National Key Laboratory of Biobased Transportation Fuel Technology, International Research Center for X Polymers, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China.
ACS Macro Lett. 2023 Jul 18;12(7):1005-1011. doi: 10.1021/acsmacrolett.3c00277. Epub 2023 Jul 6.
The phase structure with a small domain size in polymers is expected to provide a template for lithography to fabricate electronic devices, while the uniformity and thermal stability of the phase structure are vital in lithography. In this work, we report an accurately microphase-separated system of comb-like poly(ionic liquid) (PIL)-based homopolymers containing imidazolium cation junctions between the main chain parts and the long alkyl side chains, poly(1-((2-acryloyloxy)ethyl)-3-alkylimidazolium bromide) (P(AOEAI-Br)). The ordered hexagonally packed cylinder (HEX) and lamellar (LAM) structures with small domain sizes (sub-3 nm) were successfully achieved. Since the microphase separation was induced by the incompatibility between the main chain parts and the hydrophobic alkyl chains, the microdomain spacing of the ordered structure was independent of the molecular weight and molecular weight distribution of P(AOEAI-Br) homopolymers and could be precisely regulated by changing the length of the alkyl side chains. Importantly, the microphase separation was promoted by the charged junction groups; thus, the phase structure and domain size of P(AOEAI-Br) exhibited excellent thermal stability.
聚合物中具有小尺寸畴结构的相有望为用于制造电子器件的光刻提供模板，而相结构的均匀性和热稳定性在光刻中至关重要。在这项工作中，我们报告了一种精确的梳状聚（离子液体）（PIL）基均聚物的微相分离体系，该体系含有主链部分和长烷基侧链之间的离子键连接的咪唑阳离子接头，即聚（1-（（2-丙烯酰氧基）乙基）-3-烷基咪唑溴化物）（P（AOEAI-Br））。成功实现了具有小尺寸畴（亚 3nm）的规则六方柱状（HEX）和层状（LAM）结构。由于微相分离是由主链部分和疏水性烷基链之间的不相容性引起的，因此有序结构的微畴间距与 P（AOEAI-Br）均聚物的分子量和分子量分布无关，可以通过改变烷基侧链的长度来精确调节。重要的是，带电荷的连接基团促进了微相分离；因此，P（AOEAI-Br）的相结构和畴尺寸表现出优异的热稳定性。
