Self-Assembled Film Organization in Fast Microcontact Printing Investigated by Sum Frequency Generation Spectroscopy

The ability of microcontact printing to build highly ordered alkanethiol self-assembled monolayers (SAMs) on Pt substrates within a short time is studied by sum frequency generation (SFG) spectroscopy and contact angle measurements. The deposition of ordered hexadecanethiol and dodecanethiol monolayers onto platinum substrates is achieved in less than 1 s. The film order and the alkane chain orientation are deduced from the SFG fingerprint acquired under different sets of laser polarization. Comparisons between the SAMs prepared by printing or by immersion demonstrate that both methods lead to the same high quality organization. Patterning effects within printed films are also investigated with respect to the layer conformation. Finally, wetting properties of printed layers are correlated with the printing duration, corroborating the spectroscopic results.