Dipole-Induced, Thermally Stable Lamellar Structure by Polar Aromatic Silane

Abstract

Controlled self-assembly of polar aromatic silane leads to the formation of well-ordered lamellar structures. Graphite-like features are clearly visible with a scanning electron microscope (SEM). In addition, X-ray diffraction (XRD) patterns suggest a d spacing of 14.28 A along the z-axis and 4.42 A in the xy plane, which all agree with theoretical modeling. Constructing multistacks of silane molecules with a high degree of ordering is a daunting task. Amorphous monolayers are frequently reported. Aggravated van der Waals interaction, pi-pi electron overlapping, and solvophobic interactions can all lead to the formation of multistacks. The importance of a dipole to the ordered stacking is essentially unknown. This work suggests that a strong dipole-dipole interaction can be another important driving force in forming lamellar structures. The resulting large electrostatic interactions between the dipole and water provide an excellent thermal stability for these lamellas up to 350 degrees C. Organized, layered structures with a permanent dipole can be used in piezoelectric devices or as active surfaces to bind polar molecules, such as toxic gas, methanol, or DNA.