Print, pattern, stick: low-cost gecko-inspired adhesives using embedded diffraction structures

Gecko-inspired adhesives offer strong, reversible, and directionally tunable adhesion, yet fabrication methods often depend on cleanroom lithography or proprietary molds, limiting scalability and accessibility. This study presents a low-cost, modular fabrication strategy combining high-resolution digital light processing 3D printing with 1000 lines/mm optical diffraction gratings to create hierarchical elastomeric adhesives. The resulting structures feature macroscale micropillars and embedded sub-micron surface topography, enabling effective contact splitting without advanced microfabrication. Mechanical testing reveals a nonlinear increase in shear performance with contact area, with maximum shear forces exceeding 80 N at 103.2 cm². Peel testing across varied angles and surface areas demonstrates anisotropic adhesion, with peak peel strength of 21.94 N and detachment energy of 3.88 Jm-2at a 30° peel angle for patch area of 103.2 cm². A comparative cost analysis highlights the accessibility of this method, revealing a 10-100xreduction in fabrication cost relative to cleanroom and roll-to-roll-based techniques. This approach enables reproducible microstructure transfer, optical validation, and application-specific tunability, offering a practical, scalable pathway for bio-inspired adhesives in robotics, wall-climbing systems, and soft interface applications.