Molecular transfer and transport in noncovalent microcontact printing

Microcontact printing is commonly used to create patterned films of molecules covalently bonded to substrates (e.g., thiols on gold). Here we describe microcontact printing of several types of noncovalently bonding molecules on mica. Due to the weaker interaction of the molecules with the substrate, environmental factors such as temperature and relative humidity play an important role. The vapor pressure of the inks also had a large impact on the fidelity of the stamped patterns. Fingering instabilities were observed for monolayers of octadecanol, docosanol, stearylamine, and stearic acid stamped at moderate relative humidity. The fidelity of the stamped pattern generally increased with the headgroup-surface interaction strength. These stamped monolayer films shed light on molecular transfer and two-dimensional spreading mechanisms.