Assembly And Characterization Of Poly(Ethyleneglycol)-b-Poly(N-(2-Phenylethyl) Glycine) Diblock Copolymer

Polypeptoids are synthetic biomacromolecules with similar main chain structure to the polypeptides.The side chain substituents are on the nitrogen atom of the amide bond instead of the carbon atom,leading to a disappearance of hydrogen bond donor and chiral center,which thus weakens the interaction between the main chain.So it can be well dissolved in many solvents.Polypeptoid has good biocompatibility and excellent degradability with biological cells and tissues.The physicochemical properties of clustered peptides largely depend on the types of side chains of the clustered peptides,and their physicochemical properties can be changed by adjusting the side chains.When the side chains of the amphiphilic clustering peptide block copolymers are crystallizable alkyl chains,the block copolymers can form assemblies of various structures through crystallization-driven self-assembly(CDSA)in selective solvents.In order to break through the size limitation of assembled structures and make further progress in biomolecular membranes,amphiphilic block copolymers can be used to synthesize large-sized membrane structures at the interface.In this paper,the assembly behavior of the amphiphilic block copolymer polyethylene glycol-poly(N-(2-phenethyl)glycine)(PEG-b-PNPE)in solution and at the air-water interface was studied to prepare the Large-scale two-dimensional membrane structures.1.CDSA offers an effective strategy for delicate control of the nanostructures of block copolymers.Herein,we report the solubility effect on the self-assembly of a PEG-b-PNPE block copolymer with a crystalline core-forming polypeptoid in aqueous solution.The influences of temperature,sonication and the corona-chain length that governs the solubility were systematically investigated.We demonstrate that the balance between the crystallization and solubility of the polymer dominates the nanostructures.When the crystallization of the PNPE block is restricted,1D nanofibers are exclusively present.Otherwise,a majority of 2D nanosheets induced by CDSA are observed.Additionally,the ?–? interaction also plays a crucial role in the assembly process.A phase diagram of PEG-b-PNPE assemblies at various DPs of PEG and PNPE is further shown.The capability to assemble the polymers into nanostructures with different dimensions through a facile assembly process offers a convenient platform to access a wide range of new materials for many applications.2.The amphiphilic block copolymer PEG-b-PNPE can self-assembly into a large-scale monolayer two-dimensional nanofilm structure at the air-water interface.We systematically explored the effects of polymerization degree,time and volatilization rate on self-assembly.The results show that the hydrophobic segment with higher degree of polymerization and the lower volatilization rate contribute to the formation of two-dimensional membrane structures.At the same time,the PNPE molecular chain takes a more favorable conformation arrangement,and the ?-? interaction on the phenyl group plays a crucial role in the formation of the two-dimensional membrane structure.We extruded the monolayer using the Langmuir-Blodgett(LB)technique and were able to obtain a more stable bilayer structure.At the same time,Janus membrane materials were prepared at the air-water interface using PEG-b-PNPE samples with a higher degree of polymerization,which enriched the research and development of PEG-b-PNPE systems.