DIRECT MEASUREMENT OF SOLVATION FORCES IN COMPLEX MICROPOROUS MEDIA -A NEW CHARACTERIZATION TOOL

We present a new beam bending (BB) technique for measuring solvation f orces in complex microporous materials. The solvation forces are compr essive and monotonically increasing with relative pressure. This is in stark contrast to Laplace-Kelvin theory (LKT) which predicts only ten sile stresses. Applying a nonlocal density functional theory (DFT), th e observed monotonic, compressive stresses are shown to arise from mol ecular sized pores with modest pore size polydispersity where the half -width of the distribution is 0.2-0.7 nm. Finally, the combined BB/DFT analysis provides a novel and much needed method for characterizing t he morphology of microporous thin film materials to 0.1 nm resolution.