Preparation And Properties Of Optically Active Micro/nano-particles Constructed From Helical Substituted Polyacetylenes

Chiral micro/nano-structures play an indispensable role in the operation of nature.Inspired by nature,a large number of chiral materials have been continuously designed and developed,which has promoted the vigorous development of chiral-related fields.In particular,chiral micro/nano-particles have aroused significant attention thanks to their high specific surface area,controllable size and surface morphology,strong dispersion ability as well as good processing performance.On the other hand,optically active helical substituted polyacetylenes,as a prominent member of the chiral polymer family,have shown promising applications in fields such as enantioseparation,photoelectronic devices,sensing and biomedicine.Accordingly,the construction of chiral micro/nano-particles using chiral helical polyacetylenes is of great significance for the development of more kinds of advanced chiral materials.In this thesis,two types of optically active micro/nano-particles were constructed based on chiral helical polyacetylenes:chiral non-spherical particles and chiral fluorescent hybrid nanoparticles.The specific research contents are as follows.1.Optically active non-spherical particles with controllable morphologies were constructed by template surface modification method.In more detail,the monodispersed poly（glycidyl methacrylate）（PGMA）particles were employed as seeds to prepare non-spherical template particles with jar-like,golf ball-like and raspberry-like morphology by swelling and phase separation,as well as seed emulsion polymerization.Optically active non-spherical particles were prepared by acetylation of template particles and further copolymerization with chiral alkyne monomer.The morphology and structure of the particles were characterized by FT-IR,SEM,elemental analysis and XPS.CD and UV-vis spectra show that the polyacetylenes on the surface of the prepared chiral non-spherical particles have helical chirality.2.The SiO₂nanoparticles were first prepared by sol-gel method.Then,the as-obtained SiO₂particles were modified with alkynyl groups.The resulting products were further copolymerized with chiral alkyne monomer and achiral fluorescent alkyne monomer,and the chiral fluorescent copolymers were successfully grafted on the surface of the particles,in which the side group of polymer backbone bears tetraphenylethylene moieties with AIE property.The structure and morphology of the relevant particles were analyzed by means of FT-IR,SEM,and elemental analysis.The results of CD and UV-vis spectra confirmed that the polyacetylenes on the surface of the chiral hybrid particles possess excess one-handed helical structure.The fluorescence spectra show that the chiral hybrid particles possess aggregation-induced emission（AIE）properties.