# Droplets capped with an elastic film can be round, elliptical, or nearly square

## TL;DR

This paper demonstrates how elastic film capping enables precise control over droplet shape and contact angle, allowing for tunable liquid lenses and innovative liquid patterning techniques.

## Contribution

It introduces a novel method of controlling droplet morphology through elastic boundary tension, enabling shape transformations from round to elliptical and nearly square.

## Key findings

- Droplet shape can be tuned from round to elliptical and nearly square.
- Adjusting elastic tension controls contact angle and droplet morphology.
- Potential applications include tunable liquid lenses and liquid patterning.

## Abstract

We present experiments which show that the partial wetting of droplets capped by taut elastic films is highly tunable. Adjusting the tension allows the contact angle and droplet morphology to be controlled. By exploiting these elastic boundaries, droplets can be made elliptical, with an adjustable aspect ratio, and can even be transformed into a nearly square shape. This system can be used to create tunable liquid lenses, and moreover, presents a unique approach to liquid patterning.