The Study Of Supramolecular Helical Self-Assembly Structures And Control Based On Reprecipitation

Chirality is one of the key factors in nature.As a typical example of chiral structures,helix performs a series of complex functions in life,such as proteins and DNA.Besides,supramolecular chiral nanostructures play potential applications in optoelectronic materials and biomedical science.In recent years,the study of supramolecular chiral self-assembly attracted broad attention.Molecular packing modes play an important role in self-assembly,and provide potential guidance in the application of nanostructures.One of the most challengeable problems is how to control the packing modes of supramolecule helices,and how to realize the tunable control of supramolecule helical nanostructures is also a great challenge in present research.The self-assembly process of four C₃-symmetric molecules were studied in H₂O and cetyltrimethylammonium bromide（CTAB）aqueous solution via reprecipitation.Then we investigated the effect of the change of self-assembly environment and molecular structures on supramolecular helical packing modes and self-assembly structure.The main contents are as follows:1.The self-assembly of a C₃-symmetric molecule BTECM in H₂O and CTAB aqueous solution upon aging for different times with the reprecipitation method was studied.The result showed that the supramolecular helical self-assembly of BTECM occurred in H₂O and CTAB aqueous solution,furthermore,the self-assembly environments played an important role in the packing modes of helical nanostructures.In H₂O,BTECM molecules aggregate via H-type mode and it is inclined to aggregate by J-type mode in CTAB aqueous solution.This investigation provides a solid example that helical nanostructures could be prepared from achiral C₃-symmetric molecules by reprecipitation.Especially,the aggregate modes of helical nanostructures were regulated by tuning the self-assembly environment.2.The self-assembly process of four C₃-symmetric molecules（BTECM,BTECE,BTECP and BTECB）were studied in H₂O and CTAB aqueous solution via reprecipitation.On the edges of these molecules,different alkyl groups were introduced.The results of spectroscopical and morphological characterization proved that self-assembly environments and different alkyl groups on the edge of these molecules effect the self-assembly of these molecules.Especially,the self-assembly of C₃-symmetric molecules were regulated by tuning the length of alkyl groups on the edge of these molecules.