Analysis and simulations on the structure of sulfanilic acid zwitterion intercalated hydrotalcite and montmorillonite

A new type of bipolar lamellar complex intercalated material was synthesized by assembling the layers of delaminated hydrotalcite (LDHs) and montmorillonite (MMT) with sulfanilic acid zwitterions (ABS). The complex layered structure and composition of the intercalated compounds ABS–LDHs–MMT were directly or indirectly revealed by XRD, IR, SEM and TEM. Based on the experimental results, a theoretical structural model of the ABS–LDHs–MMT complex was established and optimized by means of quantum chemistry and molecular simulation methods. The computed crystal lattice parameters of ABS–LDHs–MMT were in accordance with the measured XRD data of complexes. Two kinds of special conformations with different orientations of intercalated ions were proposed by comparing the experimental data and simulation results of XRD patterns. The frontier molecular orbital (HOMO and LUMO) and partial density of states (PDOS) analysis of the complex structure displayed that the interactions between the layers and intercalated ions of the complex were mainly induced by hydrogen bonds.