A 3D printed liquid metal emulsion for low stress activated stretchable electronics
A 3D printed liquid metal emulsion for low stress activated stretchable electronics
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DOI：
10.1177/00219983221149255
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发表时间：
2023-01
影响因子：
2.9
通讯作者：
Ramón E Sánchez Cruz;S. F. Zopf;J. Boley
中科院分区：
文献类型：
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作者：
Ramón E Sánchez Cruz;S. F. Zopf;J. Boley
报道了一种用于柔性导电复合材料可编程组装的应变诱导导电液态金属乳液。该乳液表现出直接油墨书写所需的剪切屈服和剪切稀化流变性。呈现具有跨越特征的复杂自支撑3D打印结构的示例以证明该乳液的3D可打印性。可拉伸的液态金属复合材料是通过将这种乳液整合到具有3D可打印弹性体的多材料打印过程中来制造的。印刷的复合材料表现出低电导率，但可以通过在低应力（<0.3MPa）下的单个轴向应变转变成高导电复合材料，比其他机械烧结方法低一个数量级。轴向应变和循环载荷对这些复合材料的电导率的影响的特点。电导率随着活化应变的增加而增加，观察到的最大弛豫电导率为8.61 × 105 S·m-1，比其他机械烧结方法高出300%以上。这些复合材料的电导率在一个循环后对于每个应变达到稳定状态，在1000个循环中保持稳定，具有低变化（<6%标准偏差）。定量分析了这些复合材料的应变灵敏度。所有样品在所有应变中都表现出低于体导体的应变灵敏度。印刷复合材料在高应变下表现出低滞后，在低应变下表现出高滞后，这可能受到乳液内部结构的影响。这些复合材料的效用是通过采用它们作为布线到一个单一的制造过程中的可拉伸的LED阵列。
A strain-induced electrically conductive liquid metal emulsion for the programmable assembly of soft conductive composites is reported. This emulsion exhibits the shear yielding and shear thinning rheology required for direct ink writing. Examples of complex self-supported 3D printed structures with spanning features are presented to demonstrate the 3D printability of this emulsion. Stretchable liquid metal composites are fabricated by integrating this emulsion into a multi-material printing process with a 3D printable elastomer. The as-printed composites exhibit a low electrical conductivity but can be transformed into highly conductive composites by a single axial strain at low stresses ( < 0.3 MPa), an order of magnitude lower than other mechanical sintering approaches. The effects of axial strain and cyclic loading on the electrical conductivities of these composites are characterized. The electrical conductivity increases with activation strain, with a maximum observed relaxed conductivity of 8.61 × 105 S⋅m−1, more than 300% higher than other mechanical sintering approaches. The electrical conductivity of these composites reaches a steady state for each strain after one cycle, remaining stable with low variation ( < 6 % standard deviation) over 1000 cycles. The strain sensitivities of these composites are quantitatively analyzed. All samples exhibit strain sensitivities that are lower than a bulk conductor throughout all strains. The printed composites showed low hysteresis at high strains, and high hysteresis at low strains, which may be influenced by the emulsion internal structure. The utility of these composites is shown by employing them as wiring into a single fabrication process for a stretchable array of LEDs.