Heteroepitaxial growth on the air-solid interface: A large matching tolerance between nonpolar organic molecules on polar inorganic substrates

Abstract

Inspired by the crystallization/fibrillization of proteins/peptides on the liquid–solid interfaces, here we demonstrate a novel approach to create low dimensional crystals of nonpolar organic molecules on polar inorganic substrates by the heteroepitaxial growth means on the air–solid interface. Using physical evaporation deposition (PVD) on air–solid interfaces, paraffin as a model nonpolar molecule can epitaxially grow into patterned crystal nanostructures on a polar substrate mica (001). With the atomic force microscopy and the small angle diffraction of synchrotron radiation X-ray, we figure out that the hydrocarbon chain of paraffin is perpendicular to the atomic lattice of mica, and the heteroepitaxial growth is originated from a large tolerance of the distance matching between the adjacent silicon atoms on the surface of mica and the adjacent paraffin terminals inside its crystal nanostructure. This study cannot only fill up the gap for researching the heteroepitaxial crystallization of nonpolar organic molecules on polar inorganic substrates, but also demonstrates that the approach reported in this work holds potential for creating low-dimensional molecular crystals, nanopatterns and functional nanofilms.