Phase Segregation in the Mixed Alkyl Thiol Self‐assembled Monolayers on a Gold Surface at a High Incubation Temperature in a Sealed Container

Abstract

Self-assembled monolayers (SAMs) of mixed 1-octanethiol (OT) and 1-decanethiol (DT) that were formed on gold substrates at a high incubation temperature in a sealed container were characterized using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). In mixed-composition monolayer films, self-assembly of the mixture could induce phase separation into discrete molecular domains at higher incubation temperatures. Mixtures of the alkanethiol molecules affected the domain size, defect density, packing density, and binding features of the resultant SAMs prepared on gold substrates. Single-moleculeresolved STM images of mixed SAMs revealed both c(4 × 2) − ns (non-shifted) for DT and c(4 × 2) − s (shifted) for OT domains. For the mixed SAMs, the peak S2 (XPS) increased in intensity relative to the peak S1, reflecting significant modifications in the binding characteristics of the thiols and surface roughness upon mixing.

Real-time kinetic analysis and detection of glycated hemoglobin A1c using a quartz crystal microbalance-based aptasensor

“…These observed particles could be correlated with the size of DNA aptamers, as similarly reported in previous studies. 32–34 After the HbA1c binding (Fig. 4c), particles with a height of about 4 nm were detected, which could be inferred to be the size of the HbA1c proteins.…”

“…A previous study suggested that the mixture of these compounds should be homogenized under sonication before use. 32,33 Fig. S2c † clearly shows that the ultrasonic pretreatment of the alkanethiol mixture for 1 min before SAM formation signicantly improved the surface distribution of MHDA molecules with the persistence of a few particles.…”