The polysilsesquioxanes (PSQ) having alkoxyethylamide groups were prepared from the silane coupling reagents, prepared by addition reaction of alkoxyethylamines to (3-isocyanatopropyl)triethoxysilane, by condensation under acidic conditions. In the obtained PSQs, those having bis(methoxyethyl)amide or bis(ethoxyethyl)amide group showed reversible thermoresponsive phase separation in an aqueous solution. The PSQs formed by the co-condensation of such silane coupling reagents, the feed mole ratio of which were changed, also showed the thermoresponsive aggregation at the temperatures reflected with the ratios of alkoxyethyl groups.
A polysilsesquioxane with a bis(2-methoxyethyl)amide group and 15-crown-5-ether ring (MCPSQ) was newly prepared by the co-condensation of silane coupling reagents, which were obtained from (3-isocyanatopropyl)triethoxysilane and the corresponding amines with the respective groups. MCPSQ showed the expected amphiphilic and thermoresponsive properties. The behaviors of hydrophobic aggregation of MCPSQ in the aqueous solutions containing the chlorides of lithium, potassium and sodium reflected the selective ion recognition property due to the presence of the crown ether. The highest aggregation temperature of 32 1C was observed in the solution containing sodium ion as expected from the coordination ability of the crown ether group. With the use of the sodium salt of 4-phenylazobenzoic acid as an additive in the aqueous solution of MCPSQ, the aggregation temperature was changed according to the photochemical isomerization of the phenylazobenzoate group. The results show the efficient coordination of the sodium salt with the crown ether ring.
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