Rheology of Liquid Crystalline Elastomers in Their Isotropic and Smectic A State
Rheology of Liquid Crystalline Elastomers in Their Isotropic and Smectic A State
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液晶弹性体各向同性和近晶 A 状态的流变学
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发表时间：
1999
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通讯作者：
P. Martinoty
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作者：
J. Weilepp;J. Zanna;N. Aßfalg;P. Stein;L. Hilliou;M. Mauzac;H. Finkelmann;H. Brand;P. Martinoty
通过低频剪切和压缩实验研究了两种不同的近晶A相侧链液晶弹性体（SCLCE）的动力学行为。我们发现，各向同性和近晶A相有自己的特征粘弹性行为，这似乎是独立的化合物下的调查，因此普遍。在各向同性相的弛豫示出了弛豫时间的分布，这引起了指数为0.5的弹性模量的标度律。然而，在近晶A相的粘弹性响应，表现出更广泛的弛豫时间的频谱包含非常长的寿命模式。它似乎存在一个低频标度律与指数为0.3表征近晶A相。我们建议，这一结果源于一个短暂的近晶网络具有很长的寿命，是由近晶域。在相变时，这种瞬态近晶网络消失，导致了一个尖锐的缺陷。
The dynamics of two different side-chain liquid crystalline elastomers (SCLCE) exhibiting a smectic A phase is investigated by low-frequency shear and compression experiments. We find that both the isotropic and the smectic A phase have their own characteristic viscoelastic behavior, which seems to be independent of the compound under investigation and thus universal. The relaxation in the isotropic phase shows a distribution of relaxation times, which gives rise to a scaling law of the elastic moduli with an exponent of 0.5. The viscoelastic response in the smectic A phase, however, exhibits a much broader spectrum of relaxation times containing very long-lived modes. It appears that there exists a low-frequency scaling law with an exponent of 0.3 characterizing the smectic A phase. We propose that this result stems from a transient smectic network with a very long lifetime that was set up by the smectic domains. At the phase transition, this transient smectic network disappears, which leads to a sharp d...