TY - JOUR A1 - Nadzharyan, Timur A. A1 - Shamonin (Chamonine), Mikhail A1 - Kramarenko, Elena Yu T1 - Theoretical Modeling of Magnetoactive Elastomers on Different Scales: A State-of-the-Art Review JF - Polymers N2 - A review of the latest theoretical advances in the description of magnetomechanical effects and phenomena observed in magnetoactive elastomers (MAEs), i.e., polymer networks filled with magnetic micro- and/or nanoparticles, under the action of external magnetic fields is presented. Theoretical modeling of magnetomechanical coupling is considered on various spatial scales: from the behavior of individual magnetic particles constrained in an elastic medium to the mechanical properties of an MAE sample as a whole. It is demonstrated how theoretical models enable qualitative and quantitative interpretation of experimental results. The limitations and challenges of current approaches are discussed and some information about the most promising lines of research in this area is provided. The review is aimed at specialists involved in the study of not only the magnetomechanical properties of MAEs, but also a wide range of other physical phenomena occurring in magnetic polymer composites in external magnetic fields. KW - magnetodeformation KW - magnetorheological effect KW - mechanical properties KW - magnetic particles KW - theoretical modeling KW - magnetorheological elastomersn KW - magnetoactive elastomers Y1 - 2022 U6 - https://doi.org/10.3390/polym14194096 VL - 14 IS - 19 SP - 1 EP - 42 PB - MDPI ER - TY - JOUR A1 - Kovalev, Alexander A1 - Belyaeva, Inna A. A1 - von Hofen, Christian A1 - Gorb, Stanislav A1 - Shamonin (Chamonine), Mikhail T1 - Magnetically Switchable Adhesion and Friction of Soft Magnetoactive Elastomers JF - Advanced Engineering Materials N2 - Herein, the effect of an applied moderate (~240 mT) magnetic field on the work of adhesion (WoA) of mechanically soft (the shear modulus ~10 kPa) magnetoactive elastomer (MAE) samples with two different mass fractions (70 and 80 wt%) of carbonyl iron powder (CIP) is concerned. The unfilled elastomer sample is used for comparison. Due to some sedimentation of filling particles, the concentration of inclusions in thin (~10 μm) subsurface layers is different. It is shown that the WoA increases (up to 1.8-fold) on the particle-enriched side (PES) in the magnetic field and its value is higher for higher filler concentration. On the particle-depleted side (PDS), WoA does not depend on particle concentration and on the magnetic field. Adhesion and friction are coupled in MAEs. No statistically significant difference in the friction coefficient, determined from the extended Amontons´ law, depending on sample side, CIP concentration, or presence of magnetic field is found. However, the PDS in the magnetic field demonstrates significantly higher critical shear stress compared to that for the PES or PDS in the absence of magnetic field. Correlations between different surface properties are discussed. Obtained results are useful for the development of magnetically controllable soft robots. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-45283 N1 - Corresponding authors: Stanislav Gorb und Mikhail Shamonin VL - 24 IS - 10 SP - 1 EP - 8 PB - WILEY-VCH ER - TY - CHAP A1 - Kravanja, Gaia A1 - Belyaeva, Inna A. A1 - Hribar, Luka A1 - Drevenšek‐Olenik, Irena A1 - Shamonin (Chamonine), Mikhail A1 - Jezeršek, Matija T1 - Adaptive Magneto-Responsive Surfaces Fabricated by Laser-Based Microstructuring T2 - Proceedings of the ASME 2022 Conference on Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS 2022): September 12-14, 2022, Dearborn, Michigan N2 - Adaptive surface microstructures are used extensively in nature to control various surface properties such as wettability, adhesion, self-cleaning, drag reduction, etc. Regulation of these properties can be achieved with the appropriate employment of a multitude of smart materials, whose characteristics/response can be controlled by noncontact stimuli, e.g., light, heat, or magnetic field. One of the very promising magneto-regulable smart materials are magnetoactive elastomers (MAEs). They are comprised of a compliant polymer matrix with embedded micrometer-sized ferromagnetic particles. The particles interact with each other and a magnetic field. This results in remarkable tunability of the physical properties of MAEs. This paper reports a fast, resilient, and tailored method for direct surface micromachining of MAEs that enables micro-structuring without mechanical contact between the tool and the material, bypassing the usual constraints of conventional fabrication methods. It is shown that it is possible to fabricate a large variety of different microstructure geometries whose precision is limited predominantly by the size of magnetic particles. Lamellar structures with a high aspect ratio (up to 6:1) oriented either perpendicularly to the surface, can be strongly bent by applying magnetic fields in the range of 0–250 mT. KW - adaptive surfaces KW - magnetoactive elastomers KW - magneto-responsive microstructures KW - laser microstructuring Y1 - 2022 SN - 978-0-7918-8627-4 U6 - https://doi.org/10.1115/SMASIS2022-90742 PB - ASME ER - TY - JOUR A1 - Kriegl, Raphael A1 - Kravanja, Gaia A1 - Hribar, Luka A1 - Čoga, Lucija A1 - Drevenšek‐Olenik, Irena A1 - Jezeršek, Matija A1 - Kalin, Mitjan A1 - Shamonin (Chamonine), Mikhail T1 - Microstructured Magnetoactive Elastomers for Switchable Wettability JF - Polymers N2 - We demonstrate the control of wettability of non-structured and microstructured magnetoactive elastomers (MAEs) by magnetic field. The synthesized composite materials have a concentration of carbonyl iron particles of 75 wt.% (≈27 vol.%) and three different stiffnesses of the elastomer matrix. A new method of fabrication of MAE coatings on plastic substrates is presented, which allows one to enhance the response of the apparent contact angle to the magnetic field by exposing the particle-enriched side of MAEs to water. A magnetic field is not applied during crosslinking. The highest variation of the contact angle from (113 ± 1)° in zero field up to (156 ± 2)° at about 400 mT is achieved in the MAE sample with the softest matrix. Several lamellar and pillared MAE structures are fabricated by laser micromachining. The lateral dimension of surface structures is about 50 µm and the depth varies between 3 µm and 60 µm. A systematic investigation of the effects of parameters of laser processing (laser power and the number of passages of the laser beam) on the wetting behavior of these structures in the absence and presence of a magnetic field is performed. In particular, strong anisotropy of the wetting behavior of lamellar structures is observed. The results are qualitatively discussed in the framework of the Wenzel and Cassie-Baxter models. Finally, directions of further research on magnetically controlled wettability of microstructured MAE surfaces are outlined. The obtained results may be useful for the development of magnetically controlled smart surfaces for droplet-based microfluidics. Y1 - 2022 U6 - https://doi.org/10.3390/polym14183883 N1 - Corresponding authors: Raphael Kriegl und Mikhail Shamonin VL - 14 IS - 18 SP - 1 EP - 21 PB - MDPI ER - TY - JOUR A1 - Savelev, Dmitrii V. A1 - Glavan, Gašper A1 - Belan, Viktoria O. A1 - Belyaeva, Inna A. A1 - Fetisov, Leonid Y. A1 - Shamonin (Chamonine), Mikhail T1 - Resonant Magnetoelectric Effect at Low Frequencies in Layered Polymeric Cantilevers Containing a Magnetoactive Elastomer JF - Applied Sciences N2 - In this work, the resonance enhancement of magnetoelectric (ME) coupling at the two lowest bending resonance frequencies was investigated in layered cantilever structures comprising a magnetoactive elastomer (MAE) slab and a commercially available piezoelectric polymer multilayer. A cantilever was fixed at one end in the horizontal plane and the magnetic field was applied horizontally. Five composite structures, each containing an MAE layer of different thicknesses from 0.85 to 4 mm, were fabricated. The fundamental bending resonance frequency in the absence of a magnetic field varied between roughly 23 and 55 Hz. It decreased with the increasing thickness of the MAE layer, which was explained by a simple theory. The largest ME voltage coefficient of about 7.85 V/A was measured in a sample where the thickness of the MAE layer was ≈2 mm. A significant increase in the bending resonance frequencies in the applied DC magnetic field of 240 kA/m up to 200% was observed. The results were compared with alternative designs for layered multiferroic structures. Directions for future research were also discussed. KW - flexible composite KW - low frequency KW - magnetoactive elastomer KW - magnetoelectric effect KW - piezoelectric polymer Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-30637 N1 - corresponding authors: Dmitry V. Saveliev and Mikhail Shamonin VL - 12 IS - 4 SP - 1 EP - 13 PB - MPDI ER - TY - JOUR A1 - Dillinger, Andrea Elisabeth A1 - Weber, Gregor R. A1 - Mayer, Matthias A1 - Schneider, Magdalena A1 - Göppner, Corinna A1 - Ohlmann, Andreas A1 - Shamonin (Chamonine), Mikhail A1 - Monkman, Gareth J. A1 - Fuchshofer, Rudolf A1 - Keller, Kate A1 - Lozano, Diana C. A1 - Clark, Abbot T1 - CCN2/CTGF-A Modulator of the Optic Nerve Head Astrocyte JF - Frontiers in cell and developmental biology (Front Cell Dev Biol.) N2 - In primary open-angle glaucoma (POAG), a neurodegenerative disease of the optic nerve (ON) and leading cause of blindness, the optic nerve head (ONH) undergoes marked structural extracellular matrix (ECM) changes, which contribute to its permanent deformation and to degeneration of ON axons. The remodeling process of the ECM causes changes in the biomechanical properties of the ONH and the peripapillary sclera, which is accompanied by an increased reactivity of the resident astrocytes. The molecular factors involved in the remodeling process belong to the Transforming growth factor (TGF)-β superfamily, especially TGF-β2. In previous publications we showed that TGF-β2 induced ECM alterations are mediated by Cellular Communication Network Factor (CCN)2/Connective Tissue Growth Factor (CTGF) and recently we showed that CCN2/CTGF is expressed by astrocytes of the ON under normal conditions. In this study we wanted to get a better understanding of the function of CCN2/CTGF under normal and pathologic conditions. To this end, we analyzed the glial lamina and peripapillary sclera of CCN2/CTGF overexpressing mice and studied the effect of CCN2/CTGF and increasing substratum stiffness on murine ON astrocytes in vitro. We observed enhanced astrocyte reactivity in the ONH, increased ECM protein synthesis in the peripapillary sclera and increased Ccn2/Ctgf expression in the ONH during the pathologic development in situ. CCN2/CTGF treatment of primary murine ON astrocytes induced a higher migration rate, and increase of ECM proteins including fibronectin, elastin and collagen type III. Furthermore, the astrocytes responded to stiffer substratum with increased glial fibrillary acidic protein, vimentin, actin and CCN2/CTGF synthesis. Finally, we observed the reinforced appearance of CCN2/CTGF in the lamina cribrosa of glaucomatous patients. We conclude that reactive changes in ONH astrocytes, induced by the altered biomechanical characteristics of the region, give rise to a self-amplifying process that includes increased TGF-β2/CCN2/CTGF signaling and leads to the synthesis of ECM molecules and cytoskeleton proteins, a process that in turn augments the stiffness at the ONH. Such a scenario may finally result in a vicious circle in the pathogenesis of POAG. The transgenic CTGF-overexpressing mouse model might be an optimal model to study the chronic pathological POAG changes in the ONH. KW - astrocytes KW - extracellar matrix KW - glaucoma KW - glial lamina KW - growth factors KW - optic nerve KW - stiffness Y1 - 2022 U6 - https://doi.org/10.3389/fcell.2022.864433 VL - 10 PB - frontiers ER - TY - JOUR A1 - Glavan, Gašper A1 - Belyaeva, Inna A. A1 - Shamonin (Chamonine), Mikhail T1 - Multiferroic Cantilevers Containing a Magnetoactive Elastomer: Magnetoelectric Response to Low-Frequency Magnetic Fields of Triangular and Sinusoidal Waveform JF - Sensors N2 - In this work, multiferroic cantilevers comprise a layer of a magnetoactive elastomer (MAE) and a commercially available piezoelectric polymer-based vibration sensor. The structures are fixed at one end in the horizontal plane and the magnetic field is applied vertically. First, the magnetoelectric (ME) response to uniform, triangle-wave magnetic fields with five different slew rates is investigated experimentally. Time and field dependences of the generated voltage, electric charge, and observed mechanical deflection are obtained and compared for four different thicknesses of the MAE layer. The ME responses to triangular and sinusoidal wave excitations are examined in contrast. Second, the ME response at low frequencies (≤3 Hz) is studied by the standard method of harmonic magnetic field modulation. The highest ME coupling coefficient is observed in the bias magnetic field strength of ≈73 kA/m and it is estimated to be about 3.3 ns/m (ME voltage coefficient ≈ 25 V/A) at theoretically vanishing modulation frequency (f→0 Hz). Presented results demonstrate that the investigated heterostructures are promising for applications as magnetic-field sensors and energy harvesting devices. KW - magnetoactive elastomer KW - piezoelectric polymer KW - multilayer cantilever KW - direct magnetoelectric effect KW - magnetic field sensing Y1 - 2022 U6 - https://doi.org/10.3390/s22103791 N1 - Corresponding authors: Gašper Glavan und Mikhail Shamonin Veröffentlichtes Datenset: https://doi.org/10.5281/zenodo.14651784 VL - 22 IS - 10 SP - 1 EP - 17 PB - MDPI CY - Basel ER -