Abstract:
In the past decades, chiral assembly of metal nanoparticles received intensive interest due to its great potential in designing functional materials, especially the preparation of metamaterials. In this work, the assembly of chiral gold nanoparticles (Au NPs) in chiral porous block copolymer film was investigated. Helical structures with controlled handedness were firstly prepared by using diblock copolymer, poly(1, 4-butadien)-
b-poly(ethylene oxide) (PBd-
b-PEO), and enantiopure tartaric acid (TA) molecules through additive-driven self-assembly approach. Porous PBd-
b-PEO film was then prepared by immersing the PBd-
b-PEO/TA hybrid film into LiBr aqueous solution, which was characterized by using TEM and FT-IR. CD spectra proved that the porous PBd-
b-PEO film still presented weak chirality even after the removal of TA molecules. Au NPs capped with
L-glutathione molecule were backfilled into the porous PBd-
b-PEO film and the chiral optical property of the obtained PBd-
b-PEO/Au NPs hybrid film was investigated by CD spectra. Experimental results indicated that the chiral optical properties of the PBd-
b-PEO/Au NPs hybrid film were affected not only by the chirality relationship between Au NPs and PBd-
b-PEO film, but also by the deposition amounts of Au NPs in the porous film. When Au NPs showed the same chirality with the porous PBd-
b-PEO film, the PBd-
b-PEO/Au NPs hybrid film showed chiral optical response of both Au NPs and their assemblies. When the chirality of Au NPs and porous PBd-
b-PEO film was different, only chiral optical response of Au NPs assemblies presented. For the effect of the Au NPs deposition, only chirality of NPs assemblies presented when less nanoparticles deposited into the porous film. However, the chirality of
L-glutathione capped Au NPs itself appeared for large amount deposition of Au NPs in the porous film.