Macromolecules, Vol.41, No.2, 305-311, 2008
Copolymerization of amino acid functionalized norbornene monomers. Synthesis of Amphiphilic block copolymers forming reverse micelles
Amino acid derived novel norbornene monomers, N,N'-(exo-bicyclo[2.2.1]hept-5-en-2,3-diyldi-carbonyl) biS-L-leucine methyl ester (1) and N,N'-(exo-bicyclo[2.2.1]hept-5-en-2,3-diyldicarbonyl) biS-L-leucine (2) were synthesized and polymerized with Grubbs second generation ruthenium catalyst. The homopolymers, random, and block copolymers with number-average molecular weights ranging from 16 000 to 30 000 were obtained in good yields. The block copolymers with 1:2 unit ratios of 75:25, 62:38, and 50:50 were soluble in acetone, while the random copolymers with the same ratios were partly insoluble in the solvent. H-1 NMR, contact angle, dynamic light scattering, and atomic force microscopy measurements revealed that the block copolymer form micelles with a diameter around 100 nm in acetone consisting of a hydrophilic core of poly(2) and a hydrophobic shell of poly(1).