Microphase separation and Molecular Conformation Analysis of AB2 Miktoarm Star Copolymers by Dissipative Particle Dynamics
Date Issued
2006
Date
2006
Author(s)
Yu, Shih-Tung
DOI
zh-TW
Abstract
We employ the dissipative particle dynamics (DPD) to simulate the microphase separation behavior of AB2 miktoarm star copolymers. The phase diagram is constructed in terms of the interaction parameters and composition, is in a near quantitative agreement with that predicted by self-consistent mean-field (SCMF) theory. However, when the composition of B is small, we observe that AB2 can not easily form the ordered microstructures as have been predicted by SCMF. Instead, they form a tube-like phase, which frequently has been observed in experiments. In addition, though the systems with smaller value of A composition form the spheres as SCMF predicted, we find that due to the finite size effects, it becomes difficult to examine the most stable packing arrays of spheres. In the analysis of radius of gyration, when the interaction parameter increases so that AB2 copolymers transform from a disordered into an ordered state, we find that the radius of gyration for each A and B arm remains somewhat a constant. However, the overall radius of gyration of AB2 significantly increases with the interaction parameter. This manifests the fact that in order to reduce the contacts between A and B, the angle between A and B arms increases and the angle between B and B arms decreases. When the interaction parameter is fixed, the radius of gyration increases with fA. By analyzing the power law , we find that the B arms are more stretchable than A arms.
Subjects
星形塊狀共聚物
分散粒子動力學
miktoarm star copolymer
Dissipative Particle Dynamics
Type
thesis
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