text: When depositing a droplet on a solid surface with contact angle θ, horizontal force balance is described by Young's equation. However, there is a vertical force balance which while often ignored can be written as:
  Where
   is the force per unit length in the vertical direction
    is the surface tension of a liquid
    is the Young's modulus of a substrate
   is deformation of the substrate
  This gives length scale  δ~ γ/E sin θ for the deformation of bulk materials caused by the surface tension force.
  For example, if a water ( ~ 72 mN/m) droplet is deposited on the glass ( ~ 700 GPa), this gives  ~10m which is typically negligible. However, if a water droplet is deposited on the PDMS (  ~ 300 kPa), this causes the deformation to be  ~10m, which is in micron scale. This can have great impact on micro/nanotechnology applications where length scale is comparable and "soft" photoresists are used.