First-principles study of organically modified muscovite mica with ammonium (NH4+) or methylammonium (CH3NH3+) ion

• Published in: Journal of materials science Vol. 51; no. 24; pp. 10806 - 10818
• Main Authors: Yu, Chol-Jun, Choe, Song-Hyok, Jang, Yong-Man, Jang, Gwang-Hyok, Pae, Yong-Hyon
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.12.2016; Springer Nature B.V
• Subjects: Cation exchanging; Characterization and Evaluation of Materials; Chemical bonds; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Density functional theory; Electron density; Energy gap; Exothermic reactions; First principles; Interlayers; Materials Science; Mathematical analysis; Muscovite; Organic chemistry; Original Paper; Polymer Sciences; Solid Mechanics; Unit cell; Density Functional Theory Calculation; Tetrahedral Sheet; Generalize Gradient Approximation; Local Density Approximation; Interlayer Cation
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-016-0292-y

Using density functional theory calculations, we have investigated the interlayer cation exchange phenomena in muscovite mica, which is motivated by a necessity to develop flexible high-insulating covering materials. The crystalline structures, chemical bonding properties, energetics, and electronic properties of muscovites before and after exchange of interlayer K + cation with ammonium (NH 4 + ) or methylammonium (CH 3 NH 3 + ) ion were calculated. It was found that the unit cell volume changes are negligibly small upon exchange with NH 4 + ion, while the unit cells are expanded with about 4 % relative rate when replacing the interlayer K + cation with CH 3 NH 3 + ion. The energy band gap of pre-exchanged muscovite was calculated to be about 5 eV, which hardly changes upon interlayer cation exchange with either NH 4 + or CH 3 NH 3 + ion, indicating the preservation of high insulating property of muscovite. The exchange energies were found to be about –100 kJ/mol for NH 4 + and about –50 kJ/mol for CH 3 NH 3 + exchange, indicating that the exchange reactions are exothermic. A detailed analysis of atomic resolved density of states and electron density redistribution was provided.