The contact angle of water and hexadace inside the channel was used to calculate the surface energy of the PDMS channel wall. For water and hexadecane, these angles were obtained as For Water -PDMS system Ecoflex is a soft silicone elastomer, manufactured and sold by Smooth-On Inc. It is prepared by mixing two different liquids in equal weight proportion and by crosslinking the mix at room temperature for four hours. To estimate the elastic modulus of Ecoflex, the pre-polymer solution was cross-linked inside a hollow cylindrical mould (capillary tube) with a circular cross-section to create rods with a diameter of 1.17 mm. These rods were subjected to a cantilever beam experiment, in which one end of a rod was secured to a rigid support and the deflection of the free end under gravity was observed. To estimate the modulus ( E ), slope of