Preparation And Application Of Optically Active Polyacetylene Nanofibers By Electrospinning

Chirality is a basic feature of biological organisms and nature.It is universal and widely exists in nature.Chirality has a great impact on the pharmacological effects of enantiomeric drugs,so it has extremely important significance for the chiral recognition of enantiomeric drugs.In recent years,the research on chiral recognition has made great progress and various chiral recognition methods and chiral separation methods have been established.These methods usually require complex equipment or are expensive.In order to overcome such shortcomings,chiral recognition using fluorescence technology has become a better choice because of its obvious advantages.Fluorescence technology has also made great progress in the detection of enantiomers,with high sensitivity,fast detection speed and high safety.Substances combining fluorescence technology with the chiral recognition ability of chiral helical polymers that possess chiral amplification can provide more promising materials.At present,the most common methods for the preparation of chiral nanofibers are self-assembly,non-covalent bonding,and mesoporous induction.These methods have complicated preparation conditions and complicated procedures.Compared with these methods,the method of preparing nanofibers by electrospinning technology has obvious advantages.Especially in the preparation of polyacetylene nanofibers,the electrospinning method has unique advantages.Due to the limited variety of chiral substances and the high cost.The use of natural biomass materials as chiral induction agents to induce optical activity of achiral polyacetylene is of great significance for simplifying the preparation of chiral nanofibers and reducing costs.The main contents in this thesis are as follows:Firstly,the nanofiber membrane was prepared by electrospinning from the prepared monosubstituted polyacetylene with pendent fluorescent group.According to the scanning electron microscope characterization results,the nanofiber diameter was about 100 nm.The chiral fluorescent nanofiber membrane was confirmed to have chiral and fluorescent characteristics through circular dichroism and fluorescence spectra measurement.One of the prepared enantiomeric fluorescent nanofiber membranes exhibited enantioselective recognition ability toward chiral amino acid enantiomers(represented by alanine enantiomers)and chiral amine enantiomers(with phenethylamine enantiomers as model)through chiral fluorescence recognition.Based on the results,a chiral fluorescence recognition mechanism of chiral fluorescent nanofiber membrane was proposed.Then,we added cellulose nanocrystals as an inducer to achiral polyacetylene for electrospinning.The research on the two-component(cellulose nanocrystals,polyacrylonitrile)and three-component additions(achiral polyacetylene,cellulose nanocrystals,polyacrylonitrile)found that 1%of cellulose nanocrystals and 5%of polyacetylene were the optimal preparation conditions.Through the study of three achiral substituted polyacetylenes with different side groups,it was found that for achiral polyacetylenes with appropriate side groups forming hydrogen bonds between the side groups,that can be induced by cellulose nanocrystals to take one-handed predominantly helical polyacetylene.The acetylenic nanofiber membrane has circularly polarized light emitting properties.