Cryogenic printing of three-dimensional soft iontronic sensors

Jinhao Li, Jie Cao, Yi Zhao, Guoying Gu

Keywords: Soft sensor; Lattice structure; 3D printing hydrogel; Human-robot interface

Abstract: Designing soft iontronic skin for tactile sensing facilitates natural human-machine communications. However, the nonlinear characteristics of electrical transductions and mechanics usually compromise precise tactile decoding, requiring tailored three-dimensional architectures for responses. Herein, we propose a multimaterial cryogenic printing (MCP) technique that harnesses a universal all-in-cryogenic solvent phase transition strategy. We, therefore, can facilely fabricate sophisticated hydrogel structures with high aspect ratio geometries in high fidelity. Using this approach, we present a soft 3D-structured pressure sensor featuring a PEDOT:PSS-PVA hydrogel lattice encapsulated within an origami-inspired elastomeric framework. Our 3D lattice sensor enables wide-range linearity in both electrical responses (R2 = 0.993±0.005 within 0-220 kPa) and compressive mechanics (~49.5% strain) without sacrificing tissue-like compliance. Further integration as human-machine interfaces facilitates accurate pressure input for wearable robotic teleoperation and an intelligent fingertip for safely detecting soft tissue modulus.

Submission Number: 22