Design And Self-assembly Of Amphiphilic Dendrimers Based On Glutamate

Soft nanomaterials with circularly polarized luminescence(CPL)have been currently attracting great interest.Here,we reported a pyrene-containing π-peptide dendrons hydrogel,which showed 1D and 2D nanostructures with varied CPL activities.It was found that the individual dendron formed hydrogels in a wide pH range(3-12)and self-assembled into helices with pH-tuned pitches.Through the chirality transfer,the pyrene unit could show CPL originated from both the monomer and excimer bands.When cyclodextrin was introduced,different supra-dendrons were obtained with β-cyclodextrin(PGAc@β-CD)and y-cyclodextrin(PGAc@y-CD)through host-guest interactions,respectively.Interestingly,the PGAc@β-CD and PGAc@y-CD supra-dendrons self-assembled into 2D nanosheet and entangled nanofibers,respectively,showing cyclodextrin induced circularly polarized emission from both the monomer and excimer bands of pyrene moiety.Thus,through a simple host-guest interaction,both the nanostructures and the chiroptical activities could be modulated.Moreover,it could be used as acceptor for visible-to-UV photon upconversion based on triplet-triplet annihilation(TTA-UC).Through host-guest interaction with β-CD,stable photon upconverted emission could be obtained under aerated conditions.In all,this work presented a luminescent gel system with photon upconversion property and wide pH adaptability and chiral adjustment.