Session: Research Posters

Paper Number: 165240

Magnetorheological Actuator Based on Carbonyl Iron Particles for Mechanical Characterization of Hydrogels 

The characterization of soft gels and tissues plays a vital role in various fields, including biomedical engineering, materials science, tissue engineering, and clinical applications. Investigating their mechanical properties is fundamental to the development of medical devices, therapeutic strategies, skin care products, and biomimetic materials that interact with biological tissues. However, despite significant progress, accurately characterizing hydrogels and soft biological tissues remains a challenging task. The existing methods for this task including rheology, atomic force microscopy (AFM), osmotic compression, micropipette aspiration, and capillary micromechanics are currently expensive, slow, sometimes require prolonged fabrication duration, and consume large amounts of hydrogel samples. In this work, we propose a magnetically controlled actuating device based on magnetorheological elastomer (MRE) to measure the mechanical properties of soft polymers (hydrogels) in a safe manner. The actuator is made from a smart stimuli-responsive composite material, which is a combination of a two-part polymeric matrix (Ecoflex 00-30 A and B) and micro ferromagnetic particles thereby enabling active control over both the mechanical properties and actuating motions of the device through magnetic field manipulation. Consequently, the magneto-active composite actuator can dynamically adjust its viscoelastic properties, including stiffness and damping. We fabricate and magnetically characterize different configurations of MRE samples based on carbonyl iron microparticles (CIP) and Ecoflex 00-30 to determine the MRE actuator with the best features for our work. Scanning electron microscopy (SEM) and Vibrating Sample Magnetometry (VSM) were performed for the isotropic and anisotropic MRE composites to study the material morphology, particle distribution, and magnetic behavior. Using the commercial finite element software COMSOL Multiphysics and the mechanical properties of isotropic MREs based on iron nanoparticles from previous work, we simulated the stiffness of the prepared MRE to be 25.3 N/m. Moreover, we can control the stiffness of the MRE by adjusting the magnetic particle weight or volume fraction, particle size, orientation, and the strength of the applied magnetic field. Information about the stiffness of the MREs serves as a reference for preparing and characterizing hydrogels with Young’s modulus compatible with the MRE for optimal performance since the properties of hydrogels are highly tunable. The magnetoresistive and magnetostrictive nature of MREs are used to enable accurate sensing and investigation of hydrogel normal and shear stresses. This facile method offers significant benefits compared to traditional wafer-based technologies and microfluidics, such as enhanced flexibility and stretchability, making it well-suited for complex environments. Overall, the proposed magneto-controllable device offers several advantages, including cost-effectiveness, fast actuation, ease of fabrication, minimal sample consumption, biocompatibility, and scalability, making it a promising candidate for diverse applications. Moreover, the incorporation of MREs reduces mechanical vibrations, further expanding its potential use across various fields compared to conventional actuators.

Presenting Author: Solomon Apuu King Abdullah University of Science and Technology (KAUST)

Presenting Author Biography: Solomon Apuu is currently pursuing a PhD degree in Mechanical Engineering at King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia. He is an ASME student member. His research interests include MEMS, polymer composites characterization, soft magnetic sensors, and actuators.

Authors:

Solomon Apuu King Abdullah University of Science and Technology (KAUST)
Mohannad Jabrah King Abdullah University of Science and Technology
Dana Al Sulaiman King Abdullah University of Science and Technology
Nouha Alcheikh Khalifa University of Science and Technology
Tadd Truscott King Abdullah University of Science and Technology (KAUST)