The lateral scan range was chosen to cover major parts of the freestanding membrane and sections of the substrate. Negative differential pressures in the range between 0.1 kPa and 6 kPa were applied to the membranes in ascending and descending order. The increments were 100 Pa between 0.1-1 kPa, 200 Pa between 1-3 kPa, and 300 Pa between 3-6 kPa. The same increments in the respective pressure ranges were applied for descending the pressure from 6 kPa to 0.1 kPa. For burst experiments, the increments to 6 kPa were kept the same, but they were increased to 1 kPa between 6-10 kPa, 2 kPa between 10-40 kPa and reduced again to 1 kPa between 40-85 kPa. The pressure was controlled using three pressure gauges (Sensortechnics, HDIB001DBF8P5 -100-100kPa, HDIM100DUF8P5 0-10kPa, HDIM010DUF8P5 0-1kPa). Data of the AFM bulge tests were evaluated using the spherical cap model of a thin-walled pressure vessel. Actuator Tests. The actuator tests were performed with the same setup described in our previous study using the AFM (JPK Nanowizard 3 equipped with ACTA-50 cantilevers) to detect the deflection of the hybrid membrane. The AFM was operated in intermittent contact mode, and the deflection was mea-sured as a function of time at fixed x,y-coordinates. Voltages of up to ±40 V were applied to the membrane with incremental step sizes of 2 V using a Keithley 2601A source measure unit. Each voltage was maintained for 2 s followed by 4 s at 0 V. The actuator tests were repeated to measure the membrane's deflection at different positions on the freestanding membrane.