Self-Assembly Behavior of Block Copolymers Induced by Nanocylinders

• Main Authors: Lin-En Chi, 紀霖恩
• Other Authors: 諶玉真
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/15393185028585524920

碩士 === 國立臺灣大學 === 高分子科學與工程學研究所 === 104 === Amphiphilic diblock copolymers can self-assemble in a selective solvent to form various structures. Diverse morphologies of self-assembly can also be observed in the polymer melt of diblock copolymers. The helical structure has great potential for many applications. Nonetheless, the helical structure of diblock copolymers in polymer solutions has seldom been reported and the formation of helixes of diblock copolymers in a selective solvent is still a challenge. However, helical wrapping of a nano-cylinder provides a possibility for the formation of helix of diblock copolymers. In this study, DPD simulations are performed to explore the self-assembled morphology of diblock and triblock copolymers onto a nano-cylinder. It is found that the presence of the nano-cylinder is able to induce helical wrapping of diblock copolymers. Helical ellipsoids and helical toroid appear. Moreover, the morphology of the helical aggregate changes with the polymer concentration. With increasing the number of polymers N, helical ellipsoids transform into helical cylinder as the polymer concentration exceeds a critical value. The influences of polymer concentration, block compositions, and the interaction between polymer and nano-cylinder on the morphology are investigated. As a result, a morphological phase diagram is constructed. It is also found that the presence of the nano-cylinder has the ability to induce helical wrapping of triblock copolymers. With fixed number of polymers and interaction strengths between polymer and nano-cylinder, two different morphological phase diagrams are presented for triblock copolymers with different compositions. Additionally, it is also discovered that the concentration effect on morphology for triblock copolymers is different from that for diblock copolymers. It may transform into other conformation with different number of polymers N. Our simulation results may shed some light on the experimental development for the formation of the helical suprastructure of diblock and triblock copolymers in solutions.