We here develop a three-dimensional DMF (3D DMF) platform with patterned electrodes submerged in an oil medium to provide fundamental solutions to the technical limitations of 2D DMF platforms and water–air systems. 3D droplet manipulation on patterned electrodes is demonstrated by programmably controlling electrical signals. We also demonstrate the formation of precipitates on the 3D DMF platform through the reaction of different chemical samples. A droplet containing precipitates, hanging on the top electrode, can be manipulated without adhesion of precipitates to the solid surface. This method could be a good alternative strategy to alleviate the existing problems of 2D DMF systems such as cross-contamination and solute adsorption. In addition, we ascertain the feasibility of temperature-controlled chemical reaction on the 3D DMF platform by introducing a simple heating process. To demonstrate applicability of the 3D DMF system to 3D biological process, we examine the 3D manipulation of droplets containing mouse fibroblasts in the 3D DMF platform. Finally, we show detachment of droplets wrapped by a flexible thin film by adopting the electro-elasto-capillarity (EEC). The employment of the EEC may offer a strong potential in the development of 3D DMF platforms for drug encapsulation and actuation of microelectromechanical devices.

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Utilizing the advantages of a liquid metal (LM) (i.e., mercury) and its electro‐mechanical properties (i.e., high density, high surface tension, and high electrical conductivity), a novel capacitive‐type two‐axis accelerometer is proposed. The device employs a liquid‐type proof mass (i.e., liquid metal droplet) and is located in a cone‐shaped guiding channel. The Laplace pressure induced by the guiding channel and the LM droplet in the device acts as a spring due to the high surface tension of LM. To accurately set the spring constant of the device, a 2D mathematical model is established. Based on this mathematical model, the influence of the channel shape on device sensitivity is analyzed. Despite measuring the two‐axis accelerations using a single proof mass, the accelerometer yields a cross‐axis sensitivity of less than 1% for the x‐ and y‐axes. The accelerometer demonstrates an output similar to that of a reference accelerometer for a randomly applied acceleration. Owing to the nature of the liquid‐type proof mass, even if it is destroyed, its functionality is recovered by simply shaking the accelerometer. Finally, a 1.4% change in the accelerometer output is observed in the 15 000‐cycle test, and the device is applied to a maze escape game for verification.

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