Chiral Confined Unimolecular Micelles for Controlled In Situ Fabrication of Optically Active Hybrid Nanostructures

Abstract

Functional nanomaterials made by chiral induction have attracted extensive attention because of their intriguing characteristics and potential applications. However, the precise and controllable fabrication of chiral nanomaterials still remains challenging but is highly desired. In this study, chiral unimolecular micelles with different molecular weights and chiroptical activities were prepared by photoinduced atom transfer radical polymerization (photoATRP). Through nanoconfined growth, the chiral plasmonic nanoparticle assemblies with predesigned size and morphology were prepared using chiral unimolecular micelles as nanoreactors. The controllability over chiral assemblies and the size effect on chiroptical properties were also investigated. Furthermore, chiral complexes with absorption asymmetry and circularly polarized luminescence (g lum = 4.25 × 10–4) were easily constructed via mixing of organic fluorescent molecules and chiral templates based on intermolecular hydrogen bonds. Such results indicated that our unimolecular-micelle-based templates enable the controllable preparation of both inorganic and organic chiral nanostructures with tailored dimensions, sizes, compositions, and optical activities.

Precise Construction of Chiral Plasmonic Nanoparticles for Enantioselective Discrimination

“…Compared with linear block copolymers, unimolecular micelles usually exhibit the higher structural stability. , Through living polymerization, unimolecular-micelle-based templates allowed for the preparation of nearly monodisperse nanocrystals with precisely controlled dimensions, compositions, and architectures . For example, chiral ultrasmall Au nanoparticle assemblies could be obtained with target size . But the chiroptical activities and LSPR effect were relatively weak, which hinders the further application of enantioselective discrimination.…”

“…38 For example, chiral ultrasmall Au nanoparticle assemblies could be obtained with target size. 32 But the chiroptical activities and LSPR effect were relatively weak, which hinders the further application of enantioselective discrimination.…”

“…At present, the preparation of chiral plasmonic nanomaterials could be roughly divided into two categories, as top-down (direct laser writing, e-beam lithography, glancing-angle deposition) and bottom-up methods . Soft templates (polymers, peptides, and DNA) as one of the popular bottom-up methodologies have displayed significant advantages of the mature polymerization techniques and diverse monomers, which allows for the hierarchical regulation on components and optical properties. Kim utilized linear polystyrene- block -poly­(4-vinylpyridine) as templates with chiral additives, to synthesize chiral Au, Ag, and metal oxide nanoparticles through in situ growth within the corresponding micelles .…”