Simulation study of intercalation complexes of kaolinite with simple amides as primary intercalation reagents

Abstract Delamination/exfoliation of book-like kaolinite particles is one of the most promising ways to produce aluminosilicate nanoscrolls. For the delamination of the kaolinite layers, multi-step intercalation/deintercalation procedures are used. In the first, direct intercalation step, the intercalation reagents are typically small organic molecules possessing high dipole moment. We modeled, evaluated and compared the incorporation features of formamide, urea and N-methylformamide molecules into the interlayer space of kaolinite by classical molecular simulations using realistic CHARMM-based atomic force fields. Besides the determination of characteristic basal spacings of the intercalation complexes, we compared the density and orientation distributions of the guest molecules, as well as atomic pair correlation functions. From the simulations we also calculated the typical intermolecular interaction energies and estimated the translational mobility of the different substances. Our results show that urea has some preference over the other substances in multi-step, heat-treating intercalation/deintercalation procedures with kaolinite.