Integrated Electromechanical Transduction Schemes for Polymer MEMS Sensors

Abstract

Polymer Micro ElectroMechanical Systems (MEMS) have the potential to constitute a powerful alternative to silicon-based MEMS devices for sensing applications. Although the use of commercial photoresists as structural material in polymer MEMS has been widely reported, the integration of functional polymer materials as electromechanical transducers has not yet received the same amount of interest. In this context, we report on the design and fabrication of different electromechanical schemes based on polymeric materials ensuring different transduction functions. Piezoresistive transduction made of carbon nanotube-based nanocomposites with a gauge factor of 200 was embedded within U-shaped polymeric cantilevers operating either in static or dynamic modes. Flexible resonators with integrated piezoelectric transduction were also realized and used as efficient viscosity sensors. Finally, piezoelectric-based organic field effect transistor (OFET) electromechanical transduction exhibiting a record sensitivity of over 600 was integrated into polymer cantilevers and used as highly sensitive strain and humidity sensors. Such advances in integrated electromechanical transduction schemes should favor the development of novel all-polymer MEMS devices for flexible and wearable applications in the future.

Recent advances in ion sensing with conducting polymers

“…Molecular recognition: Analyte interacts with the receptor material and shows affinity for the selective analyte under chemical reaction. A recognition element (R) can be designed, in which an analyte (A) and a receptor interacts and gives the product of analyte-receptor interaction (P) under chemical equilibrium [87], Transduction: Involves the transfer of chemical information to measurable electrical (change in electrical signal), optical (change in colour) or thermal (change in heat) signals, which in turn define the quantity of absorbed specific analyte [88].…”

The Fabrication of Micro Beam from Photopolymer by Digital Light Processing 3D Printing Technology

“…MEMS technologies have been manufactured by traditional methods such as lithography, galvano forming, and photolithography etc. These methods are dependent on additive or subtractive procedures that operate minuscule capacities of materials in the shape of thin layers on the surface of silicon wafers [12][13][14][15][16]. These conventional techniques are extremely precise and appropriate for the production of planar geometries [17].…”

Real-Time Frequency Tracking of an Electro-Thermal Piezoresistive Cantilever Resonator with ZnO Nanorods for Chemical Sensing

“…In dynamic mode operation, MEMS cantilever sensors have normally been operated as micro-resonators, in which their resonant frequency shift (∆f 0 ) can be monitored as their mass changes due to the adsorption/desorption of analytes on/from the sensitive layer. Sensor characterization by frequency sweeping is one of the most common methods used to figure out the amplitude and phase responses, and finally identify the resonant frequency [5][6][7]. However, regardless of the set during sweeping, this technique is not feasible for fast real-time measurement of resonance shifting.…”