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Free keywords:
Self-assembled monolayers; Thiols; Microcontact printing; Sum frequency generation
Abstract:
Films of hexadecane thiol on gold prepared by contact printing with a stamp of polydimethylsiloxane were investigated by IR–VIS sum frequency generation (SFG), IR spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The contact time was up to 60 s and the pressure ranged from 1 to 6 bar. SFG, as a method directly sensitive to molecular conformation, reveals a significantly higher degree of disorder in stamped films compared to monolayers prepared by immersion. Correspondingly, contact angle measurements yield a lower advancing contact angle and a higher hysteresis. XPS analysis shows that residues of the stamping material are left on the surface.
