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Chen et al. Soft Sci. 2026, 6, 9 Page 5 of 36

Figure 2. Mechanical methods for preparation of MLMs. (A) Stirring process for EGaIn and Ni powder [52] . Reprinted with permission.
Copyright 2018, John Wiley and Sons; (B) Grinding-prepared MLMs with different Ni contents [46] . Reprinted with permission. Copyright
2019, John Wiley and Sons; (C) Stirring and sonication process for Ni-Mn-In particles and Galinstan [63] . Reprinted with permission.
Copyright 2025, Springer Nature; (D) Coating of ferronickel and polyethylene particles onto Galinstan through rolling [73] . Reprinted with
permission. Copyright 2019, John Wiley and Sons. MLMs: Magnetic liquid metals; FN: ferronickel; PE: polyethylene.

absence of complex chemical reactions or precursors. A key feature of the mechanical method is the
continuous disruption of the naturally formed oxide layer on the LM surface [52,64-67] . Upon rupture, fresh LM
is exposed and rapidly re-oxidized, forming new oxide layers with adhesive properties . These newly
[64]
formed oxides adhere to and coat magnetic particles during the mixing process, facilitating their
incorporation into the liquid matrix. This method is versatile, allowing for the integration of various particles
ranging from micro- to nanoscale into different LMs, such as Ga and EGaIn.

For example, researchers incorporated NdFeB microparticles into EGaIn through mechanical stirring and
confirmed the physical mixing without alloying via X-ray analysis . Similarly, a sticky Ni-LM ink for paper
[61]
electronics was fabricated by directly mixing Ni micropowders with EGaIn and highlighted the adhesion
enhancement effect of the oxide film wrapped Ni powders [Figure 2A] . In addition to stirring, the strong
[52]
shear forces from grinding can decrease the size of particles and promote the contact between the LMs and
particles [46,68,69] . Our group has reported the grounding of Ni particles together with EGaIn in a mortar, and
the EGaIn-Ni composite containing up to 80 wt% nickel can be prepared [Figure 2B] . As a powerful
[46]
supplementary method, sonication ensures homodisperse distribution of magnetic particles [Figure 2C] ,
[63]
enables the efficient production of MLM nano/microparticles from bulk MLMs , and facilitates composite
[70]
formation . Besides embedding magnetic particles into the LMs, the particles can also be arranged on the
[71]
surface of LMs [62,72,73] . For example, when rolling the Galinstan droplet on Fe particles, the particles can be
attached to the viscous oxidized surface of Galinstan, forming the MLM marbles [62] . In addition,
NaOH-treated Galinstan droplets could form spherical magnetic LM marbles upon rolling in a uniform
mixture of microscale ferronickel and polyethylene particles [Figure 2D] .
[73]