Adsorption-induced deformation of mesoporous solids

Area of Science:

• Physical Chemistry
• Materials Science
• Surface Science

Background:

• Mesoporous solids exhibit complex deformation during adsorption-desorption cycles.
• Capillary condensation within pores leads to significant structural changes.
• Understanding these deformations is crucial for material stability and performance.

Purpose of the Study:

• To develop a thermodynamic model for mesoporous solid deformation during capillary condensation.
• To relate mechanical stress from adsorbed phases to adsorption isotherms.
• To provide a parameter-free description of nonmonotonic hysteretic deformation.

Main Methods:

• Application of the Derjaguin-Broekhoff-de Boer theory.
• Development of a thermodynamic model linking solvation pressure and adsorption.
• Derivation of analytical expressions for solvation pressure dependence on vapor pressure.

Main Results:

• A novel thermodynamic model for adsorption-induced deformation was proposed.
• Analytical expressions accurately describe solvation pressure changes.
• The model successfully explains nonmonotonic hysteretic deformation without adjustable parameters.

Conclusions:

• The proposed model offers a robust, parameter-free approach to understanding mesoporous solid deformation.
• It accurately predicts experimental adsorption deformation data for porous glass and SBA-15 silica.
• This work advances the understanding of capillary condensation effects in porous materials.