Confinement effects on lyotropic nematic liquid crystal phases of graphene oxide dispersions
Confinement effects on lyotropic nematic liquid crystal phases of graphene oxide dispersions
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DOI：
10.1088/2053-1583/aa843a
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发表时间：
2017-12-01
期刊：
影响因子：
5.5
通讯作者：
Dierking, Ingo
中科院分区：
文献类型：
--
作者：
Al-Zangana, Shakhawan;Iliut, Maria;Dierking, Ingo
氧化石墨烯（GO）在极性溶剂中形成良好有序的液晶（LC）相。在这里，我们绘制了GO的溶致相图作为GO薄片的横向尺寸、它们的浓度、几何限制配置和溶剂极性的函数。在水中制备GO薄片并转移到其他极性溶剂中。使用偏振光学显微镜（POM）来确定通过GO LC的各向同性-双相-双相转变的相演变。我们报告说，相对于颗粒大小的限制体积和几何形状对于观察溶致相是至关重要的，具体地说，这决定了GO LC检测的低端浓度极限。此外，具有较高极化率的溶剂在较低浓度和较小薄片尺寸下稳定LC相。已经提出了GO LC用于从显示技术到导电纤维的一系列应用，并且在限制下LC相形成的行为对这种GO LC系统的尺寸的结晶化施加了限制，这可能显著影响其潜在的应用。
Graphene oxide (GO) forms well ordered liquid crystal (LC) phases in polar solvents. Here, we map the lyotropic phase diagram of GO as a function of the lateral dimensions of the GO flakes, their concentration, geometrical confinement configuration and solvent polarity. GO flakes were prepared in water and transferred into other polar solvents. Polarising optical microscopy (POM) was used to determine the phase evolution through the isotropic-biphasic-nematic transitions of the GO LC. We report that the confinement volume and geometry relative to the particle size is critical for the observation of the lyotropic phase, specifically, this determines the low-end concentration limit for the detection of the GO LC. Additionally, a solvent with higher polarisability stabilises the LC phases at lower concentrations and smaller flake sizes. GO LCs have been proposed for a range of applications from display technologies to conductive fibres, and the behaviour of LC phase formation under confinement imposes a limit on miniaturisation of the dimensions of such GO LC systems which could significantly impact on their potential applications.