vodja laboratorija: red. prof. dr. Samo Kralj

člani laboratorija: red. prof. dr. Nataša Vaupotič, izr. prof. dr. Robert Repnik, izr. prof. dr. Mitja Slavinec,  doc. dr. Milan Ambrožič, doc. dr. Milan Svetec, doc. dr. Uroš Tkalec, dr. Eva Klemenčič, dr. Kaushik Pal, dr. Luka Mesarec, mag. Saša Harkai, mag. Dejvid Črešnar

Ambiciozni cilj fizike je modeliranje vseh opažanj v naravi. Ustrezno modeliranje omogoča kontrolo oziroma napovedovanje pojava, kar lahko večinoma preverimo eksperimentalno. V prvotnem obdobju so se fiziki osredotočali predvsem na ravnovesne pogoje in so se precej neuspešno spopadali z analitično nerešljivimi nelinernimi pojavi. Toda praktično vso obnašanje narave je nelinerno in praviloma daleč od ravnovesja (npr. človek je najbližje ravnovesju, ko umre). Posledično so bile fizikalne napovedi uspešne le za redke pojave v raznovrstni paleti naravnih dogodkov. Toda interval naravnih opažanj, pri razlagi katerih so fiziki uspešnih, se je začel dramatično širiti z razvojem računalništva. Dandanes fizika postopoma vstopa tudi na zanjo popolnoma netradicionalna področja, kot sta npr. sociologija in psihologija. Izkazalo se je, da kažejo raznovrstni pojavi, ki so navidez pogosto popolnoma različni, sorodno matematično (t.i. univerzalno) obnašanje. Slednje je tipična lastnost KOMPLEKSNIH SISTEMOV, ki predstavlja eno izmed modnih področij sodobne fizike.

Za kompleksne sisteme (KS) je značilno, da na njih vplivajo številni parametri, na katere se sistem odziva nelinearno. Njihovo obnašanje je v nekaterih primerih nepredvidljivo in izjemno raznovrstno. Slednji pogoji so med drugim bili ključni za nastanek življenja na Zemlji. Kot predstavnike kompleksnih sistemov omenimo mehke materiale, kompozitne materiale, različne biološke sisteme, civilizacije…, torej vsebujejo tako neživi kot živi svet. V njih igrajo pogosto ključno vlogo povezave med komponentami sistema, ki so lahko pomembnejše od vpliva detajlne strukture komponente. Slednji razlog je ključ do univerzalnega obnašanja, ki pogosto matematično povezuje povsem različne KS. Za primer omenimo teorijo samoorganizirane kritičnosti, ki uporablja sorodni matematični opis zapotresne aktivnosti, vulkanske izbruhe, borzne dogodke, populacijo mest, napovedovanja pogostosti izgovorjenih besed, možganske aktivnosti, izumiranje živih bitij ter civilizacij, itd…

Raziskovalno delo laboratorija

Člani laboratorija sodelujemo s številnimi uveljavljenimi skupinami doma in po svetu (Italija, Poljska, Romunija, Anglija, Rusija, Češka, Grčija, Francija, ZDA, Indija). Sodelujemo v številnih domačih in mednarodnih raziskovalnih projektih.

Trailer 2020

Double gyroid phase transforms into orthorombic phase due to a tendency to form helical pillars

J. Matraszek, D. Pociecha, N. Vaupotič, M. Salamonczyk, M. Vogrin, E. Górecka, Bi-continuous orthorhombic soft matter phase made of polycatenar molecules, Soft matter 26, 3882 (2020). pdf na 10.1039/d0sm00331j


Chiral flow states in pressure-driven nematic liquid crystal.

S. Čopar, Ž. Kos, T. Emeršič, U. Tkalec, Microfluidic control over topological states in channel-confined nematic flows. Nature Communications 11, 59 (2020). pdf


Rewiring of disclinations (Movies: experiment and simulations)

S. Harkai, B. Murray, C. Rosenblatt, S. Kralj, Electric field driven reconfigurable multistable topological defect patterns, Physical review research 2, 0131761 (2020). pdf


Illustrations of trapped adaptive spherical NPs within line defects.

A. Gudimalla, M. Lavrič, M. Trček, S. Harkai, B. Rožič, G. Cordoyiannis, S. Thomas, K. Pal, Z. Kutnjak, S. Kralj, Nanoparticle-stabilized lattices of topological defects in liquid crystals, International journal of thermophysics 41, 51 (2020). pdf


M. Lavrič, G. Cordoyiannis, V. Tzitzios, I. Lelidis, S. Kralj, G. Nounesis, S. Žumer, M. Daniel, Z. Kutnjak, Blue phase stabilization by CoPt-decorated reduced-graphene oxide nanosheets dispersed in a chiral liquid crystal, Journal of applied physics 127, 095101 (2020). pdf


Trailer 2019

Achiral liquid crystalline material behaves like a four layer chiral ferrielectric phase and tries to unwind when temperature reduces

M. Salamonczyk, N. Vaupotič, D. Pociecha, R. Walker, J. M. Storey, C. T. Imrie, C. Wang, C. Zhu, E. Górecka, Multi-level chirality in liquid crystals formed by achiral molecules. Nature communications 8, 1922 (2019). pdf na 10.1038/s41467-019-09862-y.


Sculpting flow-aligned nematic domains in microfluidic environment.

T. Emeršič, R. Zhang, Ž. Kos, S. Čopar, N. Osterman, J. J. de Pablo, U. Tkalec, Sculpting stable structures in pure liquids. Science Advances 5, eaav4283 (2019). pdf


Intrinsic curvature dominated order parameter profiles and equilibrium membrane shapes.

L. Mesarec, W. Góźdź, A. Iglič, V. Kralj-Iglič, E. Virga, S. Kralj, Normal red blood cells’ shape stabilized by membrane’s in-plane ordering, Scientific reports 9, 19742 (2019). pdf


Schematic representations of electro caloric effect based devices.

E. Klemenčič, M. Trček, Z. Kutnjak, S. Kralj, Giant electrocaloric response in smectic liquid crystals with direct smectic-isotropic transition, Scientific reports 9, 1721 (2019). pdf


Schematic representation of a catenoid surface.

P. Kurioz, L. Mesarec, A. Iglič, S. Kralj, Assembling of topological defects at neck-shaped membrane parts. Physica status solidi. A, Applications and materials science 216, 1800722 (2019). pdf


Geometry of spherocylinders in simulations.

M. Ambrožič, S. Kralj, Field percolation-switching in soft ternary anisotropic system, Physica. A, Statistical mechanics and its applications 520, 11 (2019). pdf


Spin configurations in different “horizontal” planes.

M. Ambrožič, S. Kralj, Thickness induced line-defect reconfigurations in thin nematic cell, Advances in condensed matter physics 2019, 1 (2019). pdf


Schematic presentation of paranematic clusters embedded in the isotropic fluid.

D. Črešnar, C. Kyrou, I. Lelidis, A. Drozd-Rzoska, S. Starzonek, S. J. Rzoska, Z. Kutnjak, S. Kralj, Impact of weak nanoparticle induced disorder on nematic ordering, Crystals 9, 171 (2019). pdf


Temperature dependencies of dielectric constant for 5CB and 5CB+BaTiO3 nanocolloids.

A. Drozd-Rzoska, S. Starzonek, S. Rzoska, S. Kralj, Nanoparticle-controlled glassy dynamics in nematogen-based nanocolloids, Physical review. E 99, 052703 (2019). pdf


Report on high-resolution calorimetry and small-angle X-ray scattering measurements along the Smectic-A to chiral Smectic-C* phase transition of the liquid crystal 4-(2-methyl butyl) phenyl 4-n-octylbiphenyl-4-carboxylate with dispersed, CoPt nanoparticle-coated reduced-graphene oxide nanosheets.

M. Lavrič, G. Cordoyiannis, V. Tzitzios, S. Kralj, G. Nounesis, I. Lelidis, H. Amenitsch, Z. Kutnjak, The effect of CoPt-coated reduced-graphene oxide nanosheets upon the Smectic-A to Smectic-C* phase transition of a chiral liquid crystal, Liquid crystals 7, 1 (2019). pdf


Planar cells of 5OO8+1% colloidal particles in the nematic phase.

C. Kyrou, D. Tsiourvas, S. Kralj, I. Lelidis, Effect of superhydrophobic nanoplatelets on the phase behaviour of liquid crystals, Journal of molecular liquids 298, 111984 (2019). pdf


Schematic representation of bent-core liquid crystal confined geometry in photo-refractive ITO-LC cell fabrication

S. I. Asiya, K. Pal, G. S. El-Sayyad, M. A. Elkodous, C. Demetriades, S. Kralj, S. Thomas, Reliable optoelectronic switchable device implementation by CdS nanowires conjugated bent-core liquid crystal matrix, Organic electronics 32,105592 (2019). pdf


Curvature induced topological defects.

E. Klemenčič, P. Kurioz, S. Kralj, R. Repnik, Topological defect enabled formation of nematic domains, Liquid crystals47, 618 (2019). pdf


Budding of an erythrocyte membrane.

M. Draba, L. Mesareca, R. Imanic, M. Jerana, I. Junkare, V. Kralj-Iglič, S. Kraljf, A. Iglič, The role of membrane vesiculation and encapsulation in cancer diagnosis and therapy,Advances in Biomembranes and Lipid Self-Assembly 29, 159 (2019). pdf


Trailer 2018

Twist-bend nematic phase forms modulated structure that effectively diffracts light and transforms its polarization properties

N. Vaupotič, M. Ali, P. Majewski, E. Górecka, D. Pociecha, Polarization gratings spontaneously formed from a helical twist-bend nematic phase. ChemPhysChem : a European journal of chemical physics and physical chemistry 19, 2566(2018). pdf na 10.1002/cphc.201800360.


Kaleidoscopic texture in patterned smectic A phase of 8CB liquid crystal.

D. S. Kim, S. Čopar, U. Tkalec, D. K. Yoon, Mosaics of topological defects in micropatterned liquid crystal textures. Science Advances 4, eaau8064 (2018). pdf


Curvature driven generation of defects.

L. Mesarec, A. Iglič, S. Kralj, Topological defect driven membrane fission, Advanced biomedical research and innovation1, 1, (2018). pdf


Schematic figure of an electrical double layer near a negatively charged surface, which mimics the LC–aqueous interface.

A. Dubtsov, S. Pasechnik, D. Shmeliova, A. Saidgaziev, E. Gongadze, A. Iglič, S. Kralj, Liquid crystalline droplets in aqueous environments: electrostatic effects, Soft matter 14, 9619 (2018). pdf


Structural transitions in a liquid crystal droplet.

A. Dubtsov, S. Pasechnik, D. Shmeliova, D. Semerenko, A. Iglič, S. Kralj, Influence of polar dopant on internal configuration of azoxybenzene nematic-in-water droplets, Liquid crystals 45, 388 (2018). pdf


Key stages of the electro caloric effect based cycle in which we subtract heat from a thermal reservoir.

M. Krašna, E. Klemenčič, Z. Kutnjak, S. Kralj, Phase-changing materials for thermal stabilization and thermal transport. Energy 162, 554 (2018). pdf


Typical scribed surface topography enforcing the m = 2 topological defect.

P. Kurioz, M. Kralj, B. Murray, C. Rosenblatt, S. Kralj, Nematic topological defects positionally controlled by geometry and external fields. Beilstein journal of nanotechnology9, 109 (2018). pdf


Experimental set-up for Raman Polarization Spectroscopy.

C. Kyrou, S. Kralj, M. Panagopoulou, Y. Raptis, G. Nounesis, I. Lelidis, Impact of spherical nanoparticles on the nematic order parameters, Phys. Rev. E 97, 042701 (2018). pdf


Trailer 2017

Resonant soft X-ray scattering unmasks the nanoscale helical structure in soft matter materials with no electron density modulation

M. Salamonczyk, N. Vaupotič, D. Pociecha, C. Wang, C. Zhu, E. Górecka, Structure of nanoscale-pitch helical phases: blue phase and twist-bend nematic phase resolved by resonant soft X-ray scattering. Soft matter 38, 6694 (2017). pdf na 10.1039/c7sm00967d.


Decomposition vs. Escape of Topological Defects in a Nematic Liquid Crystal.

B. Murray, S. Kralj, C. Rosenblatt, Decomposition vs. escape of topological defects in a nematic liquid crystal, Soft matter 13, 8442 (2017). pdf


The isothermal (T = 368 K) pressure evolution of dielectric constant in 5OCB and 5OCB + NPs (BaTiO3, superparaelectric cubic phase) systems.

S. Starzonek, S. Rzoska, A. Drozd-Rzoska, K. Czupryński, S. Kralj, Impact of ferroelectric and superparaelectric nanoparticles on phase transitions and dynamics in nematic liquid crystals, Physical review 96, 022705 (2017). pdf


S. Kralj, B. Murray, C. Rosenblatt, Decomposition of strongly charged topological defects, Physical review. E95, 042702 (2017). pdf


Twist-grain boundary phase stabilized by Au nanoparticles.

M. Trček, G. Cordoyiannis, B. Rožic, V. Tzitzios, G. Nounesis, S. Kralj, I. Lelidis, E. Lacaze, H. Amenitsch, Z. Kutnjak, Twist-grain boundary phase induced by Au nanoparticles in a chiral liquid crystal host, Liquid crystals 44, 1575 (2017). pdf


Impact of curvature on topological defects.

 L. Mesarec, W. Góźdź, A. Iglič, S. Kralj, Impact of curvature on topological defects, Journal of Physics: Conf. Series 780, 012015 (2017). pdf


Non-axisymmetric vesicle shape calculated by MC simulations for the membrane composed of two isotropic constituents.

L. Mesarec, W. Góźdź, S. Kralj, M. Fošnarič, S. Penič, V. Kralj-Iglič, A. Iglič, On the role of external force of actin filaments in the formation of tubular protrusions of closed membrane shapes with anisotropic membrane components, European biophysics journal 46, 705 (2017). pdf


Typical DLA networks used in our simulations.

S. Harkai, M. Ambrožič, S. Kralj, Impact of diffusion limited aggregates of impurities on nematic ordering, Physica. A 467, 249 (2017). pdf