title: Enhanced Surface Interaction of Water Confined in Hierarchical Porous Polymers Induced by Hydrogen Bonding.
abstract: Hierarchical porous polymer systems are increasingly applied to catalysis, bioengineering, or separation technology because of the versatility provided by the connection of mesopores with percolating macroporous structures. Nuclear magnetic resonance (NMR) is a suitable technique for the study of such systems as it can detect signals stemming from the confined liquid and translate this information into pore size, molecular mobility, and liquid-surface interactions. We focus on the properties of water confined in macroporous polymers of ethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate [poly(EGDMA-co-HEMA)] with different amounts of cross-linkers, in which a substantial variation of hydroxyl groups is achieved. As soft polymer scaffolds may swell upon saturation with determined liquids, the use of NMR is particularly important as it measures the system in its operational state. This study combines different NMR techniques to obtain information on surface interactions of water with hydrophilic polymer chains. A transition from a surface-induced relaxation in which relaxivity depends on the pore size to a regime where the organic pore surface strongly restricts water diffusion is observed. Surface affinities are defined through the molecular residence times near the network surface.
authors.affiliation: FaMAF-Universidad Nacional de Córdoba and IFEG-CONICET , 5016 Córdoba, Argentina.
authors.forename: Emilia V
authors.initials: EV
authors.lastname: Silletta
authors.affiliation: FaMAF-Universidad Nacional de Córdoba and IFEG-CONICET , 5016 Córdoba, Argentina.
authors.forename: Manuel I
authors.initials: MI
authors.lastname: Velasco
authors.affiliation: Departamento de Química Orgánica, Facultad de Ciencias Químicas (IMBIV-CONICET), Universidad Nacional de Córdoba , Haya de la Torre y Medina Allende, Edificio de Ciencias II-Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Cesar G
authors.initials: CG
authors.lastname: Gomez
authors.affiliation: Departamento de Química Orgánica, Facultad de Ciencias Químicas (IMBIV-CONICET), Universidad Nacional de Córdoba , Haya de la Torre y Medina Allende, Edificio de Ciencias II-Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Miriam C
authors.initials: MC
authors.lastname: Strumia
authors.affiliation: Fachgebiet Technische Physik II/Polymer Physik, Institute of Physics, Technische Universität Ilmenau , P.O. Box 100 565, 98684 Ilmenau, Germany.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Stapf
authors.affiliation: Fachgebiet Technische Physik II/Polymer Physik, Institute of Physics, Technische Universität Ilmenau , P.O. Box 100 565, 98684 Ilmenau, Germany.
authors.forename: Carlos
authors.initials: C
authors.lastname: Mattea
authors.affiliation: FaMAF-Universidad Nacional de Córdoba and IFEG-CONICET , 5016 Córdoba, Argentina.
authors.forename: Gustavo A
authors.initials: GA
authors.lastname: Monti
authors.affiliation: FaMAF-Universidad Nacional de Córdoba and IFEG-CONICET , 5016 Córdoba, Argentina.
authors.forename: Rodolfo H
authors.initials: RH
authors.lastname: Acosta