| Uses |
Silicones are polymeric materials having silicon and oxygen on their composition. They are largely inert compounds usually heat-resistant, nonstick, and rubberlike. Polydimethylsiloxane (PDMS, molecular formula (C2H6OSi)n, density 965 kg/m3, boiling point: < 200℃, shear modulus between 100 kPa and 3 MPa, loss tangent less than 0.001) is a viscoelastic polymer (elastomer). PDMS is widely used in microfluidic technology thanks to some of its unique properties: it is low cost, nontoxic, chemically resistant, and stable against humidity and temperature variations. PDMS also presents low interfacial energy, which allows it to avoid chemical interactions with other polymers and solutions in the microfluidic channels. After polymerization and cross-linking, solid PDMS presents hydrophobic surface. A treatment using plasma oxidation is frequently used to alter the surface chemistry by adding silanol (SiOH) groups to the surface terminations and make the surface hydrophilic (wettable). PDMS is usually used as sealant, structural microchannel material or elastomer stamping matrix in soft lithography techniques like microcontact printing and micromolding.
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