Piezoresistive sensor production using biomimetic and hybrid patterns

Wearable electronics have been one of the leading research topics in sensor technology in recent years, with easy production methods that include features such as flexibility, durability, and functional diversity. Wearable electronics can define the changes in the human body can be monitored by; electronic clothing items, GPS-based tracking devices, and personal video recorders, etc. As smart wearable electronics become more widespread, the requirements for flexible, durable, and breathable electrodes that are easily compatible with electronics and meet the needs of users when used for a long time are also increasing. Biomimicry science works on understanding the characteristics of organisms found in nature, imitating these characteristics, and integrating them into application areas. Biomimicry studies can be realized in areas such as artificial neural networks, biological sensing systems, synthesis of biological materials, biofuel production, biological data processing, and optimization of biological systems. These studies provide an understanding of effective and efficient processes in nature, which can provide innovative solutions for various industrial, environmental, or medical applications. In this thesis study, to contribute to the field of biomimicry applications, the patterns of carp fish (Cyprinus carpio) scales were molded and imitated with PDMS, and their usability for the sensor active layer was investigated. PEDOT: PSS polymer was coated on these patterns with the Ultrasonic Spray Pyrolysis (USP) method to ensure electrical conductivity and after producing piezoresistive sensors the characterization processes carried out. Carp fish scale patterns were successfully molded with PDMS polymer for the first time in this study. PEDOT: PSS polymer was deposited on a fish-scale patterned PDMS mold using USP, a cost-effective thin film coating method with simple production steps. After the fish scale patterned PDMS were coated with PEDOT: PSS, they were contacted with silver paste, the active surfaces were adjusted to contact each other, and the current mechanism was measured under different voltage values. The response and recovery times of the optimized bioinspired and inorganic patterned sensors are below 100 ms and agree with the literature. In addition to fast response and recovery times, the sensors have also been tested for durability and have been shown to be operable at pressures above 50 MPa. The sensors, whose reactions were tested against a wide range of forces such as mechanical actuators, heartbeat signals, and sound waves, worked successfully. With their ease of fabrication, cost, and reasonable response and recovery times, these bioinspired piezoresistive sensors can easily find a place in wearable electronics and IoT applications. Keywords: Biomimicry, Piezoresistive Sensor, Wearable Electronics, Ultrasonic Spray Pyrolysis.