Trioctahedral and dioctahedral organosmectites delaminate in 1-octanol to give stable monolayer colloidal dispersions. Addition of acetone to a mixture of these colloidal dispersions yields a composite of the two clays. Layers of the two smectites are interstratified in the composite. Due to random costacking of layers the thermal decomposition behavior of the composite is different from that of the parent smectites and their physical mixture. (c) 2008 Elsevier Inc. All rights reserved.