Synthesis, molecular dynamics and dielectric properties of benzoic acid intercalated kaolinite

Abstract

The synthesis of new clay-organic nanocomposites with potential application value is one of the research hotspots in the field of functional materials. Herein, benzoic acid intercalated kaolinite compound (K-BzCOOH, calculated as Al 2 Si 2 O 5 (OH) 4 ·(BzCOOH) 0.556 , d (001) of 1.419 nm, and 51.5% intercalation rate) was synthesized, and its preparation methods, intercalation mechanisms and dielectric properties were investigated thoroughly. The results show that K-BzCOOH must be obtained under high pressure with K-DMSO as the precursor and methanol as the solvent. The benzoic acid molecules are arranged in an inclined monolayer between kaolinite layers, and benzene ring and the center of gravity of benzoic acid molecules are close to the surface of alumina layer. Hydrogen bonds are mainly present between H(Al-sheet) and O(c=o), and between H(coo-h) and O(Si-sheet).The interfacial interaction between inorganic and organic components is -47.11 kJ/mol. Dielectric measurements show that K-BzCOOH exhibits relaxation behavior in the range of 1-10 7 Hz and 10-100°C, attributed to the limited dipole motion of benzoic acid molecules under the action of external electric field. Also, the compound has a low dielectric constant at frequencies greater than 10 6 Hz (6.9 and 8.8 at 10°C and 100°C, respectively), which can be considered as a low- k material for semiconductor industry. • K-BzCOOH (Al 2 Si 2 O 5 (OH) 4 ·(BzCOOH) 0.556 ) was first prepared. • Intercalation mechanism probed by molecular dynamics. • K-BzCOOH exhibits two dielectric relaxation processes and low dielectric constant.