News

Uroš Tkalec from the Department of Condensed Matter Physics at the Jožef Stefan Institute and Simon Čopar from the Faculty of Mathematics and Physics at the University of Ljubljana have published a commentary entitled “Weaving braids of defect lines” in Nature Materials. The contribution, featured in the News & Views section, highlights advances in the programmable braiding of topological defects in liquid crystals.

In the study discussed, Chenhui Peng and colleagues used light and colloidal particles to create networks of braided defect lines in a nematic liquid crystal. The orientational structure of the liquid crystal around these lines carries information described in terms of so-called nematic bits. Much like braiding hair, the outcome of successive crossings depends on their order, a hallmark of non-Abelian operations. Moving the particles allows the sequence of operations to be rearranged and the network to be reprogrammed, while changes in the braiding can be observed directly under a microscope. The authors of the commentary highlight the transition from creating individual knots and links to designing networks that implement prescribed transformations of nematic bits. This approach connects soft-matter physics with topological information processing in a classical system at room temperature and builds in part on work by Slovenian researchers published in Science in 2011.… Read the rest “News & Views in Nature Materials”

Anja Pogačnik Krajnc, Matjaž Malok, and Maja Remškar in collaboration with Marjetka Conradi from Institute of Metals and Technology, Ljubljana, and Melita Tramšek and Marko Jeran from Department of Inorganic Chemistry and Technology K1 have published  an article entitled »Selective real-time monitoring of respiratory droplets for indoor air safety in educational environments« in »Building and Environment«.

Infectious respiratory diseases in kindergartens and schools spread primarily through tiny droplets of saliva that are exhaled or coughed out. Using the AeroDrops respiratory droplet detector—developed at the Jožef Stefan Institute (IJS)—we measured the concentration of respiratory droplets in real time within a kindergarten, a primary school classroom, a university lecture hall, and an experimental chemistry laboratory. The detector selectively counted respiratory droplets while remaining insensitive to other particles that constitute the majority of aerosols. Temporal variations in droplet concentrations reflected the impact of participant activities, occupancy levels, vocalization, and movement. The results demonstrate that the real-time, selective monitoring of respiratory droplets offers a novel approach for assessing indoor air quality and enables ventilation management that responds to actual exposure to potential infection.

Link to the article: https://doi.org/10.1016/j.buildenv.2026.115281
 

Our latest research, published in Polymers, demonstrates how extremely small amounts of two-dimensional MXene nanosheets can significantly improve the mechanical flexibility and piezoelectric performance of polymer films, opening new possibilities for flexible sensors, wearable electronics, and energy-harvesting devices.

In this study we investigated the incorporation of Ti₃C₂Tₓ MXene nanosheets into poly(vinylidene fluoride-co-trifluoroethylene) films prepared by solvent casting and thermal treatment. We demonstrated that interactions between MXene surfaces and polymer chains promote preferential molecular alignment and anisotropic crystallisation of the polymers’ electroactive β-phase, which is essential for efficient conversion of mechanical deformation into electrical signals.

Remarkably, an optimised MXene concentration of only 0.0015 wt% resulted in substantially improved mechanical deformability, increasing the elongation at break from approximately 60% for pristine polymer films to 192% for the nanocomposite. The films also exhibited enhanced dielectric properties (permittivity of 22) and a piezoelectric coefficient d₃₃ reaching 24 pC/N after 50% tensile elongation, while maintaining structural integrity.

Publication: V. Kokol, B. Nečemer, E. Gibertini, and V. Bobnar, Polymers 2026, 18, 2488.

Read the full article: https://doi.org/10.3390/polym18202488

On 9 October 2026, the University of Ljubljana presented the Dr Uroš Seljak Awards and Commendations for the fifth time, recognising outstanding scientific papers authored by undergraduate and master’s students in Slovenia.

Among this year’s award recipients is Sara Klopčič from the Solid State Physics Department at the Jožef Stefan Institute. She received the award for her scientific paper entitled “Electrically and Geometrically Tunable Photon Pair Entanglement from Ferroelectric Nematic Liquid Crystal.”

Her supervisor, Associate Professor Matjaž Humar from the Department of Solid State Physics at the Jožef Stefan Institute and the Faculty of Mathematics and Physics, University of Ljubljana, also received a plaque in recognition of his contribution to mentorship.

The Dr Uroš Seljak Award encourages students to engage in scientific research during their studies and highlights the importance of high-quality mentorship in achieving outstanding research results.

Marta Lavrič je v sodelovanju s skupino z odseka za kompleksne snovi F7 (A. Sterle, P. Medle Rupnik, L. Cmok, A. Erkoreka, N. Osterman, A. Mertelj, N. Sebastián) ter skupinami z Univerze iz Leedsa (C. J. Gibb, J. Hobbs, R. J. Mandle) in Univerze v Baskiji (A. Erkoreka, J. Martinez-Perdiguero) objavila članek z naslovom »Elasticity-Driven Periodic Polarization Patterns in a Chiral Ferroelectric Nematic Fluid (Z elastičnostjo vodeni periodični polarizacijski vzorci v kiralnem feroelektričnem nematskem fluidu)« v reviji Advanced Materials.

Medsebojna igra kiralnosti, omejenosti in elastičnosti lahko povzroči spontano nastajanje kompleksnih polarizacijskih vzorcev v kiralnih feroelektričnih nematskih tekočih kristalih. Ti trije dejavniki skupaj delujejo pri pretvorbi začetnega homogenega stanja v različne urejene strukture.

V novi študiji raziskovalci pokažejo, da se v omejenem prostoru ob odstopanju kiralne periode materiala od njegove naravne periode pojavijo periodične nestabilnosti, ko se material približuje helikoničnemu polarnemu stanju. V bližini tega prehoda se upogibna elastična konstanta tekočega kristala zmehča. Kombinacija preferirane vijačne strukture materiala, omejevanja in zmanjšanega upora proti upogibanju spodbuja nastanek periodičnih polarizacijskih vzorcev.

V omejenem prostoru te nestabilnosti vodijo do nastanka različnih samoorganiziranih struktur, vključno s progami, kvadratnimi in heksagonalnimi vzorci. S spreminjanjem debeline materiala v omejenem prostoru in površinske orientacije lahko raziskovalci nadzorujejo, katere strukture se pojavijo.… Read the rest “Članek v reviji Advanced Materials: Elasticity-Driven Periodic Polarization Patterns in a Chiral Ferroelectric Nematic Fluid”