Quantitative 3D measurement of the nanostructural features that dictate mesoscale performance properties of nanocomposites

Mesoscale performance properties of nanocomposites are dictated by the nanoscale structure developed in the composite during processing, combining nanoscale contributions over a mesoscale volume. In this artilce, for the first time, we present a procedure that deduces the fully 3D process-induced nanostructural features of carbon nanofiber/polymer composites responsible for the mesoscale performance. In particular, we have developed a method for obtaining the nanofiber orientation in 3D Euclidean space from 2D projections provided by a transmission electron microscope. The 3D Euler angles we obtain are used to construct orientation tensors, the measure of nanostructure that has the most significant influence on mesoscale performance properties. Our measurement method is benchmarked by using numerically generated 3D samples to compare orientation tensor components known a priori with those generated using our procedure. A significant contribution of the procedure is its ability to produce quantitative 3D measurements of the evolution of nanostructure in space and time. The method is successfully applied to observe the effect of extensional rheology on nanofiber orientation. It is shown that orientation tensor data obtained from our experimental method accurately fits the predictions of the fiber orientation evolution equation proposed by Folgar and Tucker. POLYM. COMPOS., 31:1495–1503, 2010. © 2009 Society of Plastics Engineers