Preparation Of One-dimensional Photonic Crystal And Regulation The Properties Of Magnetic Polymer By Self-assembly Of Block Polymer

In this paper,two dendronized monomers with different refractive index were designed and synthesized.Series of dendronized block copolymers were synthesized by ring-opening metathesis polymerization?ROMP?.One dimensional photonic crystals?1D PhCs?based on self-assembled dendronized block copolymers were obtained with high reflection wavelength and narrow bandwidth.The steric hindrance of the dendronized side groups increased the rigidity of main chains and thus lowered the chain entanglement and energetic barrier during the self-assembly.The whole spectrum 1D PhCs with high reflectance were prepared by thin film self-assembly of the dendronized block copolymers with different polymerization degree.The presence of layered structures was demonstrated by scanning electron microscopy?SEM?,and small-angle and ultra-small X-ray diffraction?SAXS and USAXS?.The self-assembly domain of the lamellar phases were increased from 50 nm to 500 nm with the main chain DP increased from 400 to 1300.And,the linear relationship between maximum reflectance wavelength and the main chain DP were founded.The rapid and simple preparation of 1D PhCs with tunable reflectance wavelength showed great potential in application.At the same time,a series of brush block copolymers with different molecular weights were synthesized in this paper.The effects of thermal annealing on the properties of photonic crystals were investigated.After thermal self-assembly,the maximum reflection wavelength was obviously red shifted,and the reflectivity decreased to a certain degree.The linear relationship between the degree of polymerization of main chain and the main reflection wavelength was obtained.We can predict the performance of the material via designing the structure.The tadpole-shaped magnetic block copolymer?POSS-PSt-b-QP4VP?FeCl₄??was reported in this work.The prepared block copolymer was paramagnetic and the magnetic susceptibility of the block copolymer was almost doubled after self-assembly in thin film.Since the composition of the block copolymer is unchanged,the increase of the susceptibility should be generated by the self-assembly,which makes the magnetic FeCl₄^-more ordered.And,self-assembly will be an efficient and convenient method in improving magnetic properties of such polymers.