Nanoscale Islands of the Self Assembled Monolayer of Alkanethiol

Abstract

Department of Chemistry, Chungbuk National University, Cheongju 361-763, KoreaReceived September 21, 2013, Accepted September 27, 2013Molecular dynamics simulations were performed to study the structure and stability of a nanoscale self-assembled monolayer (SAM) of alkanethiol on a gold (111) surface. The tilt angle and orientational order ofthe alkyl chains in the SAM island were examined by systematically varying the size of the island. The chainlength dependence of the SAM island was examined by considering alkanethiols containing 12, 16, 20, and 24carbon atoms. The minimum diameter of SAM islands made from 1-tetracosanethiol, 1-ecosanethiol, 1-hexadecanethiol and 1-dodecanethiol were 2.29, 1.9, 4.7 and 4.76 nm, respectively. These set the ultimateresolution that can be patterned by soft nanolithography. As the length of alkanethiol increases, the SAMislands became more ordered in both orientation and conformation of the alkyl chains. Key Words : Self-assembled monolayer, Alkanethiol, Chain length, NanolithographyIntroductionThe self-assembled monolayers (SAMs) of alkanethiolhave numerous applications as coating materials.