Elastocapillary Wetting: Square Holes and Square Droplets

We present experiments examining wetting and dewetting of liquids capped by thin elastomeric films. In the dewetting experiments, increasing the isotropic tension of the capping elastomeric layer leads to flatter dewetting rims, and consequently, a slower dewetting speed. This result is consistent with an analogue experiment wherein partially wetting droplets are capped by thin elastic films, and increasing the tension decreases the contact angle. We show that using thin elastic films to cap a liquid presents a new avenue for patterning. By suitable choices of the elastic boundary conditions, holes and droplets can assume elliptical and square morphologies.