Block copolymer nanostructures such as nanosheets, nanoribbons, and nanotubes, are provided. The nanotructures are formed by the self-assembly of block copolymers during evaporation of solvent from a sol that has been “disturbed”, either i) internally by the introduction of relief (e.g. curvature) and/or the inclusion of nanoparticles in the sol; or ii) externally, e.g. by physical deformation of a semi-solid form of the sol, or a combination of internal and external disturbance. The nanostructures have uses in, for example, energy devices, electronics, sensors and drug delivery applications.