Conformational morphology of polyaniline grown on self-assembled monolayer modified silicon

Polyaniline (PANI) films with pyramidal shaped crystallites were prepared by self-organization on self-assembled monolayer (SAM) modified Si substrates. High-resolution atomic force microscopy (HR-AFM) shows that SAM has tridymite structural order and the PANI film has biphasic conformational morphology corresponding to face-on orientation and edge-on orientation. Order parameters obtained from power spectral density analysis of HR-AFM images of SAM and PANI films show that the pyramidal crystallites are in emeraldine salt (ES-I) form and the region between the crystallites is in emeraldine base (EB-II) form. The ordered lattice of PANI crystallites as observed by cross-sectional HR-TEM confirms its single crystalline nature as well as epitaxial growth. The heteroepitaxial growth of PANI is attributed to the structural order of interfacial SAM on Si.

► The structural order of self-assembled monolayer (SAM) on Si assists in hetero-epitaxial growth of polyaniline (PANI) films.
► The power spectral density (PSD) analysis of the high-resolution AFM images provides the order parameters, which help to elucidate the ordering in SAM and PANI films.
► PSD function could be used to analyze the high-resolution AFM images, which hitherto has been used mainly for low-resolution image analysis.
► The ordered lattice image and SAED pattern obtained by HR-TEM confirms the single crystalline nature of pyramidal crystallites and their epitaxial growth at the interface.