title: Spatially Resolved Monitoring of Drying of Hierarchical Porous Organic Networks.
abstract: Evaporation kinetics of water confined in hierarchal polymeric porous media is studied by low field nuclear magnetic resonance (NMR). Systems synthesized with various degrees of cross-linker density render networks with similar pore sizes but different response when soaked with water. Polymeric networks with low percentage of cross-linker can undergo swelling, which affects the porosity as well as the drying kinetics. The drying process is monitored macroscopically by single-sided NMR, with spatial resolution of 100 μm, while microscopic information is obtained by measurements of spin-spin relaxation times (T2). Transition from a funicular to a pendular regime, where hydraulic connectivity is lost and the capillary flow cannot compensate for the surface evaporation, can be observed from inspection of the water content in different sample layers. Relaxation measurements indicate that even when the larger pore structures are depleted of water, capillary flow occurs through smaller voids.
authors: FaMAF-Universidad Nacional de Córdoba and IFEG-CONICET, 5000 Córdoba, Argentina.
authors: Manuel Isaac
authors: MI
authors: Velasco
authors: FaMAF-Universidad Nacional de Córdoba and IFEG-CONICET, 5000 Córdoba, Argentina.
authors: Emilia V
authors: EV
authors: Silletta
authors: 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: Cesar G
authors: CG
authors: Gomez
authors: 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: Miriam C
authors: MC
authors: Strumia
authors: Department of Technical Physics II/Polymer Physics, Ilmenau University of Technology , 98684 Ilmenau, Germany.
authors: Siegfried
authors: S
authors: Stapf
authors: FaMAF-Universidad Nacional de Córdoba and IFEG-CONICET, 5000 Córdoba, Argentina.
authors: Gustavo Alberto
authors: GA
authors: Monti
authors: Department of Technical Physics II/Polymer Physics, Ilmenau University of Technology , 98684 Ilmenau, Germany.
authors: Carlos
authors: C
authors: Mattea
authors: FaMAF-Universidad Nacional de Córdoba and IFEG-CONICET, 5000 Córdoba, Argentina.
authors: Rodolfo H
authors: RH
authors: Acosta