Sonication-Free Pollen Microgel-Enabled CNT Conductive Inks with 3D/Screen Printability and Layered Self-Assembly

Sustainable, high-performance conductive inks are crucial for next-generation wearable electronics. While biopolymer-based dispersants offer renewable and biocompatible routes for stabilizing carbon nanotube (CNT) inks, a critical paradox persists: utilizing molecular biopolymers typically requires energy-intensive extraction, depends on high-power ultrasonication for debundling, and lacks the rheological strength needed for precision extrusion printing. Here, we present a sonication-free strategy utilizing sunflower pollen microgels in their native, soft granular state. Leveraging the pollen’s amphiphilic, spiky architecture, we achieve CNT debundling through mechanically driven colloidal collisions, while a synergistic alginate corona provides electrostatic stabilization. The resulting pollen–alginate–CNT (PAC) inks exhibit rapid thixotropy and high viscoelasticity, enabling high-fidelity 3D extrusion and screen printing. Uniquely, drying induces a layered self-assembly, where microgels collapse into lamellar architectures to form anisotropic conductive networks. These structural features unlock multifunctional performance, including humidity sensing via interlayer-spacing modulation, direction-dependent strain sensing, and outstanding electromagnetic interference shielding. This work establishes a scalable, energy-efficient particulate-stabilizer framework that overcomes the processing and rheological limitations of conventional bio-based inks, advancing sustainable, adaptive printed electronic systems.