Question: is pdms hydrophilic or hydrophobic?
Answer: PDMS is a hydrophobic material (water contact angle >100°)6, which has consequences for droplet-based microfluidics. To successfully generate droplets, the continuous (i.e., external) phase needs to effectively wet the device walls; therefore, PDMS is ideally suited for the generation of water-in-oil (w/o) droplets7.