Steady self-scrolling of graphene sheets upon the solvation status of adsorbed polyhexylthiophene

Upon the tuning of solvent composition, the unfavorable solvation of adsorbed polyhexylthiophene is found able to drive graphene sheets to scroll steadily in solutions, resulting in nanoscrolls with a central void and regular stacking of internal layers. For theses steadily evolved graphene nanoscrolls, the interlayer distance is subject to the average radius of adsorbed molecular coils and the bending rigidity of graphene hexagonal structural units restricts the reachable curvature of central voids. When the unfavorable solvation is progressively lessened upon slow crystallization of adsorbed polyhexylthiophene molecules, the reverse unwrapping ensues accordingly. On the other hand, the solvent evaporation initiates the dense growth of crystalline whiskers outward from graphene nanoscrolls and thus results in comb-like superstructures. With mutual impingement effects associated with present superstructures, oriented assembly and growth behaviors of crystalline whiskers are able to occur, creating nematic fields of crystalline whiskers.