Study On The Regulation And Mechanism Of Selective Solvents On The Self-assembly Behavior Of Poly(?-benzyl-L-glutamate) Homopolymer And Its Copolymer

As an important part of polymer self-assembly,the self-assembly of polypeptide containing polymers can form a variety of nanostructures,such as spherical micelles,annular micelles,vesicles and so on.However,there are few reports on how to control the morphology and size of self-assembled polypeptide aggregates,so it is important to study the self-assembly of controlled polypeptide homopolymers and polypeptide block copolymers.In this paper,the self-assembly behaviors of poly(?-benzyl-L-glutamate)(PBLG)and poly(?-benzyl-L-glutamate)-b-poly(allyl glycidyl ether)-g-poly(ethylene glycol)(PBLG-b-PAGE-g-PEG)are studied separately,which was mainly divided into two parts:(1)Poly(?-benzyl-L-glutamate)(PBLG)homopolymers with different end-groups were prepare by N-carboxyanhydride(NCA)method.Spindles were prepared by solution self-assembly method,and the length of spindles was controlled by changing the methanol content in the selective solvent.The self-assembly mechanism of PBLG was characterized by FT-IR,CD and LF-NMR.It was found that the hydration layer formed between PBLG and water molecules when PBLG was assembled in pure water,which reduced the hydrophobicity of PBLG and reduced the aggregation of PBLG molecules to form small aggregates.When methanol was present in the selective solvent,the side chain of PBLG extended and the intermolecular distance increased.Moreover,the hydration layer formed by PBLG and water is destroyed,and the hydrophobic interaction of PBLG is enhanced,which makes a large number of PBLG molecules aggregate to form large aggregates.(2)Poly(?-benzyl-L-glutamate)-b-poly(allyl glycidyl ether)-g-poly(ethylene glycol)(PBLG-b-PAGE-g-PEG)were prepare by N-carboxyanhydride(NCA)and anionic ring-opening polymerization method.Spindles with thread on the surface were prepared by solution self-assembly method.By FT-IR,CD and XRD analysis,it was found that PBLG first aggregated into the core of the assembly,while PAGE-g-PEG aggregated to form its shell.Because the PBLG and PAGE are covalently linked and have strong interaction due to hydrophobic interaction after aggregation,the chiral molecule PBLG induces PAGE to be a chiral assembly,which makes the surface of the assembly appear thread like by chiral transfer.