Liquid metals are of great importance in developing wearable devices and soft robotics owing to its high conductivity and flexibility. However, the high density of such metals turned out to be big concern for many practical situations. With generalized purpose, a new conceptual material as lightweight liquid metal entity, which can be as light as water, is proposed here. For illustration, an unconventionally ultralight material composed of eutectic galliumindium alloys (eGaIn) and glass bubbles is demonstrated, whose density can be reduced below 2.010 even 0.448 g cm^‐3, even lighter than water, but still maintains excellent conformability, electric conductivity, and stiffness variety under temperature regulation. Such material is further adopted to build various complicated structures through origami or force regulation, representing various application scenarios and can be reused for eight times without evident loss in function. Based on these tests, buoyancy component for water‐related devices is designed, which offers the functions of a switch and loading element. The lightweight liquid metal entities are promising for making diverse advanced soft robotics and underwater devices in the near future.

中文翻译：

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轻质液态金属实体

液态金属由于其高导电性和柔韧性而在开发可穿戴设备和软机器人方面非常重要。然而，事实证明，这种金属的高密度是许多实际情况的主要问题。出于一般目的，在此提出了一种新的概念材料，如轻质液态金属实体，它可以像水一样轻。为了说明，展示了一种由共晶镓铟合金（eGaIn）和玻璃泡组成的非常规超轻材料，其密度甚至可以降低到2.010甚至0.448 g cm ^-3，甚至比水轻，但在温度调节下仍保持出色的顺应性，导电性和刚度变化。这种材料还被用来通过折纸或力调节来构建各种复杂的结构，代表各种应用场景，并且可以重复使用八次而不会明显丧失功能。基于这些测试，设计了用于水相关设备的浮力组件，该组件具有开关和负载元件的功能。轻质的液态金属实体有望在不久的将来制造出各种先进的软机器人和水下设备。