The surface polyion complex gel (sPIC gel), which possesses chemically bonded nonionic gel moiety, was designed using N-vinylacetamide (NVA), N-vinylforamide (NVF), and vinyl phosphonic acid (VPA). Taking advantage of the property of NVF as vinylamine (VAm) precursor, the cationic moiety was introduced only onto the surface of poly(NVA-co-NVF), producing surface hydrolyzed poly(NVA-co-NVF-co-VAm), and the successive polymerization of VPA inside the gel successfully produced sPIC gel. The swelling ratio of the sPIC gel was investigated under various pH conditions, and compared with that of the fully polyion complex gel (PIC gel), using totally hydrolyzed poly(NVA-co-VAm). The swelling ratio of sPIC gel ranged between 14 and 25, while that of the PIC gel ranged between 2 and 5. The anionic compound, AR, showed a sustained release from sPIC gel at pH 2, due to the electrostatic interactions. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 562-566