successfully fabricated after the degeneration of polymer matrix. Owing to the high porosity (over 60%) and the low refractive index of SiO2, a single-component material with an extremely low refractive index (as low as 1.10) can be obtained so as to provide an excellent materials as antireflection structure. Also, Titanium alkoxide was used as a model system to demonstrate the achievement of templated sol-gel process from reactive transition metal alkoxides. Through the control of hydrolysis and condensation reaction for the sol-gel process, the morphological evolution of polymer/ceramic nanohybrids from templating can be well developed. Consequently, polymer/ceramic nanohybrids with various shapes and components can be precisely synthesized via templated sol-gel reaction. Similar tempalted synthetic scheme can also be exploited to obtain polymer/metal nanohybrids via modified electroless plating in BCP* templates. Well-ordered polymer/Ni nanohybrids with Ni gyroid nanostructures can be prepared so as to form nanoporous Ni materials after removal of polymer template. This easy process for the fabrication of metallic nanoporous materials with well-ordered nanostructures is appealing in many fields of applications.
Nanoporous gyroid SiO2 can also be used as an inorganic template for templated synthesis. Note that SiO2 can be simply degenerated by using base aqueous solution. As a result, it is possible to give a conceptual approach for the creation of any combination of two-component gyroid nanostructured materials. By using nanoporous gyroid SiO2 as template, templated synthesis for polymers, ceramics and metals can be carried out and followed by removal of SiO2 so as to create the second-generation template; it is referred to the concept of replacement templates. Namely, an easy approach to create nanohybrids with different material properties can be established; the novel two-component gyroid nanostructured materials are referred to Matrix-Network switchable nanohybirds with precise control of hybridized nanostructures and switchable components for hybridization.

關鍵字

溶液-凝膠法 ； 無電電鍍法 ； 模板 ； 高分子嵌段共聚物 ； 奈米混成材料 ； 奈米多孔材料

並列摘要

無資料

並列關鍵字

Sol-gel reaction ； Electroless plating ； Block copolymers ； Templates ； Nanohybrid materials ； Nanoporous materials

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