Liquid Metal Droplets‐Based Elastomers from Electric Toothbrush‐Inspired Revolving Microfluidics

Abstract

Liquid metal (LM)‐based elastomers have a demonstrated value in flexible electronics. Attempts in this area include the development of multifunctional LM‐based elastomers with controllable morphology, superior mechanical performances, and great stability. Herein, inspired by the working principle of electric toothbrushes, a revolving microfluidic system is presented for the generation of LM droplets and construction of desired elastomers. The system involves revolving modules assembled by a needles array and 3D microfluidic channels. LM droplets can be generated with controllable size in a high‐throughput manner due to the revolving motion‐derived drag force. It is demonstrated that by employing a poly(dimethylsiloxane) (PDMS) matrix as the collection phase, the generated LM droplets can act as conductive fillers for the construction of flexible electronics directly. The resultant LM droplets‐based elastomers exhibit high mechanical strength, stable electrical performance, as well as superior self‐healing property benefiting from the dynamic exchangeable urea bond of the polymer matrix. Notably, due to the flexible programmable feature of the LM droplets embedded within the elastomers, various patterned LM droplets‐based elastomers can be easily achieved. These results indicate that the proposed microfluidic LM droplets‐based elastomers have a great potential for promoting the development of flexible electronics.

Free‐Boundary Microfluidic Platform for Advanced Materials Manufacturing and Applications

“…In this section, we focus on four types of FBMM, including hydrodynamics-based, interfacial tension-based, acoustics-based, and electrodynamics-based (Figure 2). The hydrodynamics-based FBMM includes the flow focusing, [50,58,60,[81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97] co-flow, [62,63, cross-flow, [61,[129][130][131][132][133][134][135][136][137][138][139] and free jet channel geometries. [56,[140][141][142][143][144][145][146] The interfacial tension-based FBMM includes single-axial, oblique, and spinning.…”

“…[56,[140][141][142][143][144][145][146] The interfacial tension-based FBMM includes single-axial, oblique, and spinning. [61,[129][130][131][132][133][134][135][136][137][138][139] The acoustics-based FBMM includes ejection, acoustophoretic, and vibrating. [48,55,[147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163][164][165] The electrodynamics-based FBMM includes electrospray, [51, electrohydrodynamic (EHD) inkjet printing, [53,165, and electrospinning.…”

Pressure-Activatable Liquid Metal Composites Flexible Sensor with Antifouling and Drag Reduction Functional Surface

“…For flexible sensors, it is important to focus not only on the packaging layer’s ability to withstand the external environment but also on the properties of the sensing layer. Additionally, the sensing layer should be biologically friendly to prevent environmental hazards in the case of sensor damage or leakage. − Liquid metal (LM) alloys, such as gallium and indium, have attracted attention in recent years due to their flexibility, low toxicity, and electrical conductivity, making them promising materials for sensors and biological devices. ,− Sensing electronic whiskers, which rely on the hysteresis effect of LM, can be realized by leveraging the fluidic properties of LM . A tilt angle detection sensor can also be fabricated using LM .…”

Bioinspired Integrated Auxetic Elastomers Constructed by a Dual Dynamic Interfacial Healing Strategy

“…The first strategy focuses on the formation of additional dynamic forces, such as hydrogen bonding, [15,16] metal-ligand coordination, [17,18] and ionic interactions, [19] to reinforce elastomers. The second strategy incorporates functional additives like nanostructured carbon, [20,21] metals, [22] and low-melting-point alloys [23] into elastomer matrices to improve mechanical performance. Nevertheless, the materials with the first strategy often suffer from low bond energy of reversible associations and cannot get sufficient enhancement in mechanical properties as demanded.…”