Surface potentials of patterned organosilane self-assembled monolayers acquired by Kelvin probe force microscopy and ab initio molecular calculation

This study aimed experimentally and theoretically to reveal the surface potentials of organosilane self-assembled monolayers (SAMs) using Kelvin probe force microscopy (KPFM) and ab initio molecular orbital (MO) calculations, and to distinguish among the surface domains of the SAMs. We prepared the patterned SAMs of n-octadecyltrimethoxysilane [ODS: H3C(CH2)17Si(OCH3)3], heptadecafluoro-1,1,2,2-tetrahydro-decyl-1-trimethoxysilane [FAS: F3C(CF2)7(CH2)2Si(OCH3)3] and n-(6-aminohexyl)aminopropyltrimethoxysilane [AHAPS: H2N(CH2)6NH(CH2)3Si(OCH3)3] by chemical vapor deposition (CVD). The surface potentials for FAS-SAM and AHAPS-SAM vs. ODS-SAM in the atmosphere were −170 and +50 mV, respectively. The experimental surface potentials agreed with the calculated ones at the surface area occupied by a molecule of 1.1–1.5 nm2 molecule−1.