Diffusion of thiols during microcontact printing with rigid stamps

In this work we investigated the diffusion of thiol molecules during microcontact printing (@mCP) with rigid stamps - a process we call reversal @mCP. We use such stamps instead of soft polydimethylsiloxane (PDMS) stamps to overcome the problems of sagging and pairing of structures and deformation. We varied thiol concentration in ethanol as well as different contact times. It shows that the lower the concentration the thinner the lines and the longer the contact time the thicker the lines until saturation is reached. Working in this saturation region overcomes the problem of the strong dependency of line width over contact time which is usually observed in microcontact printing and which restricts the reproducibility of the process itself. Gold lines with a width down to 80nm have been achieved using this novel method.