See the below link for documentation.

https://github.com/ydsumith/Achilles-Contact-Angle/wiki

Version 2.0

The second version of Achilles is released with the support for any number of atom types.
Now, the droplets can be a mixture of different atoms, molecules, hydrocarbons etc.
So is the case with solid substrate. It can be plain platinum plate or can be SiO2 or amorphous alloys.