Fabrication of Master
Conventionally, masters are fabricated using photolithography. Here, we use inexpensive, commercially-available CD/DVDs as masters. These masters will be used later to prepare PDMS stamps.
Cut the CD (the one used is Sony CD-R) with scissors. There is a polycarbonate (PC) surface underneath and a peelable Al layer. Some of them also have an acrylic layer on top of the Al layer and a label as the top-most surface.
Peel the Al layer off of the polycarbonate (PC) base using tweezers. Save both the Al layer and the PC surface for AFM imaging, placing both patterned side face-up in the petri dish. You can use either the PC surface or the Al layer as the master for soft lithography.
AFM (surface view) of the polycarbonate surface from a blank Sony CD-R
AFM of the Al foil (the surface that adheres to the polycarbonate)