Thank you for reading my question.
Now I try to make hydrophobic surfaces on the 3D printed resin substrate.
I would like to use 1-octanethiol to induce SAM (Self-Assembly Mono layer) after sputtering gold coating on the 3D printed resin substrate.
First I tried, Au sputtering on the substrate, and dip it into thiol. But the outcome is not clear hydrophobic surface, it is so sticky.
Is there anyone who can explain the procedure how to coat thiol?
Thank you.
If you want to favour the thiol-Au interaction, you need:
1. first, oxidize the top surface of gold, eg treating it in piranha solution,
2. afterthat, expose the oxidized gold surface to thiol-terminated molecules in an alcaline environment (if possible)
However, the experiment should be properly tailored to assure also lateral interaction among the already grafted (on Au) molecules to allow SAM formation.
Gun Oh
A monolayer on a substrate is obtained by the Lagmuir-Blodget method. To do this, it is necessary to lower a plate covered with gold into a solution with a gaseous (rarefied) monolayer of octanethiol. Then press the monolayer with barriers until the monolayer is in a condensed state. After that, gradually remove the plate from the water with a monolayer. Dry the plate.
Hi Gun Oh,
Maybe it's a post-synthesis purification issue. I was intrigued by the statement.".. it is so sticky ". Maybe som 1-octanethiol remained in the porous surface. I work sometimes with low molecular weight thiols and then purge everything very thoroughly with ethanol. What do you use as a solvent for 1-octanethiol? do you dip the plate directly into this compound (it's a solid?) . Mentioned by Prof. Yuri Mirgorod L-B method would probably also help but it requires a device to obtain a properly compressed layer.