Interaction of Phenolic Pollutants with PNIPA hydrogels

Host–guest interactions in poly(N-isopropylacrylamide) gel

“…In aqueous phenol solutions a limited reduction in swelling occurs up to 52 mM, at which an abrupt change occurs already at 20 °C. Above this concentration the phenol loaded system exhibits only limited swelling [6][7]. Ibuprofen causes only a minor depletion that is proportional to its concentration in the swelling medium in the wide concentration range of the experiments, while dopamine shows no detectable influence at all up to 500 mM.…”

“…PNIPA exhibits a concentration dependent response in the presence of phenols. [6][7] Binding of phenol to PNIPA is mediated by hydrogen bonding between the amide group of the NIPA chain and the hydroxyl group of the phenol molecule [11]. The associative behaviour between phenol and PNIPA was also proved by small-angle neutron scattering (SANS) and solid state NMR techniques [5,8].…”

“…The influence of various incorporated small molecules on the swelling behaviour of the PNIPA hydrogels has been the focus of our research group for a decade [5][6][7][8][9][10]. Swelling and DSC investigations have shown that certain organic molecules present in the swelling medium may significantly reduce the temperature of the volume phase transition (VPT), and that the shift depends on their concentration.…”

“…Swelling and DSC investigations have shown that certain organic molecules present in the swelling medium may significantly reduce the temperature of the volume phase transition (VPT), and that the shift depends on their concentration. At a particular guest molecule concentration, deswelling as abrupt as that in water at 34°C may occur already at room temperature, in which the concentration is characteristic of the dissolved molecule (critical concentration) [5][6][7][8][9]. Some molecules have only a slight effect or no affect at all [10].…”