Impact of Weak Nanoparticle Induced Disorder on Nematic Ordering
Dilute mixtures of nanoparticles (NPs) and nematic liquid crystals (LCs) are considered. We focus on cases where NPs enforce a relatively weak disorder to the LC host. We use a Lebwohl-Lasher semi-microscopic-type modeling where we assume that NPs effectively act as a spatially-dependent external fi...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-03-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/9/3/171 |
| _version_ | 1798043324882354176 |
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| author | Dejvid Črešnar Christina Kyrou Ioannis Lelidis Aleksandra Drozd-Rzoska Szymon Starzonek Sylwester Janusz Rzoska Zdravko Kutnjak Samo Kralj |
| author_facet | Dejvid Črešnar Christina Kyrou Ioannis Lelidis Aleksandra Drozd-Rzoska Szymon Starzonek Sylwester Janusz Rzoska Zdravko Kutnjak Samo Kralj |
| author_sort | Dejvid Črešnar |
| collection | DOAJ |
| description | Dilute mixtures of nanoparticles (NPs) and nematic liquid crystals (LCs) are considered. We focus on cases where NPs enforce a relatively weak disorder to the LC host. We use a Lebwohl-Lasher semi-microscopic-type modeling where we assume that NPs effectively act as a spatially-dependent external field on nematic spins. The orientational distribution of locally favoured “easy„ orientations is described by a probabilistic distribution function <i>P</i>. By means of a mean field-type approach, we derive a self-consistent equation for the average degree of nematic uniaxial order parameter <i>S</i> as a function of the concentration <i>p</i> of NPs, NP-LC coupling strength and <i>P</i>. Using a simple step-like probability distribution shape, we obtain the <i>S</i>(<i>p</i>) dependence displaying a crossover behaviour between two different regimes which is in line with recent experimental observations. We also discuss a possible origin of commonly observed non-monotonous variations of the nematic-isotropic phase temperature coexistence width on varying <i>p</i>. |
| first_indexed | 2024-04-11T22:47:35Z |
| format | Article |
| id | doaj.art-e0f9eaeb456c42f09afec04b26633234 |
| institution | Directory Open Access Journal |
| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-04-11T22:47:35Z |
| publishDate | 2019-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Crystals |
| spelling | doaj.art-e0f9eaeb456c42f09afec04b266332342022-12-22T03:58:43ZengMDPI AGCrystals2073-43522019-03-019317110.3390/cryst9030171cryst9030171Impact of Weak Nanoparticle Induced Disorder on Nematic OrderingDejvid Črešnar0Christina Kyrou1Ioannis Lelidis2Aleksandra Drozd-Rzoska3Szymon Starzonek4Sylwester Janusz Rzoska5Zdravko Kutnjak6Samo Kralj7Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, SloveniaFaculty of Physics, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, 15784 Athens, GreeceFaculty of Physics, National and Kapodistrian University of Athens, Panepistimiopolis, Zografos, 15784 Athens, GreeceInstitute of High Pressure Physics, Polish Academy of Sciences, ul. Sokolowska 29/37, 01-142 Warsaw, PolandInstitute of High Pressure Physics, Polish Academy of Sciences, ul. Sokolowska 29/37, 01-142 Warsaw, PolandInstitute of High Pressure Physics, Polish Academy of Sciences, ul. Sokolowska 29/37, 01-142 Warsaw, PolandJožef Stefan Institute, Jamova 39, 1000 Ljubljana, SloveniaJožef Stefan Institute, Jamova 39, 1000 Ljubljana, SloveniaDilute mixtures of nanoparticles (NPs) and nematic liquid crystals (LCs) are considered. We focus on cases where NPs enforce a relatively weak disorder to the LC host. We use a Lebwohl-Lasher semi-microscopic-type modeling where we assume that NPs effectively act as a spatially-dependent external field on nematic spins. The orientational distribution of locally favoured “easy„ orientations is described by a probabilistic distribution function <i>P</i>. By means of a mean field-type approach, we derive a self-consistent equation for the average degree of nematic uniaxial order parameter <i>S</i> as a function of the concentration <i>p</i> of NPs, NP-LC coupling strength and <i>P</i>. Using a simple step-like probability distribution shape, we obtain the <i>S</i>(<i>p</i>) dependence displaying a crossover behaviour between two different regimes which is in line with recent experimental observations. We also discuss a possible origin of commonly observed non-monotonous variations of the nematic-isotropic phase temperature coexistence width on varying <i>p</i>.https://www.mdpi.com/2073-4352/9/3/171phase behaviourweak disorderorientational order |
| spellingShingle | Dejvid Črešnar Christina Kyrou Ioannis Lelidis Aleksandra Drozd-Rzoska Szymon Starzonek Sylwester Janusz Rzoska Zdravko Kutnjak Samo Kralj Impact of Weak Nanoparticle Induced Disorder on Nematic Ordering Crystals phase behaviour weak disorder orientational order |
| title | Impact of Weak Nanoparticle Induced Disorder on Nematic Ordering |
| title_full | Impact of Weak Nanoparticle Induced Disorder on Nematic Ordering |
| title_fullStr | Impact of Weak Nanoparticle Induced Disorder on Nematic Ordering |
| title_full_unstemmed | Impact of Weak Nanoparticle Induced Disorder on Nematic Ordering |
| title_short | Impact of Weak Nanoparticle Induced Disorder on Nematic Ordering |
| title_sort | impact of weak nanoparticle induced disorder on nematic ordering |
| topic | phase behaviour weak disorder orientational order |
| url | https://www.mdpi.com/2073-4352/9/3/171 |
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