Abstract In this study, a series of novel ABA-type triblock azo-copolymers (TBCs) consisting of PEG and PCAEMA segments were synthesized by RAFT polymerization. The TBCs were characterized by 1H-NMR, GPC, DSC, OPM, AFM, GISAXS, and UV-vis. Number-average molecular weight (≤34,200 g/mol) and molecular weight distribution (≤1.44) were slightly increased with increasing the feed molar ratio of monomer to macroinitiator. This indicates a controlled/living polymerization with good distribution. All TBCs displayed transitions attributed to smectic-to-nematic and nematic-to-smectic phases at 108 °C and 104 °C, respectively. TBC with 34 wt% azobenzene displayed fan-shaped focal conic texture, while TBCs containing 46, 53, 58, 63, and 71 wt% azobenzene revealed batonnet textures. TBC-3 and TBC-4 having 53 and 58 wt% azo contents produced lamellar and a mixture of cylinder and lamellar nanostructures compared to other TBCs, which formed hexagonal cylindrical nanostructures. Every TBCs exhibited photoresponsive behavior under UV irradiation and thermal relaxation.

中文翻译：

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具有刚性和软链段的新型偶氮基 ABA 三嵌段共聚物的热退火 RAFT 合成、性能和形貌

摘要 在本研究中，通过 RAFT 聚合合成了一系列由 PEG 和 PCAEMA 链段组成的新型 ABA 型三嵌段偶氮共聚物 (TBCs)。通过 1H-NMR、GPC、DSC、OPM、AFM、GISAXS 和 UV-vis 对 TBC 进行表征。随着单体与大分子引发剂进料摩尔比的增加，数均分子量 (≤34,200 g/mol) 和分子量分布 (≤1.44) 略有增加。这表明具有良好分布的受控/活性聚合。所有 TBC 均显示出归因于 108 °C 和 104 °C 的近晶相到向列相和向列相到近晶相的转变。含有 34 wt% 偶氮苯的 TBC 显示出扇形焦锥纹理，而含有 46、53、58、63 和 71 wt% 偶氮苯的 TBC 显示出警棍网状纹理。与形成六边形圆柱纳米结构的其他TBC相比，具有53和58wt%偶氮含量的TBC-3和TBC-4产生层状以及圆柱和层状纳米结构的混合物。每个 TBC 在紫外线照射和热弛豫下都表现出光响应行为。