Morphology Control and Applications of Block Copolymers in Anodic Aluminum Oxide Templates

• Main Authors: Chu, Chiang-Jui, 朱強瑞
• Other Authors: Chen, Jiun-Tai
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/cjh5a8

碩士 === 國立交通大學 === 應用化學系碩博士班 === 102 === Block copolymers have been extensively studied over the last few decades because they can self-assemble into well-ordered nanoscale structures. The morphologies of block copolymers in confined geometries, however, are still not fully understood. In this study, we investigate the fabrication and morphology characterization of polystyrene-block-polydimethylsiloxane（PS-b-PDMS） block copolymers confined in the nanopores of anodic aluminum oxide（AAO） templates. We observe that the block copolymers can wet the nanopores using a novel solvent-annealing-induced nanowetting in templates method（SAINT）. The unique advantage of this method is that the problem of thermal degradation can be avoided. In addition, the morphologies of PS-b-PDMS nanostructures can be controlled by changing the wetting conditions. In this thesis, we first introduce the concept of block copolymers, the confinement effect, and the fabrication of AAO templates（Chapter 1）. Then the experimental materials and characterization instrument are presented（Chapter 2）. The experimental results are divided into four parts, in which different experimental parameters are controlled. In the first part（Chapter 3）, the effects of three different solvent vapors（toluene, hexane, and a co-solvent of toluene and hexane）on the morphologies of PS-b-PDMS are discussed. Porous PS nanostructures can also be prepared by etching the PDMS domains selectively with HF. Following the first part, we investigate more detail about the co-solvent ratio on the morphology of PS-b-PDMS in the second part（Chapter 4）. We find that the morphologies can be finely tuned by changing the co-solvent ratio. Surprisingly, the solvent-vapor-controlled morphologies can be reversibly switched by annealing the PS-b-PDMS nanostructures in different solvent vapors. The reversible experiments can be repeated up to four times. In the third part（Chapter 5）, we study the effect of the nanopore size by using AAO templates with pore sizes at ~200 nm, ~60 nm, and ~30 nm. The pore size is found to play a more important role than the type solvent does. In the fourth part（Chapter 6）, we develop a three-dimensional mask（3-D mask） strategy using the PS-b-PDMS nanostructures as the etching mask. The HF solution can etch the PDMS domains selectively. Therefore, the surface of the uncovered AAO walls can be further etched, resulting in the formation of nanopattern on the curved AAO walls. The etched AAO membranes can again be used as templates for making PMMA nanostructures. In the last chapter（Chapter 7）, we summarize the all the experimental results and propose some future works. Block copolymers have been extensively studied over the last few decades because they can self-assemble into well-ordered nanoscale structures. The morphologies of block copolymers in confined geometries, however, are still not fully understood. In this study, we investigate the fabrication and morphology characterization of polystyrene-block-polydimethylsiloxane（PS-b-PDMS） block copolymers confined in the nanopores of anodic aluminum oxide（AAO） templates. We observe that the block copolymers can wet the nanopores using a novel solvent-annealing-induced nanowetting in templates method（SAINT）. The unique advantage of this method is that the problem of thermal degradation can be avoided. In addition, the morphologies of PS-b-PDMS nanostructures can be controlled by changing the wetting conditions. In this thesis, we first introduce the concept of block copolymers, the confinement effect, and the fabrication of AAO templates（Chapter 1）. Then the experimental materials and characterization instrument are presented（Chapter 2）. The experimental results are divided into four parts, in which different experimental parameters are controlled. In the first part（Chapter 3）, the effects of three different solvent vapors（toluene, hexane, and a co-solvent of toluene and hexane）on the morphologies of PS-b-PDMS are discussed. Porous PS nanostructures can also be prepared by etching the PDMS domains selectively with HF. Following the first part, we investigate more detail about the co-solvent ratio on the morphology of PS-b-PDMS in the second part（Chapter 4）. We find that the morphologies can be finely tuned by changing the co-solvent ratio. Surprisingly, the solvent-vapor-controlled morphologies can be reversibly switched by annealing the PS-b-PDMS nanostructures in different solvent vapors. The reversible experiments can be repeated up to four times. In the third part（Chapter 5）, we study the effect of the nanopore size by using AAO templates with pore sizes at ~200 nm, ~60 nm, and ~30 nm. The pore size is found to play a more important role than the type solvent does. In the fourth part（Chapter 6）, we develop a three-dimensional mask（3-D mask） strategy using the PS-b-PDMS nanostructures as the etching mask. The HF solution can etch the PDMS domains selectively. Therefore, the surface of the uncovered AAO walls can be further etched, resulting in the formation of nanopattern on the curved AAO walls. The etched AAO membranes can again be used as templates for making PMMA nanostructures. In the last chapter（Chapter 7）, we summarize the all the experimental results and propose some future works.