Large twist elastic constant in diphenylacetylene-core-based liquid crystals
Large twist elastic constant in diphenylacetylene-core-based liquid crystals
复制标题
二苯乙炔核液晶中的大扭转弹性常数
DOI：
10.1080/15421406.2015.1050289
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
H. Takezoe
中科院分区：
文献类型：
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作者：
K. V. Le;S. Aya;S. Ogino;K. Okano;F. Araoka;H. Takezoe
我们测定了两种含偶氮和酯键的二苯乙炔核基液晶的弹性常数K11、K22和K33。正如我们已经报道的那样（Adv. Mater。（2014）26，1918），在偶氮化合物中，K33与K11（pN）相比是非常大的（sub-nN），因为半规整近晶（Sm）簇存在于整个N相范围内。作为一个自然的结果，K22预计也很大。我们确定K22为几十pN，比K33小，比K11大一个数量级，K33>>K22>>K11。这是第一个化合物，其K22大于K11。在N相中没有团簇的酯化合物中，所有的弹性常数都在pN范围内，并且按通常的顺序，K33>K11>K22。当接近N-SmC相变温度时，不仅K33和K22，而且K11都表现出相变前的增加。
We determine elastic constantsK11,K22, andK33in two diphenylacetylene-core-based liquid crystals with azo and ester linkages. As we have already reported (Adv. Mater. (2014)26, 1918),K33is extremely large (sub-nN) compared withK11(pN) in the azo compound, since cybotactic smectic (Sm) clusters exist in whole the nematic (N) phase range. As a natural consequence,K22is expected to be also large. We confirm thatK22is several tens pN, which is smaller thanK33but larger thanK11by one order of magnitude,K33>>K22>>K11. This is the first compound, which has a largerK22thanK11. In the ester compound, which has no clusters in the N phase, all the elastic constants are in a pN range, and are in the usual order,K33>K11>K22. It is also important to note that not onlyK33andK22but alsoK11show a pretransitional increase when the N-SmC phase transition temperature is approached.