Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, China.
PLoS One. 2012;7(9):e45485. doi: 10.1371/journal.pone.0045485. Epub 2012 Sep 19.
Conventional approaches of making a flexible circuit are generally complex, environment unfriendly, time and energy consuming, and thus expensive. Here, we describe for the first time the method of using high-performance GaIn(10)-based electrical ink, a significantly neglected room temperature liquid metal, as both electrical conductors and interconnects, for directly writing flexible electronics via a rather easy going and cost effective way.
The new generation electric ink was made and its wettability with various materials was modified to be easily written on a group of either soft or rigid substrates such as epoxy resin board, glass, plastic, silica gel, paper, cotton, textiles, cloth and fiber etc. Conceptual experiments were performed to demonstrate and evaluate the capability of directly writing the electrical circuits via the invented metal ink. Mechanisms involved were interpreted through a series of fundamental measurements.
The electrical resistivity of the fluid like GaIn(10)-based material was measured as 34.5 µΩ·cm at 297 K by four point probe method and increased with addition of the oxygen quantity, which indicates it as an excellent metal ink. The conductive line can be written with features that are approximately 10 µm thick. Several functional devices such as a light emitting diode (LED) array showing designed lighting patterns and electrical fan were made to work by directly writing the liquid metal on the specific flexible substrates. And satisfactory performances were obtained.
The present method opens the way to directly and quickly writing flexible electronics which can be as simple as signing a name or drawing a picture on the paper. The unique merit of the GaIn(10)-based liquid metal ink lies in its low melting temperature, well controlled wettability, high electrical conductivity and good biocompability. The new electronics writing strategy and basic principle has generalized purpose and can be extended to more industrial areas, even daily life.
传统的柔性电路制造方法通常复杂、不环保、耗时耗力且成本高昂。在这里，我们首次描述了一种使用高性能 GaIn(10)基电气墨水的方法，这种室温液态金属以前被严重忽视，可同时作为电气导体和互连，通过一种相当简单且具有成本效益的方式直接书写柔性电子产品。
制备了新一代电墨，并对其与各种材料的润湿性进行了修改，以便于在一组软质或硬质基底上进行书写，如环氧树脂板、玻璃、塑料、硅胶、纸张、棉花、纺织品、布料和纤维等。进行了概念验证实验，以展示和评估通过发明的金属墨水直接书写电路的能力。通过一系列基础测量来解释所涉及的机制。
通过四点探针法测量，297 K 时类似 GaIn(10)基材料的流体的电阻率为 34.5 µΩ·cm，随着氧含量的增加而增加，表明其为一种优异的金属墨水。可以用大约 10 µm 厚的特征来书写导电线路。通过直接在特定的柔性基底上书写液态金属，制作了几个功能器件，例如显示设计照明图案的发光二极管 (LED) 阵列和电扇，并使其正常工作。获得了令人满意的性能。
本方法为直接快速书写柔性电子产品开辟了道路，其简单程度如同在纸张上签名或绘图。GaIn(10)基液态金属墨水的独特优势在于其低熔点、可控制的润湿性、高导电性和良好的生物相容性。这种新的电子书写策略和基本原理具有通用性，可以扩展到更多的工业领域，甚至日常生活中。
