Thermal Stability of MEHA and DT SAMs

For cleaning the bare Au(111) substrate prior to SAM deposition, the gold substrates were annealed in a furnace at 733 K for 4 h and immediately quenched in N₂-bubbled ethanol (EtOH) solvent. MEHA SAMs were prepared by immersion of the Au(111) substrate in a 0.01 mM EtOH solution of MEHA for a desired period (1 min, 10 min, and 1 h) at RT. A schematic view of the formation of MEHA SAMs through hydrogen bonding networks can be seen in Figure 1. The resulting MEHA SAMs on Au(111) were removed from solution, immediately rinsed with pure EtOH solvent, and dried with an N₂ stream. To compare the thermal stability of MEHA and DT on Au(111), pre-covered DT SAMs were also prepared after 1 h deposition in a 0.01 mM EtOH solution of DT. To compare the thermal stability of pre-covered MEHA and DT SAMs, both SAMs were annealed at 373 K for 1 h.