| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2006: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2005: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Research Abstract |
ReI[1S,5R,6S]-3-Oxabicyclo[3.2.1] octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione) (DAn), a dianhydride having a unique regioselectivity upon reaction with aromatic amines, was sequentially treated with each 0.5 equiv. of hydrophilic and hydrophobic diamines to give a variety of amphiphilic alternating copolyimides. Dynamic light scattering analysis of their aqueous solutions revealed that 1) the size of aggregate of alternating copolyimides is considerably larger than that of random copolyimides, and 2) the size depends on the alkyl chain length in the side chain. Vesicle formation was confirmed by means of TEM observation.
However, the degree of imidization was around 70-80%. This low value was considered to be problematic for the precise evaluation of aggregating behavior. Then, the conditions for the imidization reaction was examined in detail, and it was found that chemical imidization gave better results. The molecular weight of the copolyimides were around several thousands, but later we found that it can be increased up to >20000. It is highly needed that a set of polyimides having different degree of imidization and different molecular weights should be systematically investigated.
Meanwhile, on the way of this research, we happened to find that the copoly(amide acid)s, a synthetic precursor for the copolyimides, also shows aggregating behavior in a certain conditions. A relationship was found between the molecular structure and the size of the aggregates. This research was extended to the development of photoresponsive macromolecular aggregates.
It is highly expected that the result of the present research will lead to the development of novel amphiphilic copolyimide/copoly(amide acid)-based materials.
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