Synthesis and Morphology of Dendritic Block Copolymers
Date Issued
2014
Date
2014
Author(s)
Su, Yu-An
Abstract
This work consists of the synthesis of dendritic block copolymers (DBCs) with various flexible chain lengths, architectures and numbers of branching generations, and the effects of these structural factors on the morphologies. A series of poly(urethane/malonamide)dendrons were synthesized first based on the reactive building block, 4-isocyanate-4-(3,3-dimethyl-2,4-dioxo-azetidine)-diphenylmethane (IDD) with different numbers of branching generations. All the dendrons were confirmed by FT-IR, 1H-NMR, EA and Mass. Subsequently, the flexible poly(oxyalkylene) reacted with the reactive dendrons with different numbers of branching generations. Hence, several series of DBCs were synthesized and confirmed by FT-IR, 1H-NMR and GPC. Because the high branching generations of dendrons were difficult to self-assemble, a soft segment was incorporated to enhance the x values of DBCs. As a result, the presence of microphase separation between the interface would certainly induce a pattern of the architecture of dendrons with high branching generations to self-assemble. In addition, two melting transitions, pertaining to the partial micro-separation were observed as measured by DSC. In the L1DBC system, Tm1 and Tm2 were increased from 20 oC, 60 oC to 37 oC, 86 oC, respectively, when a dendron of higher generation was incorporated onto a DBC. The TEM image of L1DBC showed the morphologies were lamellar, worm-like and sphere, dependent on increasing generation of dendrons in L1DBCs accordingly. Furthermore, the morpholgy of L2D0BC and D2D0BC were cylinder and lamellar by the extension of flexible chain lengths and architecture conformation, respectively. All the DBCs were confirmed by Small angle x-ray scattering (SAXS) and Igor software curve fitting.
Subjects
樹枝狀分子
樹枝狀共聚物
自組裝
Type
thesis
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