PDMS 

Polydimethylsiloxane (PDMS) belongs to a group of polymeric organosilicon compounds that are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological (or flow) properties. It can be etched using Inductively Coupled Plasma (ICP) and Reactive Ion Etching (RIE).