Scalable Fabrication of Flexible Tactile Sensors Using Additive Manufacturing and Polyvinyl Alcohol-Assisted Carbon Nanotube Transfer

We present a polyvinyl alcohol (PVA)-assisted carbon nanotube (CNT) transfer printing process that enables the fabrication of highly sensitive and mechanically stable tactile sensors. By leveraging fused filament fabrication 3D printing, we designed a hierarchical microstructured surface, which facilitates controlled CNT integration while ensuring strong adhesion. Structural and electrical characterizations demonstrated the effectiveness of the proposed method. Scanning electron microscopy and confocal microscopy analyses confirmed the precise formation of CNT-embedded microstructures, while electrical measurements revealed a pressure-dependent sensitivity transition. The sensor exhibited distinct sensitivity regions, achieving a high sensitivity of 4.14487 kPa-1 in the low-pressure regime, which gradually decreased as the microstructures compressed under higher pressures. Cyclic pressure loading tests further validated the sensor's repeatability, robustness, and ability to distinguish different pressure levels. These results indicate that the PVAbased CNT transfer printing process provides a scalable and efficient approach for fabricating high-performance tactile sensors with enhanced adhesion, sensitivity, and durability. The proposed method is expected to contribute to the development of next-generation flexible sensing technologies, particularly in applications requiring reliable and highly responsive pressure detection.