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Comparative Aminolysis Kinetics of Different Active Ester Polymer Brush Platforms in Postpolymerization Modification with Primary and Aromatic Amines

Arnold, Rachelle M., Sheppard, Gareth R., Locklin, Jason
Macromolecules 2012 v.45 no.13 pp. 5444-5450
adenosine monophosphate, aminolysis, aromatic amines, models, polymers
The kinetics of aminolysis between two different active ester polymer brush platforms, poly(4-pentafluorophenyl acrylate) (poly(PFPA)) and poly(N-hydroxysuccinimide-4-vinyl benzoate) (poly(NHS4VB)), are compared using primary and aromatic amines with varying reactivity toward postpolymerization modification. UV–vis was used to monitor the aminolysis of both brush platforms with 1-aminomethylpyrene (AMP), 1-aminopyrene (AP), and Ru(bpy)₂(phen-5-NH₂)(PF₆) (Ru²⁺A). Using a pseudo-first-order kinetics model, the pseudo-first-order rate constant (k′) was calculated for each system. The k′ of poly(PFPA) modified with AMP, AP, and Ru²⁺A were 2.46 × 10–¹, 5.11 × 10–³, and 2.59 × 10–³ s–¹, respectively, while poly(NHS4VB) can only be functionalized with the alkyl amine, albeit at a slower rate constant, k′ of 3.49 × 10–³ s–¹, compared to that of poly(PFPA) with AMP. The kinetics of surface-initiated photopolymerization of PFPA from oxide surfaces was also investigated as an effective method to control grafting density and film thickness.