Article
Crystallography
Mikhail A. A. Osipov, Alexey S. S. Merekalov, Alexander A. A. Ezhov
Summary: In this study, the effect of rod-like nanoparticles on the high-frequency dielectric susceptibility of nematic nano-composites was investigated using a molecular theory. Analytical expressions for the effective polarizability of the nanoparticles in the nematic host were obtained and used to calculate the dielectric susceptibility of the composites as a function of the nanoparticle volume fraction. Numerical calculations were performed using a nematic liquid crystal as the host doped with gold or silver particles at different concentrations. The results showed that rod-like nanoparticles have a significant impact on the dielectric susceptibility of the nano-composites, especially in the case of gold nanoparticles near the plasmon resonance. The main conclusion is that at high nanoparticle concentrations, the anisotropy of the dielectric susceptibility of the nano-composites can even change sign, which has important implications for various applications.
Article
Materials Science, Multidisciplinary
Dhananjay Kumar Gaur, Kaushlendra Agrahari, Bhupendra Pratap Singh, Md Bayazeed Alam, Avanish Singh Parmar, Rajiv Manohar, Shri Singh
Summary: The effect of dispersion of polyvinyl pyrrolidone (PVP) capped gold nanoparticles in nematic mixture E7 on the optical properties and zeta potential is studied. The absorbance and photoluminescence intensity of dispersed systems are found to increase with gold nanoparticle concentration. The fluorescence lifetime of the dispersed systems confirms energy transfer between E7 and GNPs molecules. The orientation-dependent Raman spectrum intensity variation is also observed.
Article
Multidisciplinary Sciences
Runa Koizumi, Dmitry Golovaty, Ali Alqarni, Bing-Xiang Li, Peter J. Sternberg, Oleg D. Lavrentovich
Summary: The morphogenesis of living systems involves unusual topological shape transformations. In this study, a droplet of a nematic liquid crystal changes its equilibrium shape from a simply connected tactoid to a torus. This topological transformation is caused by the interplay of nematic elastic constants, facilitating splay and bend of molecular orientations in tactoids but hindering splay in toroids. This elastic anisotropy mechanism provides insights into topology transformations in morphogenesis and opens possibilities for controlling and transforming the shapes of liquid crystal droplets and related soft materials.
Article
Nanoscience & Nanotechnology
Zemin He, Ping Yu, Huimin Zhang, Yuzhen Zhao, Yanfang Zhu, Zhun Guo, Cheng Ma, Haiquan Zhang, Zongcheng Miao, Wenbo Shen
Summary: This study investigates the regulation of electric-optical performance in polymer/nematic liquid crystal composites by doping two silicon nanostructures. SiO2 nanoparticles are physically dispersed in the composites, while a nanostructure from POSS-SH is implanted into the polymer matrix via photoinduced crosslinking. Results show that the introduction of POSS microstructure helps to obtain uniform porous polymer microstructures, while SiO2 nanoparticles lead to loose and heterogeneous polymer morphologies. The electric-optical performance tests demonstrate that the regulation effect of POSS microstructure is more significant than that of SiO2 nanoparticles.
Article
Multidisciplinary Sciences
Fereshteh L. Memarian, Joseph D. Lopes, Fabian Jan Schwarzendahl, Madhuvanthi Guruprasad Athani, Niranjan Sarpangala, Ajay Gopinathan, Daniel A. Beller, Kinjal Dasbiswas, Linda S. Hirst
Summary: The study demonstrates the formation of dynamic lanes and long-range active nematic alignment by directly coupling kinesin motors to a lipid bilayer during microtubule gliding. The lipid membrane promotes filament-filament alignment and enhances globally aligned active nematic state formation.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Multidisciplinary Sciences
Ziga Kos, Joern Dunkel
Summary: In this study, the concept of nematic bits (nbits) is introduced in liquid crystals, and it is demonstrated through theory and simulations how single-bit operations can be implemented using electric fields and how universal classical logic gates and generalized logical functions can be realized using nematoelastic interactions.
Article
Crystallography
Kosuke Kaneko, Kosuke Yamashita, Daiki Fujioka, Kimiyoshi Kaneko, Kiyomi Fuchigami, Takeshi Hashishin, Tomonori Hanasaki
Summary: The electrorheological properties of composite materials consisting of a nematic liquid crystal (LC) and gold nanoparticles (GNPs) coated with bistolane-based mesogenic groups were studied. The presence of GNPs led to a slightly enhanced ER effect compared to the nematic LC alone. The study demonstrates the potential of a hybrid system consisting of LCs and GNPs to yield a larger ER effect.
Article
Chemistry, Physical
Kelum Perera, Rony Saha, Pawan Nepal, Rohan Dharmarathna, Md Sakhawat Hossain, Md Mostafa, Alex Adaka, Ronan Waroquet, Robert J. Twieg, Antal Jakli
Summary: The experimental results and theoretical considerations of novel electromechanical effects of ferroelectric nematic liquid crystal droplets coexisting with the isotropic melt are presented in this study. It is found that the droplets have flat pancake-like shapes thinner than the sample thickness. A wing-shaped defect with low birefringence is present in the center of the droplets, moving perpendicular to a weak electric field, and dividing into two at higher fields. The entire droplet drifts along the electric field with a speed independent of droplet size and proportional to the electric field amplitude.
Article
Crystallography
Mikhail A. Osipov, Alexey S. Merekalov, Alexander A. Ezhov
Summary: A molecular field theory was developed for the cholesteric ordering in nematic nanocomposites doped with chiral nanoparticles, taking into account the chiral dispersion interaction between rod-like nanoparticles. It was found that the inverse pitch of the cholesteric helical structure is proportional to the anisotropy of the effective polarizability and the effective gyration tensor of a nanoparticle in the nematic host. The theory can predict the inversion of helical sense induced by changes in the low-frequency dielectric susceptibility of the nematic host phase, with numerical calculations of the high-frequency effective polarizability and effective optical activity of gold rod-like nanoparticles in a specific nematic solvent.
Article
Multidisciplinary Sciences
Tianyi Yao, Ziga Kos, Qi Xing Zhang, Yimin Luo, Edward B. Steager, Miha Ravnik, Kathleen J. Stebe
Summary: Topological defects on rotating colloids in nematic liquid crystals form far-from-equilibrium structures that perform complex swim strokes, generating translation from rotation. The swimmer's speed and direction are determined by the topological defect's polarity and extent of elongation. Control over particle trajectories can be achieved by manipulating the elongation of defects using a rotating external magnetic field. The anisotropic viscosities associated with the defect elongation, lubrication forces, and line tensions between the colloid and the bounding surfaces contribute to the swimmers' translational motion and interaction.
Article
Chemistry, Physical
Katarina Zakutanska, Dmytro Miakota, Veronika Lackova, Shie-Chang Jeng, Dorota Weglowska, Filippo Agresti, Marketa Jarosova, Peter Kopcansky, Natalia Tomasovicova
Summary: This paper investigates the electromechanical and magnetomechanical memory effects induced by electric and magnetic fields in liquid crystal doped with aerosil nanoparticles. The systems studied exhibit hysteresis in capacitance-voltage and capacitance-magnetic field dependences. The results suggest potential use of this system as voltage-driven or magnetic field-driven non-volatile memory devices.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Chemistry, Multidisciplinary
Abdelali Khelfa, Jaysen Nelayah, Hakim Amara, Guillaume Wang, Christian Ricolleau, Damien Alloyeau
Summary: The understanding of temperature effects in nanochemistry requires real-time in situ measurements, as it influences both the kinetics of chemical reactions and the thermodynamic equilibrium of nanomaterials in solution. This study utilized temperature-controlled liquid cell transmission electron microscopy to directly image the radiolysis-driven formation of gold nanoparticles and provided insights into the atomic-scale processes influencing the size and shape of gold colloids. By comparing nucleation and growth rates with classical models, it was demonstrated that changes in temperature affect the formation dynamics of nanostructures in solution through increased molecular diffusion and gold solubility. Contrary to common belief, the dissolution and Ostwald ripening of nanoparticles are not solely driven by size effects, and visualizing thermal effects on faceting processes at the single nanoparticle level revealed the competition between growth speed and surface diffusion in determining the final shape of nanocrystals.
ADVANCED MATERIALS
(2021)
Article
Physics, Fluids & Plasmas
Marcell Tibor Mathe, Agnes Buka, Antal Jakli, Peter Salamon
Summary: A thermal gradient-induced circular motion of particles placed on ferroelectric nematic liquid crystal sessile drops is shown and explained in this study. The experiments demonstrate the unique properties of fluid ferroelectric liquid crystals, where the laminar flow drives the rotation of particles and gives them electric charge.
Article
Chemistry, Physical
Depanshu Varshney, Jai Prakash, Gautam Singh
Summary: This article investigates the alignment of liquid crystal (LC) molecules on the desired substrate using the noncontact-based technique. The study demonstrates the achievement of various alignment modes (homogeneous and homeotropic) by dispersing indium tin oxide (ITO) nanoparticles (0.25 wt% and 1 wt%) in an ITO sample cell without an alignment layer. The tunability in alignment is attributed to the interaction between ITO nanoparticles and their arrangements on the substrate.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Chemistry, Multidisciplinary
Pratibha Tripathi, Rahul Uttam, Sandeep Kumar, Roman Dabrowski, Ravindra Dhar
Summary: This study examines the thermodynamic, dielectric, and electro-optical properties of a room temperature nematic liquid crystal mixed with surface-stabilized gold nanoparticles. The results show that the addition of nanoparticles decreases the transition temperature of the liquid crystal and enhances its dielectric anisotropy. The study also identifies a relaxation mode in the dielectric behavior, caused by the flip-flop motion of the nematic molecules.
Article
Thermodynamics
Roi Meizoso Loureiro, Tania Carballeira Amarelo, Senen Paz Abuin, Ezequiel R. Soule, Roberto J. J. Williams
THERMOCHIMICA ACTA
(2015)
Article
Chemistry, Multidisciplinary
Ignacio Hegoburu, Ezequiel Rodolfo Soule
Article
Polymer Science
Agustin Santiago Andreu Artola, Ezequiel Rodolfo Soule
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS
(2018)
Article
Chemistry, Physical
Cristian Balbuena, Melisa M. Gianetti, Ezequiel R. Soule
JOURNAL OF CHEMICAL PHYSICS
(2018)
Article
Physics, Fluids & Plasmas
Sebastian Gurevich, Ezequiel Soule, Alejandro Rey, Linda Reven, Nikolas Provatas
Article
Chemistry, Physical
Cristian Balbuena, Melisa M. Gianetti, Ezequiel R. Soule
JOURNAL OF CHEMICAL PHYSICS
(2019)
Article
Physics, Condensed Matter
Cristian Balbuena, Ezequiel R. Soule
JOURNAL OF PHYSICS-CONDENSED MATTER
(2020)
Article
Chemistry, Physical
Ezequiel R. Soule
Summary: This study investigates the isomerization and phase behavior of azobenzenes using a theoretical model, and predicts that the presence of nematic ordering increases the rate of cis-to-trans isomerization. The study also analyzes the photo-induced phase transitions as a function of temperature and irradiation.
CHEMICAL PHYSICS LETTERS
(2022)
Article
Chemistry, Physical
Ezequiel R. Soule
Summary: This work extends the thermodynamically consistent theory for photoisomerization of azobenzenes to mixtures, taking into account different cases depending on the intrinsic capability of azobenzene and the second component to form ordered phases. Reentrant isotropic phases and a low temperature isotropic-nematic transition exist in mixtures, similar to pure azobenzenes, but the temperature range of each phase depends on the concentration. Phase diagrams with various coexistence regions and atypical shapes are found, including isotropic-isotropic, isotropic-nematic, and nematic-nematic transitions at different temperatures. The metastability of the nematic ordering under high irradiation intensity is also briefly discussed.
Article
Chemistry, Physical
Maria Victoria Uranga Wassermann, Ezequiel Rodolfo Soule, Cristian Balbuena
Summary: In this study, we used molecular dynamics simulations to investigate the influence of molecular morphological changes on the dynamic behavior of a trimer model. Our findings demonstrate that the molecular conformation significantly affects the relaxation times of the system, with systems possessing more linear conformations exhibiting longer relaxation times. Additionally, we observed that an increase in angular interaction rigidity leads to a deceleration in dynamics and an increase in dynamic heterogeneity. This study not only provides insights into azobenzene-type systems, but also lays the groundwork for further research on the microscopic details of related systems and potential extensions to composite systems.
Article
Chemistry, Physical
Cristian Balbuena, Melisa Mariel Gianetti, Ezequiel Rodolfo Soule
Summary: The relationship between structure and dynamical behavior in glassy materials is still an open issue, with the question of whether these dynamic phenomena have a thermodynamic origin remaining unanswered. Molecular dynamics simulations on a polymer glass-former reveal that structure does affect dynamic behavior, especially becoming more noticeable below the temperature where non-Arrhenius behavior is present and increasing as the system approaches the glass transition temperature. These findings suggest a connection between the structure and dynamics, potentially indicating the thermodynamic nature of glass transition.
Article
Chemistry, Physical
Cristian Balbuena, Melisa Mariel Gianetti, Ezequiel Rodolfo Soule
Summary: This study investigates the synthesis of silver nanoparticles with PVP as the capping agent through molecular dynamics simulations. It is found that the role of PVP in particle growth is mainly influenced by the competition between protective effect and bridging effect. The final structure and size of the particles are strongly dependent on the PVP content.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Physics, Fluids & Plasmas
Ezequiel Rodolfo Soule
Article
Physics, Fluids & Plasmas
Maria Virginia Zonta, Ezequiel Rodolfo Soule
Article
Chemistry, Physical
Safiya Allie, Ignacio Hegoburu, Min Jeong Shin, Jung Young Jung, Violeta Toader, Alejandro Rey, Ezequiel R. Soule, Linda Reven
Article
Chemistry, Physical
Yiping Yin, Zhe Wang, Hua Zou
Summary: This study presents a novel method for preparing dimpled polymer-silica nanocomposite particles using interfacial swelling-based seeded polymerization. The optimized conditions allow for a relatively high percentage of dimpled particles to be achieved.
Article
Chemistry, Physical
Brenden D. Hoehn, Elizabeth A. Kellstedt, Marc A. Hillmyer
Summary: Porous materials with nanometer-scale pores have important applications as nanoporous membranes. In this study, ABA triblock copolymers were used as precursors to produce nanoporous polymeric membranes (NPMs) in thin film form by degrading the end blocks. Polycyclooctene (PCOE) NPMs with tunable pore sizes were successfully prepared using solvent casting technique. Oxygen plasma etching was employed to improve the surface porosity and hydrophilicity of the membranes. This study provides a straightforward method to produce tough NPMs with high porosity and hydrophilic surface properties.
Article
Chemistry, Physical
Vladislav S. Petrovskii, Stepan I. Zholudev, Igor I. Potemkin
Summary: This article investigates the behavior of linear and ring polypeptide chains in aqueous solution and explores the properties of the complexes formed by these chains with oppositely charged surfactants. The results demonstrate that the complexes of linear supercharged unfolded polypeptides and the corresponding surfactants exhibit impressive adhesive properties.
Article
Chemistry, Physical
Merve Cevik, Serkan Dikici
Summary: Cardiovascular diseases are a leading cause of death globally, and vascular grafts are a promising treatment option. This study focuses on tissue-engineered vascular grafts (TEVGs) using decellularized parsley stems as a potential biomaterial. The decellularized parsley stems showed suitable properties for TEVGs, providing a suitable environment for human endothelial cells to form a pseudo endothelium. This study showcases the potential of using parsley stems for TEVGs.
Article
Chemistry, Physical
Gustavo A. Vasquez-Montoya, Tadej Emersic, Noe Atzin, Antonio Tavera-Vazquez, Ali Mozaffari, Rui Zhang, Orlando Guzman, Alexey Snezhko, Paul F. Nealey, Juan J. de Pablo
Summary: The optical properties of liquid crystals are typically controlled by electric fields. In this study, we investigate the effects of microfluidic flows and acoustic fields on the molecular orientation and optical response of nematic liquid crystals. We identify several previously unknown structures and explain them through calculations and simulations. These findings hold promise for the development of new systems combining sound, flow, and confinement.
Article
Chemistry, Physical
Xinjun Wu, Xin Guan, Shushu Chen, Jiangpeng Jia, Chongyi Chen, Jiawei Zhang, Chuanzhuang Zhao
Summary: This research presents a novel shape memory hydrogel with a remodelable permanent shape and programmable cold-induced shape recovery behavior. The hydrogel is prepared using specific treatment methods to achieve shape fixation by heating and shape recovery by cooling. Additionally, deformable devices can be obtained by assembling hydrogel blocks with different concentrations.
Article
Chemistry, Physical
Rebecca Hengsbach, Gerhard Fink, Ulrich Simon
Summary: This study examines the properties of DNA functionalized pNipmam microgels and pure pNipmam microgels at different concentrations of sodium chloride and in PBS solutions using temperature dependent H-1-NMR measurements. The results show that DNA modification affects the volume phase transition temperature and the addition of salt and PBS further enhances this effect.
Article
Chemistry, Physical
Ningyi Li, Junhong Li, Lijingting Qing, Shicheng Ma, Yao Li, Baohui Li
Summary: This paper investigates the self-assembly behavior of colloids with competing interactions under spherical confinement and finds that different ordered structures can be formed under different sized spherical confinements. Moreover, more perforated structures are formed in smaller spheres.
