Self-Assembled 3D Helical Hollow Superstructures with Enhanced Microwave Absorption Properties

Helical structures at different scales endow functional materials with special optical, electrical, and magnetic properties. However, methods for constructing and regulating single-handed helicity, particularly complex 3D hierarchical structures, remain limited. In this study, co-self-assembly process combined with emulsion droplets is used to produce the various well-defined 3D hollow superstructures of conducting polyaniline (PANI) with single-handed helicity. The chirality of PANI is induced using enantiomeric r- or s-camphorsulfonic acid as a dopant; the chirality of the dopant is then transferred to the supramolecular chirality of PANI assemblies and consequently to the helicity of 3D superstructures by incorporating emulsion droplets to serve collectively as soft templates. The twisting and anisotropism of these superstructures vary with the enhancement of the supramolecular chirality and result in the transformation of their morphologies from seashell-like to spindle-like and their cavity becoming more slender than their original shape. Due to the supramolecular chirality and hierarchical characteristics of these superstructures, enhanced microwave absorption performance is observed under a filler content of as low as 20 wt%, suggesting their promising application as microwave absorbers.