Fabrication of Multiphase Liquid Metal Composites Containing Gas and Solid Fillers: From Pastes to Foams
Fabrication of Multiphase Liquid Metal Composites Containing Gas and Solid Fillers: From Pastes to Foams
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DOI：
10.1021/acsaenm.3c00092
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发表时间：
2023-05
期刊：
影响因子：
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通讯作者：
Shreyas Kanetkar;Najam-ul-Hassan Shah;Rohit M. Gandhi;Aastha Uppal;M. Dickey;Robert Y. Wang;K. Rykaczewski
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文献类型：
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作者：
Shreyas Kanetkar;Najam-ul-Hassan Shah;Rohit M. Gandhi;Aastha Uppal;M. Dickey;Robert Y. Wang;K. Rykaczewski
镓基液态金属（LM）由于其独特的金属和液体性质的组合，适合于许多潜在的应用。然而，由于它们的高表面张力和低粘度，LM具有挑战性地以有用的形状（例如点、线和膜）施加到基底。这些问题通过在空气中将LM与其他材料混合来缓解，例如与固体颗粒混合以形成LM固体糊剂或与气体混合以形成LM泡沫。在这些看似简单的混合过程背后，是复杂且高度交织的微观机制。在制造LM糊剂时，不可避免地掺入空气微泡，使其部分发泡。另一方面，为了使LM发泡，必须首先内化固体颗粒的临界体积含量。因此，LM浆料和泡沫都是含有固体和流体微组分的多相复合材料。在这里，我们系统地研究了混合过程，固体颗粒尺寸和体积分数（SiO2）的多相LM复合材料的空气含量的影响。我们证明，减小颗粒尺寸和增加它们的体积分数实质上降低了复合材料的密度（即，增加空气滞留）。发泡过程也可以通过使用高速机械混合来增强，尽管导致形成更无序的内部结构。相比之下，用较大的微粒手动混合可以促进具有最小空气含量的更糊状复合材料的形成。我们解释这些趋势的微观机制相关的宏观测量与横截面电子显微镜的内部结构。
Gallium-based liquid metals (LMs) are suitable for many potential applications due to their unique combination of metallic and liquid properties. However, due to their high surface tension and low viscosity, LMs are challenging to apply to substrates in useful shapes, such as dots, wires, and films. These issues are mitigated by mixing the LMs in air with other materials, such as mixing with solid particles to form LM solid pastes or mixing with gases to form LM foams. Underlying these deceivingly simple mixing processes are complex and highly intertwined microscale mechanisms. Air microbubbles are inevitably incorporated while making LM pastes, making them partly foams. On the other hand, for foaming of the LM to occur, a critical volume content of solid particles must be internalized first. Consequently, both LM pastes and foams are multiphase composites containing solid and fluid microcomponents. Here, we systematically study the impact of the mixing procedure, solid particle size, and volume fraction (SiO2) on the air content of the multiphase LM composites. We demonstrate that decreasing the particle size and increasing their volume fraction substantially decrease the composite density (i.e., increases air entrapment). The foaming process can also be enhanced with the use of high-speed mechanical mixing, although leading to the formation of a more disordered internal structure. In contrast, manual mixing with larger microparticles can promote the formation of more paste-like composites with minimal air content. We explain the microscopic mechanisms underlying these trends by correlating macroscopic measurements with cross-sectional electron microscopy of the internal structure.