For this lab session we were divided in 2 groups. The materials were provided by the instructors.
• Gold-coated glass slides • mM solution of
octadecanethiol (CH3(CH2)17SH) in ethanol
• PDMS stamp • Filter paper
• Petri dishes • Nitrogen
• Deionized water
We started by preparing the octadecanethiol solution, by mistake we used 0,286g of octadecanethiol so we diluted in more ethanol.
It was quite difficult to mix so we tried first with the vortex machine and then with the sonic machine. The sonic machine was able to dissolve the octadecanethiol in the ethanol.
Once the solution was ready we dropped some solution with a pipette on some filter paper that we cut to be of the same shape as our PDMS stamp, we made sure that the filter paper was uniformly wet and then we placed it in a petri dish.
We took the PDMS stamp, pressed it on the wet filtered paper, then we blow dried the PDMS with nitrogen and then rinsed it with ethanol to distribute the octadecanethiol. After this we dried it again with nitrogen. We then cleaned the gold-coated glass with acetone and nitrogen and pressed the stamp against the golden surface for 1 minute. We then rinsed the gold-coated dish with deionized water to see the pattern (see fig.1). It was difficult to distinguish the pattern so we tried to blow on it with our mouths, this time the condensation on the surface showed a very clear pattern.