3D-Printed Flexible Multi-mode Sensors: From Functional Materials and Bioinspired Structures to Physically Interpretable Pressure-Torsion Decoupling

Our group’s previous studies have established two complementary routes for customized flexible sensors through digital light processing (DLP) 3D printing. At the materials level, we employ UV-curable metal-organic-framework hydrogels, conductive ionoelastomers, interpenetrating-network polyurethanes, photoluminescent elastomers, and recyclable hindered-urea-bond resins to achieve gas sensing, self-healing, degradability, mechanical robustness, optical feedback, and closed-loop remanufacturability [1,3-5,8]. At the structural level, we directly print negative-Poisson, checkerboard, microdome-labyrinth, cutaneous-inspired, and ellipsoidal architectures to regulate compressibility and transduction, enabling wide-range and small-pressure detection, contact/non-contact perception, and single-signal pressure-temperature sensing [2,4,6,7,9]. Building on this platform, we develop a DLP-printed bionic lily capacitive sensor as a novel soft multimode sensor for integrated pressure-torsion sensing and decoupling. It integrates an ion-rich elastomer, independent pressure electrodes, semicircular torsion electrodes, and grounded shielding layers. Because both inputs deform one elastomer, capacitance responses are non-unique. To our knowledge, this is the first use of a grounded shielding architecture to reveal and stabilize the relationship between the overlap area of the upper and lower electrodes and the dielectric loss factor. The shields terminate stray fringe fields, enabling the torsion-channel dielectric loss factor to vary predictably with electrode overlap. Equivalent-circuit analysis and experiments verify this mechanism. Combining this stable loss-related feature with two capacitance responses creates a three-dimensional signal space for pressure-torsion decoupling. The method successfully decouples pressure and torsion, as demonstrated by a robotic-gripper experiment under coupled-contact conditions. This progression from printable chemistry and programmable geometry to field-regulated signal construction provides a physically interpretable route toward electronic skin, wearable interfaces, and robotic tactile sensing.

Keywords: DLP 3D printing, Flexible sensor, Pressure-torsion decoupling multi-mode sensor, Dielectric loss, Bionic structure

References: Our relevant published papers

[1] Y. Zhu et al., ChemistrySelect 9 (2024) e202402571.

[2] Q. Jin et al., Macromolecular Rapid Communications 45 (2024) 2300668.

[3] X. Luo et al., Chemical Engineering Journal 483 (2024) 149330.

[4] H. Wu et al., Colloids and Surfaces A: Physicochemical and Engineering Aspects 685 (2024) 133248.

[5] C. Luo et al., Chemical Engineering Journal 501 (2024) 157761.

[6] W. Wei et al., Smart Materials and Structures 34 (2025) 015012.

[7] G. Ma et al., Composites Communications 54 (2025) 102287.

[8] Y. Feng et al., European Polymer Journal 249 (2026) 114645.

[9] Z. Deng et al., Sensors and Actuators A: Physical 406 (2026) 117928.

Dr. Yu Long received his Doctoral degree from Clemson University, USA, in 2008, and his Bachelor's and Master's degrees from Shanghai Jiao Tong University in 2000 and 2003 respectively. He is currently a Level‑2 Professor at Guangxi University. His main research interests cover additive manufacturing and laser manufacturing, robotics, industrial software and other related fields.

Over the past five years, he has led a number of research projects including the National Key R&D Program and projects funded by the National Natural Science Foundation of China. He has published more than 150 SCI‑indexed papers, obtained over 50 authorized domestic and international invention patents, and formulated 12 national standards. His awards include the Outstanding Young Manufacturing Engineer Award of SME (Society of Manufacturing Engineers, USA), the China Industry‑University‑Research Cooperation Innovation Figure Award, the First Prize of Guangxi Technical Invention Award, the Second Prize of Guangdong Science and Technology Progress Award, the Second Prize of the Awards of the China Invention Association, the First Prize of Guangxi Teaching Achievement Award (Twice), and the National Grand Prize of the "Challenge Cup" Competition (Twice).