Hi Andreas,

Self-assembled organothiolate monolayers can be removed from gold surfaces by applying H2 plasma. Compare "Removal of self-assembled monolayers of alkanethiolates on gold by plasma cleaning" (Surface Science, DOI 10.1016/j.susc.2005.07.038). Organothiols other than alkanethiols (e.g. with aromatic moieties) sometimes are tricky and cannot be fully removed by H2 plasma. Here, the following method can be used: 1) immerse the gold surface with the SAM into a solution of a long-chained n-alkylthiol (e.g. oktadecanethiol). The alkylthiols will replace the original SAM. 2) Use H2-plasma to remove the alkylthiolate-SAM.

Regards

Martin.

Hello Martin

Thanks for your help. So I guess that means the sulphur does stay after our cleaning. We do not use H2 plasma, only methods involving reactive oxygen.

Hi Andreas,

the use of reactive oxygen (eg., oxygen plasma) results in oxidized sulfur compounds on the surface and oxidizes the gold itself (according to the source given above). H2 plasma is clearly the better method to remove thiolate SAMs from gold surfaces.

Regards

Martin.