Synthesis And Characterization Of Azo Liquid Crystal Polymers Containing Cholesteryl Groups

Azo phenyl groups is a kind of optical activity,therefore azo liquid crystal polymer,as a kind of data storage materials and optical functional materials,has been widespread concern.Chiral azo liquid crystal polymer has LCD sex not only,but also has many unique optical properties,its synthesis and optical response has been received extensive attention of scholars both at home and abroad.In this paper,one kind of azo liquid crystal monomer L and two kinds of cholesteryl liquid crystal monomer M1,M2 and two kinds of single phenol monomers N1,N2 are synthesized.At the same time,three series of side chain polysiloxane liquid crystal polymers,the cholesteric series of P1,P2 and P3,and three series of azo liquid crystal polymers P1A,P2A and P3A are synthesized.The POM,FT-IR,UV-Vis,DSC,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 P1A,P2A and P3A contrast to its precursor polymer P1,P2 and P3 series,UV graph shows P1A,P2A and P3A occur with azo absorption peak and peak at 350nm and 455nm.The azo absorption peak increased progressively while the L increased.In the light,the polymer occurs cis-trans isomerization,stop light,the light will return to the state before.It shows three series of azo polymer having photochromic properties.By DSC curve,all the heating curve and cooling curve of M1,M2 and L appeare corresponding and obvious glass transition temperature and melting point.The heating curves of precursor polymer P1,P2 and P3 series appeare obvious glass transition temperature and melting point,but do not appear obvious clearing point,showing that P1,P2 and P3 series belong to semicrystalline polymers.As the change of composition,the TG of P1 reduce after rising first,the TI reduced gradually;the Tg of P2 reduce gradually,the TI also reduced gradually;the Tg of P3 rise after lower first,the TI is gradually reduced.As the change of composition,the Tg of P1A reduce gradually,the TI also reduced gradually;the Tg of P2A reduce after rising first,the Ti reduced gradually;the Tg of P3A reduce after rising first then reduce again,the Ti is gradually reduced.Measured by POM,all the three liquid crystal monomers have obvious texture features.L is nematic liquid crystal monomer,while M1 and M2 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 P1,P2 and P3 series,the more the content of M,the more obvious the texture is,and they even appear oily streak texture,indicating that the three series belong to cholesteric liquid crystal.The azo liquid crystal polymer P1a,P2A and P3A series can see obvious and bright color texture.With the increase of the content of L,the colour diversity of polymers recedes,and red gradually dominates,showing that the three series belong to cholesteric liquid crystal.By rotation,precursor polymer P1,P2 and P3 series and azo liquid crystal polymer P1A,P2A and P3A series are left-handed optical active substances,because both polymer with sinistral optical activity of cholesteric monomer for chiral center,and as the chiral monomer content gradually reduce,polymer polarimetric decreases.