Conformational behaviour of copolymers of acrylic acid and methacrylic acid in aqueous solution

✍ Scribed by Jan Jager; Jan B.F.N. Engberts

• Publisher: Elsevier Science
• Year: 1987
• Tongue: English
• Weight: 400 KB
• Volume: 23
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(87)90151-0

✦ Synopsis

The conformational behaviour of four copolymers of acrylic acid (AA) and methacrylic acid (MAA) has been studied and compared with that of poly(acrylic acid) and poly(methacrylic acid). Potentiometric titrations, solubility measurements employing the water-insoluble dye Orange OT and spectroscopic studies using ethidium bromide all indicate that the unionized copolymers can only attain a tightly coiled, compact conformation when the MAA content exceeds about 50%. This conclusion is confirmed by kinetic studies of the neutral hydrolysis of 1-benzoyl-3-phenyl-l,2,4-triazole in aqueous solution (pH ca 4) in the presence of the copolymers. Considerable retardation is found when the hydrophobic substrate binds to hydrophobic microdomains and subsequently reacts in a relatively "dry" microenvironment. Isobaric activation parameters for the hydrolysis vary with the composition of the copolymer and support the above interpretation.