PDMS, or poly(dimethysiloxane) is a commercially available type of silicon rubber. PDMS has a wide range of applications. It is currently used as a master stamp in soft lithography, as the mechanical interconnection layer between two silicon wafers, as ion selective membranes on ISFETs, and as a spring material in MEMs accelerometers.

PDMS Stamp Edit

PDMS is commonly used as the master stamp in soft lithography. PDMS is used as the stamp because it has many useful properties for this application. These properties include; PDMS is chemically inert to many of the materials being patterned by soft lithography, PDMS has relatively low surface free energy (γ = 21.6 dyn/cm³) which allows for the stamp to release from the printed structures, PDMS is optically transparent down to roughly 300nm which allows for ultra violet curing in UV-molding, PDMS is physically strong (tensile modulus = 4.77 MPa) and PDMS is flexible (elastic modulus = 1.8 MPa and elongation of up to 160%).g

References Edit

  • Lotters, J. C.; Olthuis, W.; Veltink, P. H.; Bergveld, P. "The mechanical properties of the rubber elastic polymer polydimethylsiloxane for sensor applications" J Micromech Microeng 1997, 7, (3), 145-147.
  • Gates B.D., Xu Q., Love J. C., Wolfe D. B., Whitesides G. M., “Unconventional Nanofabrication”, Annu. Rev. Mater. Res., Vol. 34, pp.339-72, 2004.