During imaging, the peak-force frequency was 2 kHz and line rates were on the order of 1 Hz whilst recording 256-512 pixels/line. The vertical scan limit was reduced to 1 µm. Images were processed using Gwyddion for line by line flattening using a second order polynomial to remove tilt and bow in the samples. Images were filtered using a 2 pixel Gaussian filter at resolutions of 1.3 nm/pixel or less to remove high frequency noise. Figure was cropped to make Figure .