手性多孔嵌段共聚物薄膜诱导手性金纳米粒子的手性组装

Chiral Assembly of Chiral Gold Nanoparticles Induced by Chiral Porous Block Copolymer Film

以手性酒石酸(TA)分子诱导嵌段共聚物聚丁二烯-b-聚环氧乙烷(PBd-b-PEO)手性组装,通过除去TA分子形成手性多孔薄膜,并作为模板诱导手性金纳米粒子(Au NPs)手性组装。利用透射电子显微镜(TEM)和圆二色光谱(CD)表征了手性PBd-b-PEO/Au NPs复合薄膜的组装特性。结果表明:当手性Au NPs与孔道结构的手性一致时,更有利于手性Au NPs手性信号的表达。当手性Au NPs沉积量比较少时,复合薄膜只表现出手性Au NPs的手性排列信号;而当Au NPs沉积量大时,复合薄膜表现出手性Au NPs本身和组装体的共同手性信号。

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.