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In this study, we have prepared pH/temperature-sensitive imprinted ionic poly(N-tert-butylacrylamide-co-acrylamide/maleic acid) [P(TBA-co-AAm/MA)] hydrogels for bovine serum albumin (BSA) by using molecular imprinting method. BSA adsorption from aqueous BSA solutions was investigated with two types of hydrogel systems prepared by non-imprinted and imprinted methods. Hydrogels imprinted with BSA showed higher adsorption capacity and specificity for BSA than hydrogels prepared by the usual procedure. At all studied conditions, the highest BSA adsorption was observed in the hydrogel imprinted with 8.63 wt.-% BSA. In addition, the imprinted hydrogels exhibited both for good selectivity BSA and high adsorption rate depending on the number of BSA-sized cavities. Adsorption studies showed that other stimuli, such as pH, temperature and initial BSA concentration also influenced the BSA adsorption capacity of both non-imprinted and imprinted hydrogels.

Poly(acrylamide-co-acrylic acid) [P(AAm-coAAc)] hydrogels were synthesized by the free-radical crosslinking copolymerization of acrylamide (AAm) monomer at fixed amount, but at changing amount of acrylic acid (AAc) as the ionic comonomer in water. The swelling behavior of the hydrogels thus obtained was analyzed in buffer solutions at various pHs. The polymer-solvent interaction parameter (v) and the average molecular mass between crosslinks (M c ) of the hydrogels were calculated from swelling studies in buffer solutions at various pHs and were related to the AAc content. The results indicated that the swelling behavior of the hydrogels at different pHs agreed with the modified Flory-Rehner equation based on the affine network model and the ideal Donnan theory. In addition, from differential curves of dO v /dpH versus pH, the volume phase transition pH (VPT-pH) was found to be 4.33 6 0.05, independent of the AAc content in the hydrogel. Scanning electron microscope (SEM) was used to identify the morphological changes in the hydrogel as the concentration of AAc increased. In water at 228C, an increase of the AAc content further increased the response rate of the hydrogels because of simultaneous increase of both the porosity and hydrophilicity of the network. In buffer solution with a pH increase from 9.0 to 2.0 at 228C, the hydrogels with more AAc also exhibited a more rapid deswelling rate than that of the hydrogels with less AAc.

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The single-electron transfer living radical polymerization (SET-LRP) of N-isopropylacrylamide (NIPAM) from silicon wafer modified with an initiator layer composed of 2bromopropionyl bromide (2-BPB) fragments is described. The amount of Cu(0) generated in situ by the disproportination of Cu(I) to Cu(0) and Cu(II) in the presence of 2,2 0 -bipyridine (2,2 0bpy) ligand and N,N-dimethylformamide (DMF) solvent at 90 C is dependent on the ratio of [CuBr]/[CuBr 2 ]. By proper selection of the [CuBr]/[CuBr 2 ] ratio, well-controlled SET-LRP polymerization of NIPAM was observed such that the thickness of the layer consisting of chains grown from the surface increased linearly with the molecular weight of chains polymerized in solution in identical. In addition, the calculation of grafting parameters, including surface coverage, r (mg/m 2 ); grafting density, R (chain/nm 2 ); and average distance between grafting sites, D (nm), from the number-average molecular weight, M n (g/mol), and ellipsometric thickness, h (nm), values indicated the synthesis of densely grafted poly(NIPAM) films and allowed us to predict a ''brush-like'' conformation. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5842-5847, 2010