To make the membrane, the team created a layer of polyvinyl alcohol on a stiff silicon wafer. On top of the polyvinyl alcohol goes a layer of parylene, then layers acting as a semiconductor and other components of a thin-film transistor. In some experiments, the team put a sensor on the parylene layer that measured the strain the layer underwent when bent. Finally, the team stuck the whole silicon chip in water. The polyvinyl alcohol dissolved, separating the membrane from its silicon backing.