We achieve the benefits of large-scale structural hierarchy at the micro-scale by utilizing a self-propagating photopolymer waveguide process to form ultra-thin sandwich structures. A single step forms the microlattice sandwich core and bonds the core to both facesheets, minimizing adhesive mass and manufacturing time, with core thicknesses <2 mm, facesheet thicknesses ranging from 12.7 to 300 μm, areal densities 0.030–0.041 g cm−2, and flexural rigidity per unit width up to 0.62 Nm. This work extends the lightweighting benefit of sandwich structures to lower thicknesses and areal densities that were previously the exclusive domain of monolithic materials.
