title: Advances in modeling sorption and diffusion of moisture in porous reactive materials.
abstract: Water-vapor-uptake experiments were performed on a silica-filled poly(dimethylsiloxane) (PDMS) network and modeled by using two different approaches. The data was modeled by using established methods and the model parameters were used to predict moisture uptake in a sample. The predictions are reasonably good, but not outstanding; many of the shortcomings of the modeling are discussed. A high-fidelity modeling approach is derived and used to improve the modeling of moisture uptake and diffusion. Our modeling approach captures the physics and kinetics of diffusion and adsorption/desorption, simultaneously. It predicts uptake better than the established method; more importantly, it is also able to predict outgassing. The material used for these studies is a filled-PDMS network; physical interpretations concerning the sorption and diffusion of moisture in this network are discussed.
authors.affiliation: Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550-9698 (USA). harley2@llnl.gov.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Harley
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Glascoe
authors.forename: James P
authors.initials: JP
authors.lastname: Lewicki
authors.forename: Robert S
authors.initials: RS
authors.lastname: Maxwell
keywords: computational chemistry; diffusion; silicon; sorption; water chemistry