基于桥接式纳米结构敏感单元的纳电极集成检测微系统研究

Nanomaterials can enhance ordinary sensor performance with unique physical and chemical properties. How to construct a reasonably sensitive cell structure, sovling nano-micro integrated manufacturing problems and establishing integrated detection micro-system are important technical prerequisites for advancing the nanoelectrodes sensor toward practical application. Ultra-high-sensitivity detection of the target material can be achieved by limited nanomaterial between the two test electrodes in bridge-nanostructures sensitive unit which has become the preferred nanoelectrodes sensor sensitive cell structure. However, the traditional methods can not effectively avoid weak bonding between the bridge nanomaterials and metal electrode. In addition, these methods can not meet the needs of the bulk of the preparation and the integrated development, which greatly restricts the development of the integrated detection system. In the present program, a nano-electrodes detection microsystem has been proposed based on a clever combination of nanomaterial/polymer composite film and nano-micro processing technology. This design includes sampling, sample preparation, detection and post-processing functionality. The theoretical design method will be constructed for control the dispersed nanomaterials and implanting process of the bridged nanostructure unit. How to integrate the bridged nanostructure unit and detection micro system will be developed based on the sensitive mechanism of the unit. Finally, the fabricated detection system will be tested and characterized for evaluating its overall performance.

纳米材料凭借独特的理化性质，已成为提升普通传感器性能的利器。如何构造合理的敏感单元结构，突破纳-微集成制造难题，建立集成检测微系统，是推进纳电极传感器走向实际应用的重要技术前提。桥接式纳米结构敏感单元能够通过桥接在测试电极两端的有限数量纳米材料实现目标物超高灵敏度检测，目前已成为纳电极传感器首选的敏感单元结构。然而，传统加工方法无法有效解决桥接纳米材料与金属电极界面弱结合的问题，更不能满足其批量化制备和集成化发展的需求，极大的制约了其集成检测系统的发展。本项目基于纳米材料/聚合物复合物薄膜，巧妙组合微加工工艺构造纳-微跨尺度集成工艺路线，在此基础上提出一种集采样、制样、检测及后处理功能于一体的桥接式纳电极集成检测微系统设计。项目将建立针对桥接式纳米结构单元制备的纳米材料分散操控和可控植入的理论设计方法，开展桥接式纳米结构单元集成制备和敏感机制功能化集成系统研究，并通过原型器件验证设计思想。

碳纳米管被发现以来，因其优异物理性质、稳定的化学性质和优良的电学性能受到科学界的广泛关注，碳纳米管与传统材料相比有较大的比表面积，可为化学反应或者物理吸附提供充足的反应场所。碳纳米管因吸附不同气体而产生电学性能的变化，该特性为其应用于气体的检测系统的敏感单元提供了条件。课题组对利用微加工工艺将一维纳米材料碳纳米管应用于气体检测展开研究。课题组首先解决了一维纳米材料与毫米级基底材料结合力差的问题。开发单端植入电极基底的工艺，课题组首先利用无机材料水玻璃，将碳纳米管单端植入玻璃基底，制备了单端植入玻璃基底电极。该电极电化学性能稳定可靠，为检测分析碳纳米管与基底结合的可靠性，我们将单端植入玻璃基底电极至于强电场下，因碳纳米管与基底结合力牢固，该电极表面裸露的碳纳米管尖端展现了优异的场发射性能。基于将一维纳米材料植入基底表面，课题组又开发了基于微加工工艺的将一维纳米材料植入金属电极表面的方法，该方法不但有效解决了一维纳米材料与金属基底结合差的问题，还成功实现了基于微加工工艺的一维纳米材料单端植入金属基底的批量制造。该金属基单端植入碳纳米管电极具有优异的机械性能之外兼具稳定的电学性能，即使在大角度弯曲条件时仍能持续稳定的进行电子发射。基于上述碳纳米管单端植入的电极的研究，课题组进行将碳纳米管双端植入金属电极的工艺开发。课题组成功制备了垂直双端植入金属电极和水平双端植入金属电极，并成功将其应用于气体检测。最后，课题组利用碳纳米管水平双端植入金属电极作为敏感单元，同时集成微流道采样单元，制热取样单元和测试室单元的集成检测微系统，并对其气体敏感性进行了测试。制备的传感器具有良好的敏感性和可重复性，该系统展现了良好的应用前景。