Effect of intercalant content of mica on the various properties for the charged nanocomposite poly(N-isopropyl acrylamide) hydrogels

Abstract

In this study, we intend to adjust the charge properties of the poly(N-isopropylacrylamide) [Poly(NIPAAm)] gel by using anionic clay and cationic monomer. Hence, two series of nanocomposite hydrogels bearing different charges were designed from NIPAAm, intercalated mica (IM) (NIM-series) and NIPAAm, IM, trimethyl (acrylamido propyl) ammonium iodide (TMAAI) (NTIM-series), respectively. The mica was first intercalated with different contents of intercalant, trimethyl (acrylamido propyl) ammonium chloride (TMAACl), based on the cationic exchange capacity (CEC) of mica. The effect of the CEC value of IM and IM content on the charge property, swelling behaviors, mechanical properties, and drug-release behaviors of the present gels were investigated. Results showed that the negative charges for NIM series gels decrease with increase in CEC values of the IM (from −11 to −6 mV), the positive charges for NTIM series gels also decrease with increase in CEC values of the IM (from +36 to +18 mV). The swelling behaviors and mechanical properties for the NTIM gels were significantly enhanced by IM content and CEC values of the IM. The microstructures, morphologies, and drug-release behaviors in these two series gels are also investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2277–2287, 2007