Ra. Cairncross et al., PORE EVOLUTION AND SOLVENT TRANSPORT DURING DRYING OF GELLED SOL-GEL COATINGS - PREDICTING SPRINGBACK, Drying technology, 15(6-8), 1997, pp. 1815-1825
This paper reports predictions of drying phenomena in deformable porou
s gel coatings (i.e. a porous solid elastic network filled with air or
solvent). Initially, a gelled coating is saturated with solvent, but
as it dries, liquid-vapor menisci begin to recede into larger pores an
d the gel becomes a partially-saturated porous medium. The tensile cap
illary pressure in the liquid causes a compressive deformation on the
solid skeleton and a consequent reduction in thickness and pore-size o
f the coating. A theory coupling the large deformation of the solid sk
eleton to capillary pressure in the interstitial liquid is used to pre
dict the course of drying of dip-coated porous gel coatings. The theor
y predicts a 'springback' effect in late stages of drying as the effec
ts of capillary pressure diminish, which matches with experimental obs
ervations.