Synthesis and Application of Poly(urea/malonamide) Dendrons

• Main Authors: Chia-Cheng Chang, 張家振
• Other Authors: 鄭如忠
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/46863660611514218130

博士 === 國立中興大學 === 化學工程學系所 === 99 === In this study, the dual-functional building block 4-isocyanato-4''(3, 3-dimethyl-2, 4-dioxo-azetidino) diphenylmethane (IDD) was used to prepare dendrons via a convergent route. Utilizing high reactivity of isocyanate and selective reactivity of azetidine-2, 4-dione of IDD, the poly(urea/malonamide) dendrons were synthesized via sequential addition reactions of IDD and diethyltriamine (DETA). The dendrons accompanied with peripheral long alkyl chains and urea/malonamide linkages enhance the Van de Waals force at peripheral part and the hydrogen bonding interaction at the focal part, respectively. Herein, based on this advantageous and unique characteristic, a series of self-assembly researches was attempted. First, we focused on the self-assemibly behavior of dendrons. Generation one dendron with peripheral stearyl groups ([G1]-C18) was capable of forming a gel in THF. The morphology of various concentrations of dendrons was characterized by XRD and SEM. In addition, the Jeffamine ED-2003 was utilized as the core to prepare amphiphilic dumbbell shaped dendrimers. The morphology of various concentrations of dumbbell shaped dendrimers was investigated by AFM, SEM and TEM. The results showed that better micelle stability was achieved by the incorporation of the higher generations of dendrons. This is because of the presence of stronger intermolecular or intramolecular interactions. Moreover, ordered micelle morphologies were obtained in the water and organic solvents, respectively. Apart from that, the dendrons were grafted onto polymers to prepare the dendritic side-chain polymers. The dendrons with strong intermolecular hydrogen bonding interactions and Van de Waals forces are expected to facilitate self-assembly of the dendritic side-chain polymers. Consequently, by means of breath-figure and double emulsion process, honeycomb polymer films and polymer vesicles can be easily obtained, respectively. Herein, various factors, including the concentration, the generation of the dendritic side-chain polymers, relative humidity (RH), and the grafting ratio, were taken into account to prepare ordered honeycomb-like polymeric films. In addition, a suitable hydrophobic/hydrophilic segment ratio in the polymer is also an important factor. On the other hand, for the preparation of polymer vesicles, the self-assembly behavor of the dendritic side-chain polymers was investigated by using different pH values and content of ethanol during the double emulsion process. Indeed, vesicles could be obtained from dendrons using double emulsion process. Moreover, vesicles or multi-vesicles could also be obtained from the dendritic side chain polymers via double emulsion process. The presence of the dendrons in the polymer would enhance its self-assembly behavior and the stability of vesicles. Finally, a facile and versatile assembly process for highly entangled carbon nanotube scaffolds was presented. Multi-walled carbon nanotubes (MWNTs) modified with dendrons demonstrated improved dispersion. In addition, macroporous MWNT films were directly prepared by a breath figure process. The macroporous MWNT films are potentially useful for further applications such as optoelectronic devices, electrochemical devices, or energy storage.