Sulfonated Poly(Arylene Ether Sulfone) Copolymers - Acid and Salt Form: Potential Biofunctional Polymers

Abstract

The synthesis, characterization and preliminary evaluation of the potential for biofunctionality of strong, ductile sulfonated poly(arylene ether sulfone) copolymers of controlled hydrophilicity are described herein. A series of film forming random (statistical) copolymers were made from 4,4'-biphenol and a stoichiometric mixture of 3,3'-disulfonated and non-sulfonated 4,4'-dichlorodiphenyl sulfone; the degree of disulfonation varied from 10-60%. The copolymers were characterized by intrinsic viscosity, DSC, TGA and molecular weight (GPC). Preliminary evaluation of the potential of these copolymers in the acid or basic salt form for biocompatibility and biomedical applications was conducted via water uptake and contact angle measurements. The copolymers were cast into films from 10wt. percentage solutions in DMAc. Films were converted from the salt form to the acid form through treatment with concentrated H2SO4, and from acid form to sodium salt form by treatment with base. The surface of the films were characterized by XPS that confirmed full conversion to the intended form. The water uptake measurements showed that the acid form absorbed a maximum of ~ 800wt. percentage, and the salt forms absorbed a maximum of ~70 to 100wt. percentage. The contact angle between a water droplet and the surface of the copolymer films in the potassium salt form was measured using the Sessile Drop method, and it decreased as a function of the degree of sulfonation, in the range of 80-40o. The possibility of applications in pH-sensitive drug delivery systems is suggested.