The present invention provides a nano-composite comprising a clay and a cationic mediator comprised of a hydrophobic unit and a cationic unit. The clay is exfoliated or intercalated by the cationic mediator. The present invention further provides a polymer formulation comprising the nano-composite. The nano-composite is practically useful in formulating compositions such as rubber and tire products with improved and well-balanced properties including gas permeability, cure properties, and/or mechanical properties etc.