“…A variety of directing strategies, such as chemoepitaxy [3,4], graphoepitaxy [5,6], and pre-patterns that combine both chemo and graphoepitaxy [7], have been demonstrated. While BCP thin films are generally addressed as 2D patterning layers, BCP are inherently three dimensional (3D) materials, and even in extremely thin film, where the film thickness is smaller than the BCP periodicity (L 0 ), 3D structures can be found [8]. Indeed recent investigations using X-ray scattering [9,10], transmission electron microscopy (TEM) [8,11], and molecular simulations [12,13] have shed light on the three-dimensional structures that form in DSA films.…”