laser-micromachining-for-polymer-surface-topography-design

Laser Micromachining for Polymer Surface Topography Design

Soft magnetoactive elastomers (MAEs) are smart materials that respond to external magnetic fields by dynamically altering their mechanical properties. ...

Ostbayerische Technische Hochschule Regensburg

Stimuli responsive materials are key ingredients for any application that requires dynamically tunable or on-demand responses. In this work we report experimental and theoretical investigation of magnetic-field driven modifications of soft-magnetic elastomers whose surface was processed by laser ablation into lamellar microstructures that can be manipulated by a uniform magnetic field. We present a minimal hybrid model that elucidates the associated deflection process of the lamellae and explains the lamellar structure frustration in terms of dipolar magnetic forces arising from the neighbouring lamellae. We experimentally determine the magnitude of the deflection as a function of magnetic flux density and explore the dynamic response of lamellae to fast changes in a magnetic field. A relationship between the deflection of lamellae and modifications of the optical reflectance of the lamellar structures is resolved.

Dynamically tunable lamellar surface structures from magnetoactive elastomers driven by a uniform magnetic field.

It has been recently demonstrated that laser micromachining of magnetoactive elastomers is a very convenient method for fabricating dynamic surface microstructures with magnetically tunable properties, such as wettability and surface reflectivity. In this study, we investigate the impact of the micromachining process on the fabricated material's structural properties and its chemical composition. By employing scanning electron microscopy, we investigate changes in size distribution and spatial arrangement of carbonyl iron microparticles dispersed in the polydimethylsiloxane (PDMS) matrix as a function of laser irradiation. Based on the images obtained by a low vacuum secondary electron detector, we analyze modifications of the surface topography. The results show that most profound modifications occur during the low-exposure (8 J/cm) treatment of the surface with the laser beam. Our findings provide important insights for developing theoretical models of functional properties of laser-sculptured microstructures from magnetoactive elastomers.

Surface Modification of Magnetoactive Elastomers by Laser Micromachining.

The presence of a wetting ridge is crucial for many wetting phenomena on soft substrates. Conventional experimental observations of a wetting ridge require permanent presence of a droplet. The magnetic field-induced plasticity effect (FIPE) of soft magnetoative elastomers (MAEs) allows one to overcome this limitation. Depositing a droplet onto an MAE surface and applying a magnetic field fixes the wetting ridge in place due to the FIPE. The droplet can be removed to investigate the ridge with ease using conventional optical methods.

Article	Year
Dynamically tunable lamellar surface structures from magnetoactive elastomers driven by a uniform magnetic field. Soft matter\| PubMed ID: 37097616	2023
Surface Modification of Magnetoactive Elastomers by Laser Micromachining. Materials (Basel, Switzerland)\| PubMed ID: 38612065	2024
Preservation of wetting ridges using field-induced plasticity of magnetoactive elastomers. Journal of colloid and interface science\| PubMed ID: 39721074	2025

Raphael Kriegl

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