Refractive index database

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Optical constants of (C2H6OSi)n (Polydimethylsiloxane, PDMS)
Schneider et al. 2009: Sylgard 184; n 0.35–0.70 µm

Wavelength: µm

Complex refractive index (n+ik)[ i ]

n   k   LogX   LogY   eV

Derived optical constants

Dispersion formula [ i ]



Sylgard 184 (Dow)


F. Schneider, J. Draheim, R. Kamberger, U. Wallrabe. Process and material properties of polydimethylsiloxane (PDMS) for Optical MEMS, Sens. Actuators A Phys. 151, 95-99 (2009)


[Expressions for n]   [CSV - comma separated]   [TXT - tab separated]   [Full database record]


Polydimethylsiloxane, (C2H6OSi)n

Polydimethylsiloxane (PDMS, (C2H6OSi)n) is a widely utilized silicon-based organic polymer known for its unique rheological properties. Characterized by its clear, viscous appearance, PDMS is optically transparent, rendering it particularly suitable for various optical applications. This elastomer exhibits a range of beneficial attributes: it's non-toxic, chemically inert, non-flammable, and resistant to ultraviolet radiation and ozone. Additionally, it is hydrophobic, meaning it repels water, and possesses excellent dielectric properties over a broad frequency range. These characteristics make PDMS an ideal choice for a multitude of applications, ranging from household products like shampoos and caulking to medical devices and microfluidic chips. In the realm of optics, the material's transparency across a broad spectrum combined with its flexibility has led to its use in soft lithography processes, waveguides, and even in the fabrication of flexible optical devices. The refractive properties of PDMS derive from its siloxane backbone, which imparts the material with its distinct optical and mechanical characteristics.

Other names

  • PDMS
  • Poly(dimethylsiloxane)
  • Dimethicone
  • Dimethylpolysiloxane

Food additive code

  • E900


  • SF-96 (Momentive)
  • RTV 615 (Momentive)
  • Sylgard 184 (Dow)

External links