Pospísil Miroslav, Capková Pavla, Merínská Dagmar, Malác Zdenek, Simoník Josef
Faculty of Mathematics and Physics, Charles University Prague, Ke Karlovu 3, Prague 2, 121 16, Czech Republic
J Colloid Interface Sci. 2001 Apr 1;236(1):127-131. doi: 10.1006/jcis.2000.7360.
Molecular mechanics and molecular dynamics simulations combined with X-ray powder diffraction were used in structure investigation of montmorillonite intercalated with cetylpyridinium (CP) and cethyltrimethylammonium (CTA) cations. Molecular modeling revealed the interlayer structure and differences in intercalation behavior of CP and CTA cations in montmorillonite. The experimental and calculated values of basal spacing were in good agreement for both intercalates: in the case of CP-montmorillonite d(exp)=20.59 Å, d(calc)=20.60 Å; for CTA-montmorillonite d(exp)=18.00 Å and d(calc)=18.10 Å. CTA-montmorillonite exhibits significantly higher total sublimation energy and higher host-guest interaction energy than the CP-montmorillonite. The main difference between both intercalates is in charge distribution on the host layers and guest species. The charge transfer from the guest species to the host layer is higher in CTA-montmorillonite than in CP-montmorillonite, and consequently the charge polarization between the host and guest layers is much higher in CTA-montmorillonite. This leads to much stronger host-guest electrostatic interaction in the case of CTA-montmorillonite. Copyright 2001 Academic Press.
将分子力学和分子动力学模拟与X射线粉末衍射相结合，用于研究十六烷基吡啶（CP）和十六烷基三甲基铵（CTA）阳离子插层蒙脱石的结构。分子模拟揭示了蒙脱石中CP和CTA阳离子的层间结构及插层行为差异。两种插层物的基面间距实验值和计算值吻合良好：对于CP-蒙脱石，d(exp)=20.59 Å，d(calc)=20.60 Å；对于CTA-蒙脱石，d(exp)=18.00 Å，d(calc)=18.10 Å。CTA-蒙脱石的总升华能和主客体相互作用能显著高于CP-蒙脱石。两种插层物的主要区别在于主体层和客体物种上的电荷分布。CTA-蒙脱石中客体物种向主体层的电荷转移高于CP-蒙脱石，因此CTA-蒙脱石中主客体层之间的电荷极化程度更高。这导致CTA-蒙脱石中主客体静电相互作用更强。版权所有2001年学术出版社。
