Molecular order and disorder of surfactants in clay nanocomposites.

Disorder of intercalated surfactant molecules in clay minerals causes gradual swelling, rather than commonly assumed swelling in discrete steps.

Hysteresis in clay swelling induced by hydrogen bonding: accurate prediction of swelling states.

We perform grand-canonical molecular simulations to study the molecular mechanism of clay swelling hysteresis as a function of the relative humidity. In particular, we focus on the transition from the one- to the two-layer hydrate and the influence of three types of counterions (Li+, Na+, and K+). Our results cover the experimental relative humidity region where swelling and shrinking usually occur.