BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 Lecture 9: Polyelectrolyte Hydrogels Last Day: Physical hydrogels Structure and chemistry Toda polyelectrolyte hydrogels, complexes, and coacervates rolyte multilayer theory of swelling in ionic hydrogels Reading S.K. De et aL., 'Equilibrium swelling and kinetics of pH-responsive hydrogels: Models experiments, and simulations, J. Microelectromech. Sys. 11(5)544 (2002) Supplementary Reading L. Brannon-Peppas and N.A. Peppas, 'Equilibrium swelling behavior of pH-sensitive hydrogels, Chem Eng. Sci. 46(3)715-722(1991) USE DEMO OF AMINOETHYL METHACRYLATE HYDROGEL TO SHOW PH-DEPENDENT SWELLING? Covalent polyelectrolyte hydrogels Response of polyelectrolyte gels to pH of environment o Reminder of the response of ionizable groups to pH changes ionization of charged groups 14 o Presence of ionizable groups makes polyelectrolyte hydrogels sensitive to p o lonic strength o Electric fields o D Lecture 9-polyelectrolyte hydrogels 1of17BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Lecture 9: Polyelectrolyte Hydrogels Last Day: Physical hydrogels Structure and chemistry Today: polyelectrolyte hydrogels, complexes, and coacervates Polyelectrolyte multilayers theory of swelling in ionic hydrogels Reading: S.K. De et al., ‘Equilibrium swelling and kinetics of pH-responsive hydrogels: Models, experiments, and simulations,’ J. Microelectromech. Sys. 11(5) 544 (2002). Supplementary Reading: L. Brannon-Peppas and N.A. Peppas, ‘Equilibrium swelling behavior of pH-sensitive hydrogels,’ Chem. Eng. Sci. 46(3) 715-722 (1991). USE DEMO OF AMINOETHYL METHACRYLATE HYDROGEL TO SHOW PH-DEPENDENT SWELLING? Covalent polyelectrolyte hydrogels Response of polyelectrolyte gels to pH of environment o Reminder of the response of ionizable groups to pH changes: ionization of charged groups 1.2 1 0.8 0.6 0.4 0.2 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH o Presence of ionizable groups makes polyelectrolyte hydrogels sensitive to: o pH o Ionic strength o Electric fields o (T) Lecture 9 – polyelectrolyte hydrogels 1 of 17