Synthesis And Self-assembly Of Dendronized And Bottlebrush Block Copolymers

Self-assembly of block copolymers plays an increasingly important role in the study of functional polymer materials,especially in biomedical materials,microelectronic materials,photoelectric materials,catalysts and other fields.However,the linear block copolymer has relatively serious chain entanglement,which makes it difficult to form large-sized(? 100 nm)nanostructured materials by self-assembly.In this paper,two kinds of nonlinear dendronized and bottlebrush block copolymers were synthesized,and photonic crystal materials with large structural domains were prepared by thin-film self-assembly and thermo-compression self-assembly of block copolymers.Firstly,two norbornenyl functionalized wedged monomers were synthesized,and the aggregation-induced emission group was introduced into one of the monomers.Dendronized block copolymer with main chain polymerization degree of 400:400 was prepared by ring-opening metathesis polymerization.The dendronized block copolymer was used for thin-film self-assembly to prepare one-dimensional photonic crystal materials with reflected wavelength of 443 nm and periodic domain spacing of133 nm.Because of the presence of AIE groups,photonic crystal films showed two different colors under natural light and ultraviolet light.In addition,the obtained dendronized block copolymer was self-assembled into core-shell nanoparticles in selective solvent,and the diameter of which was calculated to be 107 nm by transmission electron microscope.The solution showed blue color with reflected wavelength of 416 nm.Then,four norbornenyl functionalized macromonomers were synthesized,and the bottlebrush block copolymers with hard and soft main chain structures and polymerization degree of 100:100 were prepared by ring-opening metathesis polymerization.Both of the bottlebrush block copolymers could be self-assembled under thermo-compression.One-dimensional photonic crystal films with reflected wavelength of 370 nm/334 nm and periodic domain spacing of 101 nm/90 nm were obtained respectively.The thermo-compression self-assembly method of the bottlebrush block copolymer was benefited from rapid self-assembly and free of solvent,which shows great potential applications in the pressure detection at high temperature.