The colloid and interface group of Yangzhou University has made important progress in the construction of polyaniline supramolecular chirality

As one of the basic properties of nature, chirality can be reflected in different levels: from the chiral carbon atom of small molecule to the asymmetric conformation of large molecule, then to the chiral nanostructure of supramolecular assembly At the supramolecular level, complex chiral biomolecules (such as double helix DNA and α - helix protein) play a key role in the physiological process of living organisms Inspired by these biological structures, in recent years, a variety of chiral structural functional materials with good electrical, optical or magnetic properties have been designed and constructed As one of the most in-depth functional synthetic materials, PANI with chiral nanostructures has potential applications in the fields of chiral catalysis, chiral sensing, enantioselective separation and chiral electronic devices PANI chiral nanostructures were prepared by chemical oxidation of aniline monomer in acidic aqueous solution with ammonium persulfate as oxidant under the guidance of chiral acid or helix protein template At present, most of the artificial chiral nanostructures are helical nanobelts or nanofibers Compared with these simple chiral nanostructures, the complex chiral nanostructures (such as hollow helix) have the desired biomimetic function, so they have attracted more attention However, the preparation of functional materials with complex chiral nanostructures is still a major scientific challenge In addition, the construction of chiral nanostructures from achiral molecules not only involves the important scientific problems of the origin of chirality in nature, but also helps to create multi-functional chiral materials for achiral functional molecules In the early stage, the research group of colloid and interface of Yangzhou University prepared the chiral helix nanoribbons of aniline through the chemical oxidation of aniline in the mixed solvent of non chiral isopropanol / water The single chiral nanoribbons can be obtained by adjusting the alcohol content in the mixed solvent The chiral helix nanobelts of monochiral Oligoaniline can be used for the chiral separation of amino acid enantiomers, and the separation effect of phenylalanine enantiomers is better (j.am.chem.soc., 2018, 140, 9417-9425) In order to further improve the molecular weight of conjugated molecules and optimize the chiral nanostructures, recently, our group introduced low concentration inorganic acids into the reaction system, and constructed polyaniline hollow nanospheres with complex chiral nanostructures through the chemical oxidation of aniline in the Nonchiral mixture of HCl / isopropanol / water Based on the experimental results, the possible formation mechanism of hollow nanohelix was proposed by the research team: Taking the Oligoaniline nanohelix produced in the early stage of the reaction as the template, the polyaniline hollow nanohelix was gradually realized through the process of Oligoaniline chain growing into polymer in the solution, polymer adsorbing on the surface of the nanobelt to form shell, and oligomer re dissolving of the nanobelt It is found that the formation of Polyaniline and the construction of hollow structure are ensured by the appropriate concentration of inorganic acid, which leads to the large specific surface area and good environmental stability of polyaniline hollow nanoribbons Compared with the polyaniline nanoribbons, polyaniline nanohelix has better enantioselectivity for a variety of amino acids The results were published in ACS Nano (DOI: 10.1021 / acsnano 8b09784) Professor Guo Rong and Professor Han Jie from the school of chemistry and chemical engineering of Yangzhou University are the co authors of this paper Zhou Chuanqiang, associate researcher of the test center of Yangzhou University, is the first author of this paper Ren Yuanyuan and Xu Qianqian, graduate students, participated in relevant experiments This research has been supported by the National Natural Science Foundation of China and Jiangsu University's advantageous discipline construction project.