Preparation And Properties Of Helical Polyisocyanide Gels

Electrolytes are an important part of electrochemical energy storage devices.Traditional solid and liquid electrolytes have certain defects.Therefore,gel electrolytes with high safety,good stability and excellent processability have become alternative research hotspots.In this paper,based on the polyisocyanide backbone modified with peptide bonds,two helical polyisocyanide molecules modified with alkyl chains,namely the polyisonitro-D-alanine-L-alanine octyl,dodecyl ester(C8-7,C12-7)and an alkoxy chain modified helical polyisoprene molecule,namely the D-alanine-L-alanine triacetal ester(EG-7),have been synthesized.Through nuclear magnetic resonance hydrogen spectroscopy,Fourier infrared spectroscopy,ultraviolet-visible spectroscopy,circular dichroism,atomic force microscopy,scanning electron microscopy,the structures of the three helical polymers and some of the important intermediate products have been characterized and their properties were measured.Gelation tests showed that these three polymers had better gelation performance for aromatic solvents.Among them,C8-7 and C12-7 could gelate less organic solvents than EG-7.The rheology experiments revealed that the shorter side alkyl chain resulting in stronger gelation ability.In addition,C8-7 and C12-7 had better thixotropy,while EG-7 had poor thixotropy in organic solvents.As observed by atomic force microscope and scanning electron microscope,these gel materials have a three-dimensional network structure.The possible formation mechanism of the gel was studied by Fourier infrared spectroscopy,and the results showed that the hydrogen bond and the van der Waals interaction between the alkyl chains were the main driving forces for the formation of the gels.In view of the fact that the helical polyisocyanide molecule EG-7 modified by alkoxy chain is a good hydrogel factor,and its gel materials have good biocompatibility in biomedical fields such as wound dressings,tissue engineering scaffolds,etc.This paper explored the application of EG-7 hydrogel in aqueous electrolytes.It was found that there were two states(gel and solution)in aqueous electrolytes of EG-7,both of which showed temperature-sensitive properties in water,and demonstrated certain conductivity.The research on the gel properties,structures,rheological properties and gel mechanism of three helix-based polyisonitrile polymer gel factors,as well as the application exploration of EG-7 hydrogel in aqueous electrolytes,shed light for the further development of functionalized gel materials.