We created five samples prepared with different concentrations of the interphase materials, and therefore different interphase thicknesses, (Cint = 2.5, 5, 10, and 20 wt.%) and a control sample without an interphase. In each sample, the interphase thickness obtained from phase map analysis (λphase) is summarized in Table which is assumed to be the ground truth. Since the phase imaging applies much less force compared to the Fast Force Mapping, the contact radius of the measurement is minimized and therefore, as we will show later, convolution of material and tip effects is minimized.