Tunable Chiral Plasmonic Activities Enabled via Stimuli Responsive Micro-Origami.

Chiral plasmonic nanomaterials with distinctive circularly polarized light-dependent optical response over broad range of frequency have great potential for photonic and biomedical applications. However, it still remains challenging to fabricate 3D plasmonic chiral micro-constructs with readily modulated chiroptical properties over the magnitude of ellipticity, mode frequency and switchable handedness, especially in the visible to near-infrared range. In this study, polymeric micro-origami based 3D plasmonic chiral structures are constructed through self-rolling of gold nanoparticles (AuNS)-decorated polymeric micro-sheets. Spherical AuNSs are assembled as highly ordered linear chains on 2D rectangular micro-sheets by polydimethylsiloxane-wrinkle assisted assembly. Upon rolling the micro-sheets to micro-tubules, the AuNS chains transform into 3D helices. The AuNS assembled helices induce collective plasmonic modes propagating in a helical manner, leading to strong chiral response over Vis-NIR range. The circular dichroism (CD) is measured to be as high as hundreds millidegree, and the position and sign of CD peaks are actively modulated by controlling the orientated angle of AuNS chains, enabled by tuning the collective plasmonic modes. This micro-origami based strategy incorporated the incompatible 2D assembly technique with 3D chiral structures, opening up an intriguing way towards constructing chiral plasmonic structures and modulating of chiroptical effects based on responsive polymeric materials. This article is protected by copyright. All rights reserved.