Blue phase liquid crystals affected by graphene oxide modified with aminoazobenzol group
Blue phase liquid crystals affected by graphene oxide modified with aminoazobenzol group
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DOI：
10.1080/02678292.2015.1126862
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发表时间：
2016-01
期刊：
影响因子：
2.2
通讯作者：
Wei-kai Zhang;Xiaomei Wang;Dong Wang;Zhou Yang;Hong Gao;Yan Xing;Wanli He;H. Cao;Huai Yang-Hu
中科院分区：
文献类型：
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作者：
Wei-kai Zhang;Xiaomei Wang;Dong Wang;Zhou Yang;Hong Gao;Yan Xing;Wanli He;H. Cao;Huai Yang-Hu
摘要液晶蓝相（BP）仅在各向同性相和手性相之间的很窄的温度范围内是稳定的，这严重阻碍了它们的应用。在此，通过加成反应将氨基偶氮苯基团化学接枝到氧化石墨烯（GO）的环氧基团上。通过X射线光电子能谱（XPS）、傅里叶变换红外光谱（FTIR）、紫外-可见吸收光谱（UV-vis）和热重分析（TGA）证实了氨基偶氮苯基团的成功接枝。还原的所得氨基偶氮苯基团修饰的GO片（RGO-Az）可容易地再分散在普通有机溶剂或液晶（LC）中。通过掺杂不同含量的RGO-Az，纳米片可以稳定BP并增加BP范围。当掺杂有0.5wt% RGO-Az时，混合物显示出比没有RGO-Az的BPLC的3.6°C的范围更宽的5.9°C的范围。同时，上述相的相序列和范围在加热和冷却时是可再现的，这表明掺杂有RGO-Az纳米片的BP是热稳定的。图形摘要
ABSTRACT Liquid-crystalline blue phases (BPs) are stable only for very narrow temperature range between the isotropic and the chiral nematic phase that severely hinders their applicability. Herein, the aminoazobenzol group was chemically grafted onto epoxy group of graphene oxide (GO) via addition reaction. Successful grafting of aminoazobenzol group was confirmed using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), UV–vis absorption spectra and thermogravimetric analysis (TGA). The resultant aminoazobenzol group–modified GO sheets, which is reduced (RGO-Az), were easily redispersable in common organic solvents or liquid crystals (LCs). By doping different contents of RGO-Az, nanosheets could stabilise BP and increase the BP range. When doped with 0.5 wt% RGO-Az, the mixtures show the wider range with 5.9°C than the range with 3.6°C of BPLCs without RGO-Az. Meanwhile, the phase sequence and the range of the aforementioned phases are reproducible upon heating and cooling, which shows that the BPs doped with RGO-Az nanosheets are thermodynamically stable. GRAPHICAL ABSTRACT