The material properties and thickness of the interphase must be characterized to better understand nanocomposites. The composite samples analyzed in this work consist of carbon nanotubes (CNT), carbon fiber, and epoxy. The interphase describes the interaction between the carbon nanotubes and the epoxy. Measurements of interphase modulus and thickness are made using PeakForce QNM atomic force microscopy (AFM) at different points along the longitudinal axis of the CNT/epoxy interphase. The results of this work will help build a more accurate model of nanocomposites allowing for the use of nanocomposites in industries such as aerospace, energy and many more.