Synthesis And Characterization Of Chiral Azo Polysiloxane Polymers

Chiral liquid crystal polymer is one of the hot spots in research,the introduction of chiral molecules into liquid crystal polymers will have a significant effect on the properties of liquid crystal polymers.Azo phenyl groups is a kind of optical activity,therefore,the liquid crystal polymers which containing azobenzene groups have great value in information storage materials and optical functional materials.Polysiloxane liquid crystal has a unique optical,electromagnetism,viscosity-temperature characteristics and good mechanical properties,and thus it has a wide application in the future.Chiral azo polysiloxane liquid crystal polymer has LCD property not only,but also has many unique optical properties,its synthesis and characterization has been received extensive attention of scholars both at home and abroad.In this paper,one kind of azo liquid crystal monomer M3 and two kinds of cholesteryl liquid crystal monomer M1,K1 and two kinds of single phenol monomers M2,K2 are synthesized.At the same time,three series of side chain polysiloxane liquid crystal polymers,the cholesteric series of QP1,QP2 and QP3,and three series of azo liquid crystal polymers ZP1,ZP2 and ZP3 are synthesized.The POM,FT-IR,UV-Vis,DSC,XRD,Rotation were used to characterize the structure of the five monomers and six series,showing that the structures are in line with the molecular design.Known by the UV-Vis,azo polymer ZP1,ZP2 and ZP3 contrast to its precursor polymer QP1,QP2 and QP3 series,UV graph shows ZP1,ZP2 and ZP3 occur with azo absorption peak and peak at 350 nm and 455 nm.The azo absorption peak increased progressively while the M3 increased.In the light,the polymer occurs cis-trans isomerization,stop light,the azo polymer will return to the state before light.It shows three series of azo polymer having photochromic properties.By DSC curve,all the heating curve and cooling curve of M1,K1 and M3 appeare corresponding and obvious glass transition temperature and melting point.The heating curves of precursor polymer QP1,QP2,QP3 and azo liquid crystal polymers ZP1,ZP2,ZP3 series appeare obvious glass transition temperature.As the change of composition,the Tg of QP1 rising gradually,the T1 reduced gradually;the Tg of QP2 rising gradually,the T1 also reduced gradually;the Tg of QP3 lower first and then rise and then reduced again,the T1 is rise after lower first.As the change of composition,the Tg of ZP1 rise after lower first,the T1 also rise after lower first;the Tg of ZP2 reduce after rising first,the T1 rise after lower first;the Tg of ZP3 lower first and then rise and then reduced again,the Ti is gradually reduced.Measured by POM,all the three liquid crystal monomers have obvious texture features.M1,K1 and M3 are cholesteric liquid crystal monomers.The six series,in addition to the self-assembled products,have wide temperature range of liquid crystal phase,whose liquid crystalline property are manifested on the special color texture,indicating that all the polymers are thermotropic and enantiotropic liquid crystalline polymers both in the process of heating and cooling.To the precursor polymer QP1,QP2 and QP3 series,the more content of M1 and K1,the more obvious the texture is,and they appear oily streak texture,indicating that the three series belong to cholesteric liquid crystal.The azo liquid crystal polymer ZP1,ZP2 and ZP3 series can see obvious and bright color texture.With the increase of the content of M3,the colour diversity of polymers recedes,and red gradually dominates,showing that the three series belong to cholesteric liquid crystal.By rotation,precursor polymer QP1,QP2 and QP3 series and azo liquid crystal polymer ZP1,ZP2 and ZP3 series are left-handed optical active substances.because precursor polymer with sinistral optical activity of cholesteric monomer for chiral center,and as the chiral monomer content gradually reduce,polymer polarimetric decreases.However,The rotation luminosity of azo liquid crystal polymer increased with the increase of the content of azo monoic acid M3.Measured by XRD,Further verified that precursor polymer QP1,QP2,QP3 and azo liquid crystal polymers ZP1,ZP2,ZP3 are belong to cholesteric liquid crystal.