Magnetic segregation effect in liquid crystals doped with carbon nanotubes

• Danil A. Petrov,
• Pavel K. Skokov,
• Alexander N. Zakhlevnykh and
• Dmitriy V. Makarov

Beilstein J. Nanotechnol. 2019, 10, 1464–1474, doi:10.3762/bjnano.10.145

• feature of CNTs is their strong diamagnetism ( ≈ 10−5 to 10−4) [18][19][20][21][22][23]. In the majority of experimental publications [7][16][24][25][26] the planar type of anchoring between the nanotubes and the LC matrix is noted. For CNT suspensions based on nematic liquid crystals (NLCs) with positive

Threshold voltage decrease in a thermotropic nematic liquid crystal doped with graphene oxide flakes

• Mateusz Mrukiewicz,
• Krystian Kowiorski,
• Paweł Perkowski,
• Rafał Mazur and
• Małgorzata Djas

Beilstein J. Nanotechnol. 2019, 10, 71–78, doi:10.3762/bjnano.10.7

• permittivity measured along the directions parallel and perpendicular to n, respectively. In the case of positive electric anisotropy (Δε > 0), the director is forced to align along the electric field. One of the most efficient methods to reduce the threshold voltage in nematic liquid crystals for high electro

• areas. Therefore, the main advantage of GO is easy dispersibility in water and organic solvents [23][25]. Graphene oxide occurs in the form of two-dimensional flakes with anisotropic properties [24]. In thermotropic nematic liquid crystals, GO flakes create dipoles due to Maxwell–Wagner polarization [26

• wt %) we observed the opposite effect. The structure was stiffened due to the strong interaction of NLC-GO. However, at a higher concentration (0.3 wt %) we noticed the reduction of the threshold voltage because of the significant increase of the rotational viscosity. Nematic liquid crystals with

Nanostructured liquid crystal systems and applications

• Alexei R. Khokhlov and
• Alexander V. Emelyanenko

Beilstein J. Nanotechnol. 2018, 9, 2644–2645, doi:10.3762/bjnano.9.245

• indicates that investigations of liquid crystals on the nanoscale are essential for the survival and development of civilization. Most everyone today in the modern world uses multiple display devices (e.g., TV, computer monitors, smartphones, projectors). Most of such displays are based on nematic liquid

• crystals, in which each pixel consists of the three sub-pixels (red, green and blue), and thus, up to 2/3 of the backlight can be absorbed by the color filters. Although the energy consumption by each display does not appear to be very large, with the whole human population using displays, this results in

Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

• Margarita A. Kurochkina,
• Elena A. Konshina and
• Daria Khmelevskaia

Beilstein J. Nanotechnol. 2018, 9, 1544–1549, doi:10.3762/bjnano.9.145

Induced smectic phase in binary mixtures of twist-bend nematogens

• Anamarija Knežević,
• Irena Dokli,
• Marin Sapunar,
• Suzana Šegota,
• Ute Baumeister and
• Andreja Lesac

Beilstein J. Nanotechnol. 2018, 9, 1297–1307, doi:10.3762/bjnano.9.122

• compound has the desired properties for a particular application. Since the discovery that mixtures of nematic compounds could yield room-temperature nematic liquid crystals [1], the mixing of LC compounds became a very useful technique. Thus, investigation of LC mixtures is of great interest in targeting

Formation and development of nanometer-sized cybotactic clusters in bent-core nematic liquid crystalline compounds

• Yuri P. Panarin,
• Sithara P. Sreenilayam,
• Jagdish K. Vij,
• Anne Lehmann and
• Carsten Tschierske

Beilstein J. Nanotechnol. 2018, 9, 1288–1296, doi:10.3762/bjnano.9.121

• the samples was stabilized to within a range of ±0.02 °C. Results and Discussion The bent-core nematic liquid crystals were previously investigated by dielectric spectroscopy for determining the elastic and viscosity constants [54], as well as the molecular dipole moment [55]. The short-range polar

Optical orientation of nematic liquid crystal droplets via photoisomerization of an azodendrimer dopant

• Sergey A. Shvetsov,
• Alexander V. Emelyanenko,
• Natalia I. Boiko,
• Alexander S. Zolot'ko,
• Yan-Song Zhang,
• Jui-Hsiang Liu and
• Alexei R. Khokhlov

Beilstein J. Nanotechnol. 2018, 9, 870–879, doi:10.3762/bjnano.9.81

• different kinds of soft matter, such as light-driven polymers [5][6], elastomers [7][8][9] microgel particles [10][11], micelles [12][13], nematic liquid crystals (NLCs) [7][14], liquid-crystalline (LC) polymers [15][16][17][18] and Langmuir–Blodgett films [19][20] with light-controllable supramolecular

Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields

• Emil Petrescu,
• Cristina Cirtoaje and
• Octavian Danila

Beilstein J. Nanotechnol. 2018, 9, 399–406, doi:10.3762/bjnano.9.39

• on a sample containing 0.89% (mass fraction) of CdSe/ZnS quantum dots revealed a decrease of the relaxation time compared to pure 5CB. Keywords: Fréedericksz transition; nematic liquid crystals; quantum dots; Introduction The expansion of liquid crystal (LC)-based devices in common life domains as

• the field is switched off. Acknowledgements The work has been funded by University Politehnica of Bucharest, through the ’Excellence Research Grants’ Program, UPB–GEX. Identifier: UPB–EXCELENŢĂ–2016 Research project title Phase modulation in nematic liquid crystals subjected to magnetic field

Dynamic behavior of a nematic liquid crystal with added carbon nanotubes in an electric field

• Emil Petrescu and
• Cristina Cirtoaje

Beilstein J. Nanotechnol. 2018, 9, 233–241, doi:10.3762/bjnano.9.25

• theoretical model based on elastic continuum theory was developed and the relaxation times of nematic liquid crystals with CNTs were evaluated. Experiments made with single-walled carbon nanotubes dispersed in nematic 4-cyano-4’-pentylbiphenyl (5CB) indicated a significant difference of the relaxation time

• present a simplified theoretical model to explain the behavior of nematic liquid crystals with added carbon nanotubes in an external electric field. This model is in good agreement with our experimental results but also with other published studies. Thus, a proper characterization of these nanomaterial

• the 5CB + SWCNTs mixture. Acknowledgements The work has been funded by University Politehnica of Bucharest, through the ’Excellence Research Grants’ Program, UPB–GEX. Identifier: UPB–EXCELENŢĂ–2016 Research project title Phase modulation in nematic liquid crystals subjected to magnetic field

Nematic topological defects positionally controlled by geometry and external fields

• Pavlo Kurioz,
• Marko Kralj,
• Bryce S. Murray,
• Charles Rosenblatt and
• Samo Kralj

Beilstein J. Nanotechnol. 2018, 9, 109–118, doi:10.3762/bjnano.9.13

• functional nanodevices. Keywords: nanoparticles; nematic liquid crystals; topological charge; topological defects; Introduction Topological defects (TDs) [1] represent an interdisciplinary research area [2] that is of high interest for nearly all branches of science. Due to their topological origin they

Magnetic field induced orientational transitions in liquid crystals doped with carbon nanotubes

• Danil A. Petrov,
• Pavel K. Skokov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2807–2817, doi:10.3762/bjnano.8.280

• ferroelectric particles, as well as of carbon nanotubes. In 1970, Brochard and de Gennes proposed to dope nematic liquid crystals (NLCs) with elongated ferromagnetic particles [3]. The magnetic susceptibility of such composite system (called ferronematic), turned out to be several orders of magnitude higher

Impact of titanium dioxide nanoparticles on purification and contamination of nematic liquid crystals

• Dmitrii Pavlovich Shcherbinin and
• Elena A. Konshina

Beilstein J. Nanotechnol. 2017, 8, 2766–2770, doi:10.3762/bjnano.8.275

• contamination of liquid crystals. Nematic liquid crystals with high and low initial ionic contamination have been examined. It has been shown that titanium dioxide nanoparticles reduced the ion density of liquid crystals with high initial ionic contamination from 134.5 × 1012 cm−3 to 63.2 × 1012 cm−3. In the

• contamination. We have examined nematic liquid crystals with low (LC1) and high (LC2) ionic contamination and their composites with TiO2 nanoparticles. The impact of TiO2 nanoparticles on purification and contamination in LCs has been experimentally shown. The plane-parallel cells consisted of two glass

Alternating current magnetic susceptibility of a ferronematic

• Natália Tomašovičová,
• Jozef Kováč,
• Veronika Gdovinová,
• Nándor Éber,
• Tibor Tóth-Katona,
• Jan Jadżyn and
• Peter Kopčanský

Beilstein J. Nanotechnol. 2017, 8, 2515–2520, doi:10.3762/bjnano.8.251

• attention that nematic liquid crystals (LCs) have attracted in recent decades is due to the anisotropy of their physical properties. This anisotropy allows for a realignment of their director (the axis of cylindrical symmetry) by external electrical or magnetic fields, or by shear [1]. In common nematics

Dynamic behavior of a nematic liquid crystal mixed with CoFe₂O₄ ferromagnetic nanoparticles in a magnetic field

• Emil Petrescu,
• Cristina Cirtoaje and
• Cristina Stan

Beilstein J. Nanotechnol. 2017, 8, 2467–2473, doi:10.3762/bjnano.8.246

• theoretical analysis of suspensions of ferromagnetic particles in water, the so-called ferrofluids [1], or in liquid crystals [2][3][4][5][6][7][8], as well as in related experimental studies [9][10]. Optical phase modulation can be easily achieved in nematic liquid crystals (LC) subjected to external fields

• the support area. This new structure obtained inside the cell exhibits a different Fréedericksz transition and a shorter response time compared to a pure 5CB nematic cell. Theoretical background Nematic liquid crystals are uniaxial crystals. When placed between crossed polarizers and passed through by

• –EXCELENŢĂ–2016 Research project title “Phase modulation in nematic liquid crystals subjected to magnetic fields”, contract number 24/26.09.2016.