AMPHIPHILIC BLOCK COPOLYMERS OF VINYL ETHERS BY LIVING CATIONIC POLYMERIZATION .3. ANIONIC MACROMOLECULAR AMPHIPHILES WITH PENDANT CARBOXYLATE ANIONS

Anionic amphiphilic block polymers of vinyl ethers (VEs) -[CH2CH(OCH2CH2R’)]m- [CH2CH(OR)]n- (R’ = CH(COO-Na+)2, CH2COC-Na+, CH2COOH; R = n-C16H33, i-C8H17 n-C4H9; m 20, n = 1-17) were prepared, in which the hydrophilic segment has pendant carboxylate anions or carboxylic acid groups and the hydrophobic segment has alkyl chains. Their precursors, -[CH2CH(OCH2CH2R”)]m- [CH2CH(OR)]n- (R” = CH(COOEt)2), were obtained from a malonic ester containing VE (CH2= CHOCH2CH2CH(COOEt)2) and an alkyl VE by sequential living cationic polymerization initiated by a mixture of hydrogen iodide and iodine. Hydrolysis and decarboxylation of the malonic ester pendants of the precursors led to the target amphiphiles. These block polymers had excellent surface activity and lowered the surface tension of their aqueous solutions. For example, the highest surface activity was attained (minimum 25.8 dyn/cm; 1.0 wt %, 25 °C) when the number of total carbon atoms in the alkyl VE chain was 20-40 and m ≅ 20 but independent of the kind of the hydrophilic group. The extent of the surface tension decrease was greatly affected by the structures and the combinations of the hydrophilic and the hydrophobic groups. The surface activity of these anionic amphiphiles was also compared with that of nonionic and cationic amphiphilic block polymers of VEs. © 1990, American Chemical Society. All rights reserved.