Hybrid magnetoactive soft elastomers: material development toward application in diaphragm pumps

Magnetoactive soft elastomers (MSEs) are widely studied for various applications, including soft robotics, biomedical devices, and diaphragm pumps. MSE composite materials typically consist of soft ferro- or ferrimagnetic particles embedded in a polymeric matrix, while a combination of both in MSEs is unexplored. In this study, magnetoactive soft membranes comprising thermoplastic elastomer and both types of magnetic fillers (hybrid filler), namely ferromagnetic carbonyl iron particles (CIP) and ferrimagnetic manganese ferrite (MnFe₂O₄) are developed. Their magnetoactive performance and thermal heating of the membranes are investigated. The magnetoactive displacement (s) of the MSE membrane with pure CIP are up to four times higher under a magnetic field of 38 mT than that of the one with MnFe₂O₄ particles. Applying an electromagnetic pulse, the response time (τ) of the membrane deformation is faster, and the temperature rise (ΔT) is higher for the MSE with MnFe₂O₄ particles. A figure of merit is proposed, comprising parameters, s and ΔT, to identify the optimum filler composition for a membrane pump. The MSE membrane with a hybrid CIP:MnFe₂O₄ filler ratio of 1:1 has emerged as a promising candidate for use in biomedical diaphragm pumps. Such pumps could transport and heat fluid simultaneously, and thereby, can be used to prevent issues like accidental hypothermia.