| abstract |
It is an object of the invention to provide a polymersome excellent in the safety and feeling in use; in particular, there is no sticky feeling but there is a good refreshing feeling; and with excellent base-agent stability. A polymersome of the present invention comprises a block-type alkylene oxide derivative represented by the following formula (I) as the membrane component: n R 1 O-[(EO) I (AO) m (EO) n ]-R 2 (I)n n wherein AO is an oxyalkylene group having 3 to 4 carbon atoms, EO is an oxyethylene group, m and 1+n are the average addition mole numbers for the oxyalkylene group and the oxyethylene group, respectively, and 1≦m≦70, 1≦1+n≦70; the percentage of the oxyethylene groups with respect to the sum of the oxyalkylene groups having 3 to 4 carbon atoms and the oxyethylene groups is 20 to 80 mass %; the addition pattern of the oxyalkylene groups having 3 to 4 carbon atoms and the oxyethylene groups is block-type; and R 1 and R 2 are identical or different hydrocarbon groups having 1 to 4 carbon atoms. |