Next, a sample was placed in a Leica Ultracut UC7 cryo-microtome. The temperature inside the microtome chamber was lowered to -50 °C, i.e., well below the lowest glass transition temperature (5 °C). The sample was then initially roughly cut using a DiATOME trim 45° diamond knife. The finish cut, yielding sufficiently smooth sample surfaces for AFM measurements, was carried out with a DiATOME cryo 35° diamond knife.