Partially Embedded Carbon Nanotube Bundles in an Elastomer Matrix for Highly Sensitive and High-Spatial-Resolution Tactile Sensing

Flexible tactile sensors have attracted significant attention owing to their potential applications in various fields, such as human–machine interfaces and wearable devices. However, many previous studies have been limited by low sensitivity and insufficient spatial resolution. In this study, we developed high-resolution tactile sensor arrays integrated with vertically aligned carbon nanotube (VACNT) bundles, achieving a spatial resolution with a 1 mm pitch. The patterned VACNT bundles are synthesized on a micropyramidal silicon mold and subsequently transferred onto a polymer substrate to form a pressure-sensitive layer. The VACNTs were synthesized via a chemical vapor deposition process, resulting in excellent uniformity with only 4.23% variation among the pressure-sensing cells. When pressure was applied, the contact area increased both between the exposed VACNT strands and the electrodes, and among the VACNTs embedded within the polydimethylsiloxane matrix. This dual-contact mechanism led to a high sensitivity of 40.6 kPa–1 across a pressure range of 0–100 kPa. Leveraging these advantageous properties, we successfully demonstrated a pressure distribution measurement system capable of detecting both the magnitude and spatial distribution of subtle pressure.