Post‐Processing Strengthened 3D Artificial Fingertip with Multi‐Intensity Pain Perception

Artificial electric skin with multi-intensity pain-evaluating capabilities offers promising opportunities for the construction of friendly human-robot interaction. However, realizing a stepwise sensing system generally requires lateral integration of diverse materials, which is prone to delamination and thus operation failure. Here, a fully soft, monolithic hydrogel-based artificial fingertip (HBAF), fabricated via digital light processing (DLP) 3D printing, enabling robotic fingertips to distinguish objects in varying sizes is proposed. To enhance the mechanical and conductive properties of a printed hydrogel, a two-step post-processing method is developed to introduce a secondary functional network into a high-resolution soft model. This modification can increase stretchability by three-fold and conductivity by 1.78-fold compared to the original printed hydrogel. Notably, the integration challenge between the hydrogel-based sensor and the robotic body part is addressed by growing a polydopamine gel layer at the interface of the 3D model's base to enhance contact. Furthermore, the HBAF's size parameters can be programmed to achieve distinct pain thresholds, demonstrating its potential for personalized bionic sensors in artificial limbs and enhancing safety in collaborative robotics.