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Liquid crystallinity and thermal properties of polyhedral oligomeric silsesquioxane/side-chain azobenzene hybrid copolymer
Nanotechnology Reviews ( IF 7.4 ) Pub Date : 2020-09-11 , DOI: 10.1515/ntrev-2020-0068
Xiaotao Wang 1 , Zhuofan Chen 1 , Yiwan Huang 1 , Xiaotie Ye 2 , Jiacheng Wang 1 , Yuye Yang 1 , Xuefeng Li 1 , Zuifang Liu 1
Affiliation  

Abstract Acrylic acid-modified polyhedral oligomeric silsesquioxane (AC-POSS) was synthesized by the reaction between the amine groups in polyhedral oligomeric silsesquioxane (POSS) and acrylic acid, which could dissolve in water and can be easily purified. Free-radical copolymerization was applied to synthesize azobenzene liquid crystalline polymer silsesquioxane (LCP-POSS) with different proportions of AC-POSS and liquid crystalline monomers. The trans-isomers of azobenzene moieties in LCP-POSS were gradually transformed to cis-isomers with increasing ultraviolet irradiation time. The photoisomerization reaction of liquid crystalline polymer (LCP) and LCP-POSS showed the first-order dynamic reaction. Compared with the LCP, the photoisomerization rate constant of LCP-POSS was decreased due to the space steric hindrance of the POSS as a rigid segment. The phase transition temperature of liquid crystalline in LCP-POSS increased with increasing POSS content, and the liquid crystalline texture in LCP-POSS became smaller under the polarized light. With further increasing the POSS content (>50 wt%) in LCP-POSS, the ordered structure of the liquid crystalline phase was gradually affected, resulting in one-way liquid crystal (LC) phase behavior. The synthesized LCP-POSS has LC properties, light-responsive properties, and thermal stability. When the POSS is introduced into the LC material, the phase state of the LC material will become more abundant and the LC phase will become more stable. The significance of this study is to develop and extend its applications as stimuli-responsive materials and devices.

中文翻译:

多面体低聚倍半硅氧烷/侧链偶氮苯杂化共聚物的液晶性和热性能

摘要 通过多面体低聚倍半硅氧烷(POSS)中的胺基与丙烯酸反应合成了丙烯酸改性的多面体低聚倍半硅氧烷(AC-POSS),该化合物易溶于水,易于纯化。以不同比例的AC-POSS和液晶单体,采用自由基共聚反应合成偶氮苯液晶聚合物倍半硅氧烷(LCP-POSS)。随着紫外线照射时间的增加,LCP-POSS中偶氮苯部分的反式异构体逐渐转变为顺式异构体。液晶聚合物(LCP)和LCP-POSS的光异构化反应呈现一级动力学反应。与 LCP 相比,由于作为刚性链段的 POSS 的空间位阻,LCP-POSS 的光异构化速率常数降低。LCP-POSS液晶的相变温度随着POSS含量的增加而升高,LCP-POSS液晶结构在偏振光下变小。随着LCP-POSS中POSS含量的进一步增加(> 50 wt%),液晶相的有序结构逐渐受到影响,导致单向液晶(LC)相行为。合成的LCP-POSS具有液晶特性、光响应特性和热稳定性。当 POSS 被引入到 LC 材料中时,LC 材料的相态会变得更加丰富,LC 相会变得更加稳定。
更新日期:2020-09-11
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