Understanding the Swelling Behavior of Modified Nanoclay Filler Particles in Water and Ethanol
journal contributionposted on 2015-06-04, 00:00 authored by Sebastian Metz, Richard L. Anderson, Dawn L. Geatches, James L. Suter, Robert Lines, H. Chris Greenwell
Clay–polymer nanocomposite materials have gained much attention owing to their low weight ratio of filler to reinforcement properties, delivering lightweight yet resilient materials with excellent barrier properties to gas diffusion. An important process in their production is clay exfoliation, as maximum reinforcement and improvement of barrier properties occur when the clay mineral platelets are fully separated and dispersed through the polymer matrix with a preferred orientation. In this study we examine clay swellingthe first step leading to exfoliationusing molecular dynamics to generate solvation energetics, swelling curves, and atomic density profiles of three types of clay mineralsmontmorillonite, vermiculite, and hectoritewith interlayer Na+ cations and/or three quaternary ammonium surfactants in water and ethanol. Analysis based on the provided simulations can help to distinguish between favorable and unfavorable swelling profiles of mineral/surfactant/solvent systems and therefore guide further research into this complex field.