Microcontact printing is a well-known tool for the replication of small features. The state of the art is the development of structures in dimensions of some hundreds of nanometers. A variety of problems are encountered upon approaching the 100 nm scale. Diffusion processes appear to be responsible for the unsharpness of the replicated structures. We try to overcome this problem by the application less volatile sulfur compounds which still provide monolayers, such as thioether-modified calixarenes.
The presented results give a comparison of the resistance of monolayers of decanethiol, didecylsulfide, and a thioether-modified calixarene to a cyanide etchant. It is shown that the thiol and the calixarene monolayers are stable against the etchant, whereas self-assembled monolayer (SAMs), made of didecylsulfide, showed significant changes in their electrochemical behavior. Using SAMs of decanethiol, the electrochemical resistivity dropped from 63.48 kOhm to 8.70 kOhm after 30 min etching. Similar results were obtained for the thioether-modified calixarene. In contrast, the influence of the etchant on didecylsulfide monolayers is more significant (resistance of etched layers: 0.248 kOhm). We found that SAMs, made of calixarenes, are as resistant as decanethiol SAMs to the cyanide etchant. These results are confirmed by measuring the capacitance, the heterogeneous electron transfer, and by contact angle measurements.