We define the relative interphase thickness as (λphase /aFF) to compare the data series obtained with different probe radii and different I layer thicknesses. Figure shows a composite of all modulus-distance profiles. If (λphase /aFF) is less than 2, then the (E/EFF) profile follows the prediction of the master curve obtained from FEA. With increasing (λphase /aFF) the modulus profiles increasingly differ from the modulus profiles of the master curve. In these cases, the (E/EFF-EMC) profiles show clear evidence of the I layer, as seen in the inset of Figure . As visualized by the color scale in Figure , the evidence of the interphase becomes more obvious with higher (λphase /aFF), regardless of specific probe radii and I layer thickness. This result shows that the ratio of (λphase /aFF) characterizes the modulus-distance profiles and supports our choice of dimensionless analysis for the determination of interphase thickness. between master curve and normalized modulus profile (E/EFF-EMC). All profiles lined up with the order of (λphase /aFF), as higher λphase /aFF shows larger difference from master curve. This result show that the ratio of λphase /aFF characterizes the modulus -distance profile and thus provide the rational of dimensionless analysis.