Effect of the network density on dynamics ...
Document type :
Article dans une revue scientifique: Article original
PMID :
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Title :
Effect of the network density on dynamics of the soft and the Goldstone modes in short-pitch ferroelectric liquid crystals stabilized by an anisotropic polymer network
Author(s) :
Petit, Mohamed [Auteur]
Hemine, Jamal [Auteur]
Daoudi, Abdelylah [Auteur]
Ismaili, Mimoun [Auteur]
Buisine, Jean-Marc [Auteur]
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Da Costa, Antonio [Auteur]
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Hemine, Jamal [Auteur]
Daoudi, Abdelylah [Auteur]
Ismaili, Mimoun [Auteur]
Buisine, Jean-Marc [Auteur]
![refId](/themes/Mirage2//images/idref.png)
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Da Costa, Antonio [Auteur]
![refId](/themes/Mirage2//images/idref.png)
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]
Journal title :
Physical Review E : Statistical, Nonlinear, and Soft Matter Physics
Abbreviated title :
Phys. Rev. E
Volume number :
79
Publication date :
2009-03-30
ISSN :
1539-3755
English keyword(s) :
smectic liquid crystals
liquid-liquid transformations
liquid crystal polymers
ferroelectric liquid crystals
electric strength
dielectric relaxation
liquid-liquid transformations
liquid crystal polymers
ferroelectric liquid crystals
electric strength
dielectric relaxation
HAL domain(s) :
Chimie
English abstract : [en]
We report the influence of the polymer network density formed in short-pitch ferroelectric liquid crystal (FLC) on the soft and the Goldstone dielectric relaxation modes. The experimental results of the pure FLC and the ...
Show more >We report the influence of the polymer network density formed in short-pitch ferroelectric liquid crystal (FLC) on the soft and the Goldstone dielectric relaxation modes. The experimental results of the pure FLC and the FLC stabilized by a polymer network with various densities are presented and compared. These results reveal that in the SmC∗ phase, when the polymer concentration increases, the Goldstone dielectric strength gradually decreases and the relaxation frequency is shifted to higher values. In the SmA∗ phase, the results show that close to the SmC∗-SmA∗ transition temperature, Tc, the soft relaxation mode is largely influenced by the polymer network: a sharp decrease in the dielectric strength and an increase in the relaxation frequency when the polymer density increases were observed. The soft mode is relatively weakly affected by the network for higher temperatures (T≥Tc+0.5 °C). This indicates that the behavior of the soft mode for this temperature domain is dominated rather by thermal effects than by the network. A simple phenomenological approach was proposed to explain the behavior of the soft-mode dielectric strength versus polymer concentration. This model takes into account the anisotropic interaction between the polymer network and the liquid crystal, and the elastic interaction resulting from the anchoring of the liquid crystal molecules at the polymer surfaces. The experimental results are in agreement with the proposed model.Show less >
Show more >We report the influence of the polymer network density formed in short-pitch ferroelectric liquid crystal (FLC) on the soft and the Goldstone dielectric relaxation modes. The experimental results of the pure FLC and the FLC stabilized by a polymer network with various densities are presented and compared. These results reveal that in the SmC∗ phase, when the polymer concentration increases, the Goldstone dielectric strength gradually decreases and the relaxation frequency is shifted to higher values. In the SmA∗ phase, the results show that close to the SmC∗-SmA∗ transition temperature, Tc, the soft relaxation mode is largely influenced by the polymer network: a sharp decrease in the dielectric strength and an increase in the relaxation frequency when the polymer density increases were observed. The soft mode is relatively weakly affected by the network for higher temperatures (T≥Tc+0.5 °C). This indicates that the behavior of the soft mode for this temperature domain is dominated rather by thermal effects than by the network. A simple phenomenological approach was proposed to explain the behavior of the soft-mode dielectric strength versus polymer concentration. This model takes into account the anisotropic interaction between the polymer network and the liquid crystal, and the elastic interaction resulting from the anchoring of the liquid crystal molecules at the polymer surfaces. The experimental results are in agreement with the proposed model.Show less >
Language :
Anglais
Audience :
Internationale
Popular science :
Non
Administrative institution(s) :
Université de Lille
CNRS
Centrale Lille
ENSCL
Univ. Artois
CNRS
Centrale Lille
ENSCL
Univ. Artois
Collections :
Submission date :
2023-05-30T18:06:04Z
2024-04-25T14:04:58Z
2024-04-25T14:04:58Z