Episode 8: Knots tied within microstructure of foam

In this podcast episode, MRS Bulletin’s Sophia Chen interviews Widi Moestopo, a former graduate student in Julia Greer’s laboratory at the California Institute of Technology (Caltech) and now a postdoc at Lawrence Livermore National Laboratory about their work incorporating microknots in architected materials. Using two-photon lithography, Moestopo scans a resin with a laser to create and shape a three-dimensional (3D) object within foam. Moestopo then used a solvent to wash away the remaining, unconverted resin. In this way, he sculpted the knots out of the resin, rather than tying the knots like shoelaces. This 3D structure is formed from a lattice of 3D rhombuses, where each side of the rhombus consists of three strands of fiber. These fibers are woven around each other to form knots. The result is a materials with high deformability and tensile toughness. This work was published in a recent issue of Science Advances.