Moreover, Segalman and coworkers found that the film structures of PPV-b-PI had a gradual reorientation from parallel to perpendicular orientation accompanied by a transition of the bulk film to a polycrystalline bimodally oriented structure with increasing the film thickness [117]. Hadziioannou and coworkers synthesized a series of fullerene-grafted rod (DEH-PPV)-coil block copolymers as a candidate active layer in photovoltaic devices [36]. For the fullerene-free copolymer with a sufficiently low rod–coil weight fraction, the coil block destabilized considerably the rod–rod interactions and led to a lamellar phase with the rod block being in a liquid-crystalline state at room temperature ( Fig. 29(a)). On the other hand, microphase separation enhanced the interlamellar ordering. The results also showed either monolayer or double-layer lamellae were formed, depending on the copolymer molecular structure. However, adding the fullerene moieties considerably affected the polymer self-assembly through the growth of fullerene nanocrystals ( Fig. 29(b))