Photolithography consists in insolating a photosensitive resin (or polymer) through a mask in order to produce microstructures on a flat substrate, which then serve as a mould for casting PDMS and obtain microfluidic chips after curing, piercing and sealing. Following the UV-exposition, the microstructures are developed into a solvent that dissolves the unexposed resin. This process leads under some circumstances to unexpected deposition on the substrate at the vicinity of the microstructures. These depositions are droplets of polymer ejected from the solvent at the contact line of the evaporating menisci formed at the edges of the microstructures. Could these deposition defects be used as a means to provide interesting surface properties? To answer this question and control the deposition, one needs to understand the mechanism underlying the ejection (or escape) of the polymer droplets out of its solvent. This is the purpose of this on-going work.
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