@article{KravanjaKrieglHribaretal., author = {Kravanja, Gaia and Kriegl, Raphael and Hribar, Luka and Glavan, Gašper and Drevenšek-Olenik, Irena and Shamonin (Chamonine), Mikhail and Jezeršek, Matija}, title = {Magnetically Actuated Surface Microstructures for Efficient Transport and Tunable Separation of Droplets and Solids}, series = {Advanced Engineering Materials}, volume = {25}, journal = {Advanced Engineering Materials}, number = {22}, publisher = {Wiley-VCH}, issn = {1527-2648}, doi = {10.1002/adem.202301000}, pages = {1 -- 11}, abstract = {Efficient transportation of droplets (∽10 ¹ ̶̶̶̶ 10 ² µl) and small solid objects (∽10 ¹ ̶ 10 ² mm ³ ) have important applications in many fields, such as microfluidics, lab-on-a-chip devices, drug delivery, etc. A novel multifunctional surface consisting of a periodic array of micro-lamellae from a soft magnetoactive elastomer (MAE) on a plastic substrate is reported for these purposes. The physical origin of the propulsion is the bending of soft magnetic lamellae in non-uniform magnetic fields, which is also observed in uniform magnetic fields. The magnetoactive surface is fabricated using a facile and rapid method of laser ablation. The propulsion of items is realized using a four-pole rotating magnet. This results in a cyclic lamellar fringe motion over the micro-structured surface and brings an advantage of easy reciprocation of transport by rotation reversal. Two modes of object transportation are identified: "pushing" mode for precise control of droplet and solid positioning and "bouncing" mode for heavier solid objects transportation. A water droplet of 5 μl or a glass sphere with a 2.1 mm diameter can be moved at a maximum speed of 60 mm s ⁻¹ . The multifunctionality of the proposed mechatronic platform is demonstrated on the examples of selective solid-liquid separation and droplet merging.}, language = {en} } @article{GlavanBelyaevaDrevenšek‐Oleniketal., author = {Glavan, Gašper and Belyaeva, Inna A. and Drevenšek-Olenik, Irena and Shamonin (Chamonine), Mikhail}, title = {Experimental study of longitudinal, transverse and volume strains of magnetoactive elastomeric cylinders in uniform magnetic fields}, series = {Journal of Magnetism and Magnetic Materials}, volume = {579}, journal = {Journal of Magnetism and Magnetic Materials}, publisher = {Elsevier}, issn = {0304-8853}, doi = {10.1016/j.jmmm.2023.170826}, abstract = {Magnetoactive elastomers (MAEs) are promising materials for realization of magnetic field-controlled soft actuators. Herein, a systematic investigation of magnetic field-induced macroscopic deformations of soft MAE cylinders with a diameter of 15 mm in uniform quasi-static magnetic fields directed parallel to the cylinder's axis is reported. The measurements were based on image processing. Thirty-six MAE samples differing in the weight fraction of the iron filler (70 wt\%, 75 wt\% and 80 wt\%), alignment of filling particles, and the aspect ratio (0.2, 0.4, 0.6, 0.8, 1.0 and 1.2) were fabricated. MAE cylinders exhibited high relative change in height (up to 35\% in the field of 485 kA/m) and lateral contraction. The dependence of the maximum extensional strain on the aspect ratio was obtained and compared with theoretical considerations. A concave dent was formed on the free circular base in magnetic fields. This concavity was characterized experimentally. A significant volumetric strain of the order of magnitude of 10\% was calculated in MAEs for the first time. In consequently repeated magnetization cycles, the remanent extensional strain significantly increased after each cycle. The results are qualitatively discussed in the framework of the modern views on the magnetically induced macroscopic deformations of MAEs. The directions of further research are outlined.}, language = {en} }