PDMS stamps are pieces of Polydimethylsiloxane (PDMS)

Polydimethylsiloxane

Polydimethylsiloxane 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 properties. PDMS is optically clear, and, in general, is...

 that have been patterned usually against a master to form a relief pattern used in soft lithography

Soft lithography

200px|right|thumb|Figure 1 - "Inking" a stamp. PDMS stamp with pattern is placed in Ethanol and ODT solution200px|right|thumb|Figure 2 - ODT from the solution settles down onto the PDMS stamp. Stamp now has ODT attached to it which acts as the ink....

. This PDMS stamp can be used in either its current form as a relief surface for techniques such as Micro Contact Printing

Micro Contact Printing

Microcontact printing is a form of soft lithography that uses the relief patterns on a master Polydimethylsiloxane stamp to form patterns of self-assembled monolayers of ink on the surface of a substrate through conformal contact...

 or can also be attached to an external source by tubing so that liquid may be passed through channels on its surface. In this second case it will often be laminated to a surface so that chemistry can be performed on that surface producing a pattern of the PDMS stamp on to the surface. Alternatively a PDMS stamp can be laminated to a second piece of PDMS to form a contained device. It is possible to pattern PDMS with nanometre

Nanometre

A nanometre is a unit of length in the metric system, equal to one billionth of a metre. The name combines the SI prefix nano- with the parent unit name metre .The nanometre is often used to express dimensions on the atomic scale: the diameter...

 resolution. Many techniques have been developed to modify the basic setups to perform a range of tasks such as assays on small volumes. These kinds of devices are often referred to as microfluidic devices

Microfluidics

Microfluidics deals with the behavior, precise control and manipulation of fluids that are geometrically constrained to a small, typically sub-millimeter, scale.Typically, micro means one of the following features:* small volumes...

. Because of the small dimensions of these devices flow is laminar not turbulent which can lead to many useful properties; however, this reduces the ability of fluid streams to mix.