Production and characterization of parylene C based flexible pressure sensor

This thesis covers the use of parylene C, which is used as a protective layer in MEMS applications, as a flexible pressure sensor after the discovery of its piezoelectric properties in 2011. First, parylene C was synthesized by chemical vapor deposition. Composite samples were prepared by the addition of polyurethane (PU), poly (methyl methacrylate) (PMMA) and activated carbon in certain weight ratios. Structural, chemical, morphological and thermal analyses of the samples were carried out. By electromechanical measurements, piezoelectric, piezoresistive and capacitive properties were determined, sensing performances were analyzed and the best performing flexible pressure sensor candidates were identified. Pressure-sensitive inks prepared by taking into account the formulation of the determined candidate samples were prepared again in accordance with the screen printing method and flexible pressure sensors were produced by screen printing method. The electromechanical measurements show that parylene C-based samples with low pressure sensing performance cannot be used as flexible piezoelectric pressure sensors. The pressure sensing range of the flexible piezoresistive and capacitive pressure sensors was determined as P<1.5 kPa, with sensitivities of 0.152 kPa-1 and 0.124 kPa-1, respectively.