新型光控取向液晶聚合物的合成与表征

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1、南开大学博士学位论文新型光控取向液晶聚合物的合成与表征姓名：吴利平申请学位级别：博士专业：高分子化学与物理指导教师：张保龙20050401与垂直于偏振紫外光的电场方向上的吸光度可知，所制备的取向薄膜具有良好的定向能力，该聚合物是一类具有潜在应用价值的新型液晶光取向薄膜材料。同时，由于侧链型液晶高分子具有分子可设计性和广泛的应用前景。本文以(甲基)丙烯酸酯类含有两个手性中心的侧链液晶高分子的合成为重点，通过改变侧链中柔性间隔基的长度，合成了一系列含有两个手性中心的侧链液晶(甲基)丙烯酸酯类聚合物。采用红外、核磁和GPC表征了各中间体、单体及

2、聚合物的结构和分子量。通过DSC和热台偏光显微镜系统地研究了单体和聚合物的液晶态织构。结果表明，含有六个碳的柔性间隔基的丙烯酸酯类聚合物表现为近晶sA和手性近晶S’c液晶相。关键词光取向，环加成，液晶织构，相转变，手性液晶高分子IIAbstractThecontrolofmolecularalignmentinliquid—crystalphaseatmacroscopicscaleshasbeeninvesfigatedextensiveIybecauseofitsimportanceinopticaloroptoelectrorgca

3、pplications．Itiswellestablishedthatliquidcrystalscanbealignedbymechanicalgroovingofsubstratesurface．Butconventionalrubbingtechniqueinpracticalapplicationhasseveralproblemssuch船dustandstaticchargeduetothemechanicalcontactofrubbingcloth，causingmechanicaldamageofactivedispla

4、ylayer．Moreover，thegeneralmethodtoachievehi学performanceforliquidcrystaldevicerequiressurfaceanchoringconditionsthatcannotbeinducedbyatraditionalmechanicalrubbingmethod．Therefore，thephoto-alignmenttechniqueforLCdisplayhasreceivedmuchattentioninrecentyearsbecauseofitscleana

5、ndphoto—paRernablesystemtowidentheviewingangle．ManykindsofphotoreactivepolymersthatCallundergoanisotropicisomerizationorphotocrosslinkingreactionshavebeenreportedforthephotoalignmentofLC．Nematicliquidcrystalcanbealignedhomogeneouslyonthephotoreactivepolymerfilmifexposedto

6、alinearlypolarizedlight．f15-1glAnisotropic[2+2】cycloadditionofthepolyvinylcinnamatefilmcallinduceirreversiblelowmolecularweightliquidcrystalalignment．119lHowever，mostpolymersinvestigatedrecentlyconminonlythecinnamoylgroupinthesidechainandthethermalstabilityispoor．Inthispa

7、per,wesynthesizedtwonoveloxetanemonomerscontainingbiphenyl，flexiblespacerandcirmamoylgroup．Themonomerswereinitiatedtopolymerizebyborontrifluorideetheraleandledtophotoreactivepolymers，whichishighlysensitivetothelinearlypolarizedlightphotochemically．Thethermalpropertiesandt

8、hemesophasestructureofthepolymerswereinvestigatedbydifferentialscanningcalorimetry(DSC)andtherma