Anisotropic chemical wave propagation of self-oscillating Belousov–Zhabotinsky (BZ) reaction was demonstrated in the poly(N-isopropylacrylamide) gel films embedded with macroscopically aligned liquid crystalline inorganic nanosheets. Although the average propagation rate of chemical wave v̅ was 3.56 mm min^–1 in the gels without nanosheets, the propagation was retarded in the gels with 1 wt % of nanosheets: = 1.89 mm min^–1 and = 1.33 mm min^–1 along the direction parallel and perpendicular to the nanosheet planes, respectively. Thus, the wave propagation is anisotropic with the anisotropy ratio = 1.42 in these gels and the periodic patterns formed by the BZ reaction were concentric ellipses, different from circles seen in isotropic gels. Furthermore, the propagation rate and degree of anisotropy were controllable by nanosheet concentration. These phenomena can be explained that the diffusion of molecules inside the gel is effectively hindered along the direction perpendicular to the nanosheet planes due to the very large aspect ratio of the aligned nanosheets. The present systems will be applicable for anisotropic self-oscillating soft actuators with one-dimensional motions as well as for ideal model system of BZ reactions.

中文翻译：

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液晶纳米片水凝胶中的各向异性自激反应

自振荡的Belousov-Zhabotinsky（BZ）反应的各向异性化学波传播在嵌入了宏观取向液晶无机纳米片的聚N-异丙基丙烯酰胺凝胶薄膜中得到证明。虽然化学波的平均传播速度v̅为3.56 mm最小^-1在凝胶中没有纳米片，所述传播延迟是在凝胶与纳米片的1％（重量）：=1.89毫米分钟^-1和= 1.33 mm最小^-1沿分别平行和垂直于纳米片平面的方向。因此，波的传播是各向异性的，具有各向异性比在这些凝胶中= 1.42，由BZ反应形成的周期性模式是同心椭圆，不同于在各向同性凝胶中看到的圆圈。此外，通过纳米片浓度可以控制传播速率和各向异性程度。这些现象可以解释为，由于排列的纳米片的纵横比非常大，沿垂直于纳米片平面的方向有效地阻止了分子在凝胶内的扩散。本系统将适用于具有一维运动的各向异性自振荡软致动器以及BZ反应的理想模型系统。