Stressing the Limits of Piezoelectricity

强调压电的局限性

• 批准号: RGPIN-2022-05125
• 负责人: Zednik, Ricardo
• 金额: $ 2.04万
• 依托单位: École de technologie supérieure
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754532
• 关键词: Stressing; Limits; Piezoelectricity

Piezoelectric materials have the reversible ability to convert between a mechanical strain and an electric field: this behavior touches our daily lives, enabling accelerometers, air-bag sensors, and microphones that are essential for the aerospace, automotive, and consumer electronics industries - all important branches of the Canadian economy. Controlling the behavior of these materials is generally attempted by varying the composition or chemistry, with limited success. Instead, we explore a complementary approach: how can an applied mechanical stress be harnessed to enhance the properties of piezoelectric materials? For example, piezoelectric properties decay with increasing temperature, and disappear once the Curie Temperature is reached, typically in the range of 25-250 °C. We will use stress engineering to enable lithium niobate (LiNbO3) to finally overcome this limitation, thereby allowing piezoelectric sensors to finally operate at temperatures exceeding 700 °C. This will allow the real-time health monitoring of critical high temperature systems to predict (and prevent) catastrophic failure, such as in aircraft turbine engines, nuclear reactors, or petrochemical plants. The vast majority of piezoelectric devices employ normal mechanical strains (i.e. deformation parallel or perpendicular to the electric field). This strain mode has allowed engineers to develop a wide range of important applications (guitar pick-ups, sonar, neonatal ultrasounds, etc.). However, what if a material existed that could instead twist in pure torsion when exposed to an electric field? Tellurium dioxide (TiO2) is predicted to be such an exceptional piezoelectric material. We will perform the necessary experimental confirmation and study the effect of mechanical stress on this interesting behavior. The revolutionary novel applications enabled by this unique geometry would include nanoscale gyroscopic accelerometers for use in airplanes, satellites, and cell phones. In general, most piezoelectric materials are rigid, brittle ceramics. Piezoelectric polymers have only very limited applications due to a polymer's relatively small piezoresponse, orders of magnitude lower than ceramics. However, some applications require the mechanical flexibility, biocompatibility, low cost, form factor, and manufacturability that only polymers can provide. We will therefore use mechanical stress engineering to build the first true polyvinylidene fluoride (PVDF) polymer nanofiber piezoelectric device. The consequences of realizing such a smart polymeric nanofiber, one thousand times thinner than a human hair, cannot be overstated: imagine artificial skin that can "feel" temperature and pressure, a T-shirt that can monitor your heartbeat, or an aircraft wing that measures its own deformation in-flight. Mechanical stress engineering can help overcome the temperature, geometry, and mechanical limitations of these promising piezoelectric materials.

压电材料具有在机械应变和电场之间进行可逆转换的能力：这种行为与我们的日常生活息息相关，使加速计、安全气囊传感器和麦克风成为航空航天、汽车和消费电子行业必不可少的产品 - 非常重要通常通过改变成分或化学成分来控制这些材料的行为，但效果有限。相反，我们探索了一种补充方法：如何利用施加的机械应力来增强压电材料的性能？为了例如，压电特性随着温度的升高而衰减，一旦达到居里温度（通常在 25-250 °C 范围内），压电特性就会消失。我们将使用应力工程使铌酸锂 (LiNbO3) 最终克服这一限制，从而允许压电。传感器最终能够在超过 700°C 的温度下运行，这将使关键高温系统的实时健康状况监测能够预测（并防止）灾难性故障，例如飞机涡轮发动机、核能系统。绝大多数压电设备都采用正常的机械应变（即平行或垂直于电场的变形），这种应变模式使工程师能够开发出广泛的重要应用（吉他拾音器、声纳、然而，如果存在一种在暴露于电场时可以发生纯扭转的材料，那么二氧化碲 (TiO2) 预计将成为一种特殊的压电材料。我们将进行必要的实验确认并研究机械应力对这种有趣行为的影响，这种独特的几何形状所带来的革命性新颖应用将包括用于飞机、卫星和手机的纳米级陀螺仪加速度计。压电聚合物是刚性、脆性的陶瓷，由于聚合物的压电响应相对较小，比陶瓷低几个数量级，因此其应用非常有限。因此，我们将使用机械应力工程来构建第一个真正的聚偏二氟乙烯 (PVDF) 聚合物纳米纤维压电器件，实现这种智能聚合物纳米纤维的效果，其厚度比它薄一千倍。人类的头发，怎么强调都不为过：想象一下可以“感觉”温度和压力的人造皮肤，可以监测心跳的 T 恤，或者测量自身变形的飞机机翼飞行中的机械应力工程可以帮助克服这些有前途的压电材料的温度、几何形状和机械限制。