非偏振光诱导含聚二甲基硅氧烷的偶氮苯液晶嵌段共聚物薄膜微相分离结构的垂直取向  

Perpendicular Orientation of Polydimethylsiloxane Nanocylinders in Thin Film of a Liquid Crystalline Block Copolymer Induced by Unpolarized Light

作　　者：李玉洁 罗龙飞 沈志豪[2] 范星河[2] 郑世军[1] Yu-jie Li;Long-fei Luo;Zhi-hao Shen;Xing-he Fan;Shi-jun Zheng(School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450001;Beijing National Research Center for Molecular Sciences,Key Laboratory of Polymer Chemistry and Physics Education Ministry,Center for Soft Matter Science and Engineering of Peking University,Institute of Chemistry and Molecular Science,Peking University,Beijing 100871)

机构地区：[1]郑州大学材料科学与工程学院,郑州450001 [2]北京分子科学国家研究中心,高分子化学与物理教育部重点实验室,北京大学软物质科学与工程中心,北京大学化学与分子工程学院,北京100871

出　　处：《高分子学报》2021年第12期1611-1621,I0004,共12页Acta Polymerica Sinica

基　　金：国家重点研发计划(项目号2018YFB0703702);国家自然科学基金(基金号51725301,51921002)资助项目.

摘　　要：通过原子转移自由基聚合(ATRP)合成了聚二甲基硅氧烷-嵌段-聚(11-(4-(4'-氰基偶氮苯)苯氧基)十一烷基丙烯酸酯)(PDMS-b-PAz)的二嵌段共聚物,其中PDMS的体积分数是27%.利用原子力显微镜和掠入射小角X射线散射等表征手段研究了不同厚度的薄膜分别在热退火和非偏振光取向后的组装形貌.结果显示:热退火时,当膜厚较低时,形成的是面内无序排列的柱状结构;而当膜厚增加到319 nm时,形成的是面内排列与垂直于基底排列共存的杂化结构,即使当膜厚增加至406 nm时,这种杂化结构仍然保持.而采用非偏振光取向时,即使对于厚度仅为55 nm的薄膜就能获得垂直于基底排列的微相分离结构,且当膜厚增加至406 nm时,这种结构仍然得到保持.这是首次利用非偏振光诱导含PDMS的嵌段共聚物薄膜取向得到PDMS纳米柱垂直于基底的排列,这一取向方法将有助于推动含PDMS的嵌段共聚物薄膜在纳米模板等领域中的应用.A diblock copolymer containing polydimethylsiloxane and an azobenzene-based liquid crystalline polymer,PDMS-b-PAz,was synthesized by atom transfer radical polymerization(ATRP).The volume fraction of PDMS was 27%.Atomic force microscopy(AFM)and grazing-incidence small-angle X-ray scattering(GI-SAXS)were used to investigate the morphologies of thin films with different thicknesses after thermal annealing and unpolarized light orientation.The results show that the disordered cylindrical structure is formed in thinner films during thermal annealing.However,when the film thickness is increased to 319 nm,a coexistence of in plane and out-of-plane arranged PDMS nanocylinders were observed.Even when the film thickness is increased to 406 nm,this coexistent state still remains.The microphase-separated structure perpendicular to the substrate can be obtained even for the thin film with a thickness of only 55 nm when being aligned with unpolarized light,and this structure is maintained when the film thickness is increased to 406 nm.This is the first time that the perpendicular orientation of PDMS nanocylinders in block copolymer films is obtained by the alignment of unpolarized light.This orientation method will benefit the application of PDMS-containing block copolymer films in nanotemplates and other fields.

关 键 词：嵌段共聚物 偶氮苯液晶高分子 聚二甲基硅氧烷 非偏振光取向 

分 类 号：TQ317[化学工程—高聚物工业] TB383.2[一般工业技术—材料科学与工程]