Three-Dimensional Spirals of Conjugated Block Copolymers Driven by Screw Dislocation

Abstract

Three-dimensional spiral structures are common in nature but rare in nanoscale or mesoscale objects formed by self-assembly, and it is a challenge to obtain uniform and well-structured 3D spiral architecture. Here, we present a simple approach to preparation of 3D spiral micelles with conjugated diblock copolymer poly(p-phenylenevinylene)-block-poly(ethyleneglycol) by a dissolution-cooling-aging process. By controlling the concentration of the growing solution, the size of micelles can be regulated, and the transformation of assembly morphology from 2D square to 3D spiral can be realized. In view of the low crystallinity of compounds in this system, the 3D spiral structure is driven by relatively weak π–π intermolecular interactions of the conjugated core of the block copolymers. The surface potential of these 3D micelles is almost equally dispersed among the different positions of the spirals from the Kelvin probe force microscopy experiments, and the conductivity of the 3D spiral is inversely proportional to the numbers of spiral layers. Based on their electrical response features, these 3D spiral architectures composed of conjugated block copolymers, especially with well-controlled nanoscale sizes, should be a very promising candidate for the future photoelectronic device and switch applications.