Iwasaki Kaede, Okoshi Masayuki
Department of Electrical and Electronic Engineering, National Defense Academy, 1-10-20 Hashirimizu, Yokosuka 239-8686, Japan.
Gels. 2023 Feb 24;9(3):179. doi: 10.3390/gels9030179.
It is expected that ionic liquids will be used in the future as electrolytes for electric double layer capacitors, but currently microencapsulation with a conductive or porous shell is required for their fabrication. Here, we succeeded in fabricating a transparently gelled ionic liquid trapped in hemispherical silicone microcup structures just by observing with a scanning electron microscope (SEM), which allows the microencapsulation process to be eliminated and electrical contacts to be formed directly. To see the gelation, small amounts of ionic liquid were exposed to the SEM electron beam on flat aluminum, silicon, silica glass, and silicone rubber. The ionic liquid gelled on all the plates, and a color change to brown was observed on all the plates except for silicone rubber. This change might be caused by reflected and/or secondary electrons from the plates producing isolated carbon. Silicone rubber could remove the isolated carbon due to the large amount of oxygen inside it. Fourier transform infrared spectroscopy revealed that the gelled ionic liquid included a large amount of the original ionic liquid. Moreover, the transparent, flat gelled ionic liquid could also be made into three-layer structures on silicone rubber. Consequently, the present transparent gelation is suitable for silicone rubber-based microdevices.
预计离子液体未来将用作双电层电容器的电解质，但目前其制造需要用导电或多孔壳进行微封装。在此，我们仅通过扫描电子显微镜（SEM）观察，成功制备出被困在半球形硅微杯结构中的透明凝胶化离子液体，这使得微封装过程得以省略，并能直接形成电接触。为观察凝胶化现象，将少量离子液体暴露于平板铝、硅、石英玻璃和硅橡胶上的SEM电子束下。离子液体在所有平板上均发生凝胶化，除硅橡胶外，在所有平板上均观察到颜色变为棕色。这种变化可能是由平板产生的反射电子和/或二次电子生成孤立碳所致。硅橡胶因其内部大量的氧可去除孤立碳。傅里叶变换红外光谱表明，凝胶化离子液体包含大量原始离子液体。此外，透明、扁平的凝胶化离子液体也可在硅橡胶上制成三层结构。因此，目前的透明凝胶化适用于基于硅橡胶的微器件。
