Can Linear Conjugated Polymers Form Stable Helical Structures on the Carbon Nanotubes?

The formation mechanism of ordered helical structures of conjugated polymers wrapping onto single-walled carbon nanotubes (SWCNTs) has been full of controversy in recent decades. A formation mechanism is proposed for the linear conjugated polymers wrapping around SWCNTs that the formation of helical structures is dependent on the orientation competition between backbone segments and side groups via transmission electron microscopy observations and molecular dynamics simulations. Results show that the conjugated polymers cannot always form stable helical structures, even if they have the capability to form a stable helix. In fact, only part of polymer segments presents a stable helix on the SWCNTs for the internal rotation in polymer deformations. Furthermore, a design framework is proposed to choose specific conjugated homopolymers and copolymers which can form helical structures on the SWCNTs.