Fu Da-Wei, Gao Ji-Xing, Huang Pei-Zhi, Ren Rui-Ying, Shao Ting, Han Li-Jun, Liu Jia, Gong Jun-Miao
Institute for Science and Applications of Molecular Ferroelectrics, Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal University, Jinhua, 321004, P. R. China.
Angew Chem Int Ed Engl. 2021 Apr 6;60(15):8198-8202. doi: 10.1002/anie.202015219. Epub 2021 Mar 3.
Organic ferroelectrics are highly desirable for their light weight, mechanical flexibility and biocompatibility. However, the rational design of organic ferroelectrics has always faced great challenges. Anilinium bromide (AB) has two structures reported in the Cambridge Crystallographic Data Centre, which might be an mmmF2/m type ferroelastic (AB-1). When we studied its ferroelasticity, we were surprised to discover that there was another crystal (AB-2) in H O besides this one, and they were very difficult to separate. By changing the solvent, we found that AB-1 crystals could be formed in ethanol, where ferroelastic domains were visualized by polarized light microscopy, and AB-2 crystals could be obtained from various crystallization solvents of methanol, isopropanol, N-butanol, acetonitrile, dimethyl sulfoxide, and N,N-dimethylformamide, which undergo a ferroelectric phase transition with mm2Fm, showing clear ferroelectricity in two phases. To our knowledge, the regulation of ferroelasticity to ferroelectricity by solvent selective effect is unprecedented in the field of ferroelectrics. This work reveals the important role of solvent effect in organic ferroelectrics.
有机铁电体因其重量轻、机械柔韧性和生物相容性而备受青睐。然而，有机铁电体的合理设计一直面临巨大挑战。溴化苯胺（AB）在剑桥晶体学数据中心有两种结构报道，其中一种可能是mmmF2/m型铁弹体（AB-1）。当我们研究其铁弹性时，惊讶地发现在水中除了这种晶体外还有另一种晶体（AB-2），而且它们很难分离。通过改变溶剂，我们发现AB-1晶体可以在乙醇中形成，在偏光显微镜下可以观察到铁弹畴，而AB-2晶体可以从甲醇、异丙醇、正丁醇、乙腈、二甲基亚砜和N，N-二甲基甲酰胺等各种结晶溶剂中获得，它们经历mm2Fm铁电相变，在两个相中显示出明显的铁电性。据我们所知，通过溶剂选择效应将铁弹性调控为铁电性在铁电体领域是前所未有的。这项工作揭示了溶剂效应在有机铁电体中的重要作用。
