Scientists from the KoreanJeonbuk National University和中国材料提供商Wuhan Chamtop具有3D印刷的新型可穿戴自动传感器。
Based on a unique barium-loaded PVDF polymer, the team’s fully-printed devices are effectively able to harvest the piezoelectric energy generated by human movement. When built into an array, the sensors proved capable of using this charge to detect pressure inputs and convert them into signals, a significant advance in the development of high-performance additive wearable electronics.
Piezoelectric-powered electronics
Given the potential of self-powered sensors in creating wearable medical or sports-related monitoring devices, it’s hardly surprising that they’ve become an increasingly hot topic of research. As opposed to normal battery-operated actuators, self-powered technologies are often more compact and eco-friendly, while being cheaper to make as well.
Piezoelectric devices hold particular promise in this area thanks to their flexibility, net power output and ease of fabrication, in addition to improved performance compared to triboelectric energy sources (e.g. static). While PVDF has emerged as a popular base material for 3D printing these sensors, it often needs to be filled with a nucleating additive, in order to achieve its optimal piezoelectric performance.
In previous studies, mixing the material with polymers has yielded devices with limited efficacy, while adding barium titanate (BTO) has been found to boost desirable properties, but caused particle aggregation. To combat this, the scientists have proposed 3D printing sensors using similar ingredients, albeit in a novel ‘mortise–tenon-shaped’ structure.
3D打印传感器阵列
一旦研究人员确定了最佳PVDF-BTO公式，他们就部署了Musashi Engineering机器人手臂安装的3D打印机，将材料分配到胶片中。然后将银糊印在设备的表面上，然后使用镍胶带标记其电极，并在电场下进行螺栓。
The resulting sensors were arranged into a U-shaped 7 × 7 cm2数组并进行表征测试。最初的结果表明，树脂中没有明显的BTO沉淀，这是潜在工业应用的重要先驱。有趣的是，该小组还发现，薄膜中BTO浓度水平的提高对其压电特性产生了相关的影响。
For instance, those prototypes consisting of 10% barium nanoparticles (NPs) exhibited a current of 24.3 pC/N, while loading the samples with a concentration of 50%, increased this to 69.1 pC/N. Given their optimal performance, the latter sensors were later deployed within sporting evaluations, in which they were fitted to taekwondo protective gear.
When struck, the devices were able to detect the different levels of force applied based on the amount of voltage generated, something that could prove useful as an athlete training tool. Given the flexibility of their array, the scientists also propose that it could be 3D printed onto other wearables in future, enabling them to monitor various sporting activities without the need for external power sources.
Piezoelectric’s electrifying potential
3D printing with piezoelectric materials enables the production of battery-less devices with moving parts that could prove ideal for all sorts of clinical and soft robotic applications.
Scientists from theUniversity of Wisconsin-Madisonhave utilized the technology to3D打印血管capable of remotely monitoring a patient’s blood pressure. The tubular devices emit piezoelectric pulses, alerting patients to when they need to seek urgent medical attention, without the need for an external power source.
同时，一个中国研究人员的联盟3D打印了一个自动机器人手指that’s able to sense changes in curvature without using a conventional battery. The team hope that their multi-material additive digit will inspire the development of other piezo-powered soft robotics in future.
When it comes to novel materials, engineers from theVirginia Polytechnic Institute and State Universityhave also made significant advances. In recent research conducted there, a team developed aDLP 3D打印的压电陶瓷, and used it to create various complex self-sustaining structures.
The researchers’ findings are detailed in their paper titled “Mortise–tenon joint structured hydrophobic surface-functionalized barium titanate/polyvinylidene fluoride nanocomposites for printed self-powered wearable sensors.” The research was co-authored by Hai Li, Hoseong Song, Mengjie Long, Ghuzanfar Saeeda and Sooman Lim.
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特色图片显示了该团队的3D打印传感器在跆拳道腰带中测试的图。图像通过Nanoscale Journal。
