Preparation And Aggregation Structures Of Perylene Diimide Derivatives Based On Ionic Self-assembly

Perylene diimide(PDI)derivatives are a class of polycyclic aromatic compounds,with excellent optical and electrical properties and thermal stability,having significant applications in the field of fluorescent sensing materials,solar cells,organic field effect transistor,and so on.Ion self-assembly is a novel method for preparing supramolecular materials.The building blocks with opposite charge are coupled together through electrostatic interaction,and further assembled into supramolecule with specific structure and function.There are several advantages to synthesize PDI derivatives using ion selfassembly method: the simplicity of synthesis and short reaction time,and it is of great scientific significance to construct the ordered structure of the molecule.In this paper,firstly,PDI and PDIC with carboxyl functional groups were synthesized,and then selected as building blocks with two cationic surfactants(DHAB and DOAB)to synthesize three new types of perylene diimide derivatives by an ion self-assembly method.1H NMR and FT IR were used to determine the composition and structure of these five products.We studied UV-Vis spectra and fluorescence spectra of these three derivatives in solution under the same conditions,and found the shape and wavelength spectrum are basically the same,because their electronic structures are nearly the same.By studying the self-assembly behavior PDIC-DOAB in the composite solvent,it was found that increasing the proportion of the poor solvent will drive PDIC-DOAB molecular to selfassemble into H-aggregates.The thermal stability of these three derivatives were tested by thermal gravimetric method.DSC,1D SAXS,1D WAXD and 2D WAXD were also used to characterize their phase behaviors and aggregation structures.We found that these three complexes showed different phase behaviors and self-assembly behaviors: PDIC-DOAB presented three different aggregation structures at different temperatures: it was monoclinic structure at room temperature,when elevated temperature,it turned to hexagonal columnar phase,when continued to heat up,a new monoclinic structure was formed;for PDI-DHAB and PDI-DOAB,a lamellar structure was formed with high temperature.By PLM we found these three oriented PDI derivatives exhibited anisotropic properties,which indicated that they have potential applications in polarization optical devices.