FUNDAMENTAL CHEMICAL DIFFERENCES BETWEEN POLYACIDIC AND POLYBASIC MATERIALS FOR THE DESIGN OF pH-RESPONSIVE CONTROLLED RELEASE SYSTEMS

摘要

The behavior of polyanionic, polycationic and ampholytic polymers varies substantially due not only to differences in ionization, but the response of polycationic materials to pH buffers and ionic strength make them much more difficult to design for reproducible pH-responsive controlled release. Experimental results show that ampholytic materials display dual pH-sensitivity, but have a sharper response to the pK_a of poly(methacrylic acid) than the pK_b due to poly(N,N-diethylaminoethyl methacrylate).