|
ИСТИНА |
Войти в систему Регистрация |
ФНКЦ РР |
||
Rheology of highly ordered smectic phases based on biphenyl derivativesстатья
Статья опубликована в высокорейтинговом журнале
Статья опубликована в журнале из списка Web of Science и/или Scopus- Авторы: Ilyin Sergey O., Konstantinov Ivan I.
- Журнал: Journal of Molecular Liquids
- Том: 363
- Год издания: 2022
- Издательство: Elsevier BV
- Местоположение издательства: Netherlands
- Номер статьи: 119872
- DOI: 10.1016/j.molliq.2022.119872
- Аннотация: The rheological properties of five biphenyl derivatives have been considered in detail. These derivatives form smectic phases that differ greatly in structural ordering (smectics A, C, F, G, I*, and H*), including through polymorphic transformations. As the structural ordering increases, the flow behavior of smectics progressively shifts from liquid-like to solid-like but does not reach the behavior of a solid. In this respect, smectics A and C are viscoelastic shear-thinning fluids that have a yield stress but can flow at both low and high stresses. Moreover, the continuous shear can affect their phase equilibrium, either by initiating a transition to another phase state or conversely by suppressing the thermodynamically-possible transition. In contrast, phase state of well-ordered smectics are shear-independent and they only able to flow at low stresses, while high ones destroy them in a solid-like manner. However, the behavior of smectics at small deformations that do not destroy their structure does not change as clearly as the flow behavior. Smectics with random packing of molecules are gels, whereas the appearance of pseudohexagonal packing makes them liquid-like at long observation times, though simultaneously greatly increases their stiffness. The appearance of the long-range positional order eliminates the liquid-like properties and increases the stiffness, bringing it closer to that of polycrystals, whereas the additional herringbone molecular packing slightly reduces the stiffness.
- Добавил в систему: Ильин Сергей Олегович