Stimuli-responsive hybrid materials: breathing in magnetic layered double hydroxides induced by a thermoresponsive molecule.
Stimuli-responsive hybrid materials: breathing in magnetic layered double hydroxides induced by a thermoresponsive molecule.
复制标题
DOI：
10.1039/c4sc03460k
复制
发表时间：
2015-03-01
期刊：
影响因子：
8.4
通讯作者：
Coronado E
中科院分区：
文献类型：
--
作者：
Abellán G;Jordá JL;Atienzar P;Varela M;Jaafar M;Gómez-Herrero J;Zamora F;Ribera A;García H;Coronado E
制备了一种由CoAl-LDH铁磁层和温敏分子组成的混合磁性多层膜材料。制备了一种微米尺寸的混合磁性多层膜材料，该材料具有高度结晶的六方晶体，由CoAl-LDH铁磁层和用柔性十二烷基硫酸钠（SDS）表面活性剂稀释（9：1）的温敏4-（4-苯胺基苯偶氮）苯磺酸盐（AO5）分子组成。所得材料表现出热致变色性，这归因于偶氮（在室温下普遍存在）和腙（在较高温度下有利）互变异构体之间的异构化，导致热机械响应。事实上，这些晶体表现出热致运动触发晶体形态和体积的显着变化。这些薄的混合物的原位变温XRD显示，两种互变异构体的可逆变化反映在对于腙形式的衍射峰的位置在高温下朝向较低层间间距的移位，以及反映较低结晶度和由于层之间的不均匀间距导致的有序的峰的加宽。室温（基底间距（BS）= 25.91 nm）和100 ℃（BS = 25.05 nm）之间的这些结构变化也反映在层状双氢氧化物（LDH）的磁性中，这是由于层之间的磁耦合的变化。总的来说，我们的研究是少数几个在2D混合材料中显示完全可逆的热响应呼吸的例子之一。此外，由于有机组分的向热性，可以调节混合物的磁响应，通过影响无机LDH的距离和面内相关性，在一定范围内调节CoAl-LDH片的磁性。
A hybrid magnetic multilayer material consisting of CoAl–LDH ferromagnetic layers intercalated with thermoresponsive molecules diluted with a flexible surfactant has been obtained. A hybrid magnetic multilayer material of micrometric size, with highly crystalline hexagonal crystals consisting of CoAl–LDH ferromagnetic layers intercalated with thermoresponsive 4-(4-anilinophenylazo)benzenesulfonate (AO5) molecules diluted (ratio 9 : 1) with a flexible sodium dodecylsulphate (SDS) surfactant has been obtained. The resulting material exhibits thermochromism attributable to the isomerization between the azo (prevalent at room temperature) and the hydrazone (favoured at higher temperatures) tautomers, leading to a thermomechanical response. In fact, these crystals exhibited thermally induced motion triggering remarkable changes in the crystal morphology and volume. In situ variable temperature XRD of these thin hybrids shows that the reversible change into the two tautomers is reflected in a shift of the position of the diffraction peaks at high temperatures towards lower interlayer spacing for the hydrazone form, as well as a broadening of the peaks reflecting lower crystallinity and ordering due to non-uniform spacing between the layers. These structural variations between room temperature (basal spacing (BS) = 25.91 Å) and 100 °C (BS = 25.05 Å) are also reflected in the magnetic properties of the layered double hydroxide (LDH) due to the variation of the magnetic coupling between the layers. Overall, our study constitutes one of the few examples showing fully reversible thermo-responsive breathing in a 2D hybrid material. In addition, the magnetic response of the hybrid can be modulated due to the thermotropism of the organic component that, by influencing the distance and in-plane correlation of the inorganic LDH, modulates the magnetism of the CoAl–LDH sheets in a certain range.