Instrument Development: Multiplex Sensory Interfaces Between Photonic Nanostructures and Thin Film Ionic Liquids

以高度敏感的方式识别和测量天然存在或排放的气体和金属物质的数量对于确保公众的福利至关重要;第一响应者，军事人员和高风险工作场所环境中员工的安全;以及评估气体和金属影响的能力是可持续全球环境的关键。该项目开发了一种未开发的化学传感方法，该方法基于当遇到气体或金属离子的微小水平时光束的位置被移动。一个由化学家、物理学家和工程师组成的团队正在利用光波在涂有环保离子液体薄膜的纳米金属层表面反弹时的特性。该项目旨在提供前所未有的，低成本的监测大气气体和环境中的金属离子，在各种条件和地点。使用这种新方法的小型传感器的大规模生产有可能被各行各业的人们广泛使用。这项研究的多学科协作性质影响了研究生和本科生的教育，他们是使用团队合作的方法进行培训的。为了鼓励代表性不足群体的高中生获得教育机会，通过联合举办的讲习班对来自东克利夫兰学区的实习生进行培训。该研讨会包括讲座和实验室部分，重点是工程和科学之间的跨学科研究如何解决当前和迫切的社会需求。在化学系化学测量和成像项目的支持下，教授B。Gurkan、Hinczweski、Strangi和U.凯斯西储大学的Gurkan正在致力于开发一种新的“通用”方法来检测气体和金属离子。该研究的三个具体目标是：（1）设计光子纳米结构，以显著增强入射激光束的古斯-汉臣（GH）位移，从而能够超灵敏地检测局部介电常数变化;（2）了解纳米结构上方的离子液体层的折射率变化，在存在溶质如二氧化碳和金属盐的情况下;以及（3）评估多路复用接口的灵敏度和响应性。传感机制基于GH位移，其中在棱镜表面处内反射的激光束沿该表面沿着位移。GH位移的大小取决于棱镜顶部材料的结构和折射率，包括离子液体层。光子纳米结构放大了GH位移的幅度，使其变得容易检测。光子纳米结构由具有不同层次排列和结构的交替电介质或金属层组成，通过计算设计并通过纳米纤维制造。为了抑制干扰，在顶层使用不同的离子液体进行多路复用，并在暴露于目标分析物时调整介电常数变化。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Identifying and measuring the amount of naturally occurring or emitted gases and metal species in a highly sensitive way is critical for ensuring the welfare of the public; the safety of first responders, military personnel, and employees in high-risk workplace settings; and the capability to assess the impact of gases and metals that are key to a sustainable global environment. This project develops an unexplored chemical sensing method that is based on the position of light beams being shifted when minute levels of a gas or metal ion are encountered. A team of chemists, physicists, and engineers is taking advantage of the properties of light waves when they bounce off the surface of nanometer-sized metal layers coated with thin films of environmentally friendly ionic liquids. The project aims to offer unprecedented, low-cost monitoring of atmospheric gases and metal ions in the environment, under a wide variety of conditions and locations. Mass production of miniaturized sensors that use the new method has the potential for widespread use of the sensors by people from many walks of life. The multidisciplinary collaborative nature of this research impacts the education of graduate and undergraduate students who are trained using a teamwork approach. To encourage educational opportunities for high school students from underrepresented groups, student interns from the East Cleveland School District are trained through a jointly organized workshop. The workshop has lecture and laboratory components and focuses on how the cross-disciplinary research between engineering and science can address current and pressing needs in society.With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professors B. Gurkan, Hinczweski, Strangi, and U. Gurkan at Case Western Reserve University are addressing development of a new "universal" method for the detection of gases and metal ions. The three specific aims of the study are: (1) engineering a photonic nanostructure to dramatically enhance the Goos-Hanchen (GH) displacement of an incident laser beam, allowing for ultrasensitive detection of local permittivity changes; (2) understanding of the refractive index changes of the ionic liquid layer above the nanostructure, in the presence of solutes such as carbon dioxide and metal salts; and (3) evaluating sensitivity and responsiveness of the multiplex interface. The sensing mechanism is based on GH displacement, where a laser beam internally reflected at a prism surface is displaced along the surface. The size of the GH shift depends on the structure and refractive indices of the materials on top of the prism, including the ionic liquid layer. The photonic nanostructure amplifies the magnitude of the GH shift so that it becomes easily detectable. The photonic nanostructure consisting of alternating dielectric or metal layers with different hierarchical arrangements and architectures are computationally designed and created by nanofabrication. To suppress interferences, multiplexing is employed by the use of different ionic liquids on the top layer with tailorable permittivity changes upon exposure to target analytes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.