Growth-Like Swelling of 2D Precursors for Efficient Fabrication of Complex 3D Microstructures.

3D microstructures have offered the potential for performance enhancement in nearly every type of microsystem. Although traditional solvent-induced swelling can easily and efficiently fabricate some complex 3D microstructures, their 3D morphology can be maintained only in a solvent environment, which severely limits the applications of these 3D microstructures. Here, we present a fabrication method to induce photocurable monomers into elastomeric microstructures to generate a buckling deformation of the microstructures, which is stable and irreversible after photo-curing. This process is applicable to a variety of elastomeric polymers, photocurable monomers, and solvents. A 4-inch sample of these 3D microstructures can be efficiently fabricated within 5-20 min. Moreover, it is compatible with imprinting processes, thereby further expanding both the material applicability and manufacturing efficiency for 3D microstructures. Meanwhile, a variety of complex 3D microstructures are obtained by controlling the growth-like swelling cycles and the shape of 2D precursors. To demonstrate the enormous potential of this growth-like swelling process, we use this strategy to fabricate octopus-inspired 3D micro-sucker arrays for underwater adhesion.