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<b>^-</b>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.