  Architected materials derive their properties from the geometric arrangement
of their internal structural elements, rather than solely from their chemical
composition. They can display remarkable behaviors such as high strength while
being lightweight, negative Poisson's ratios, and shear-normal coupling.
However, architected materials so far have either exhibited solid-like or
fluid-like behavior, but not both. Here, we introduce a class of materials that
consist of linked particles assembled in three-dimensional domains, forming
polycatenated architected materials (PAMs). We propose a general framework for
PAMs that translates arbitrary crystalline networks into particles'
concatenations and design particles' geometry. The resulting materials are
cohesive, yet the individual particles retain some kinematic freedom. In
response to small external loads, PAMs behave like non-Newtonian fluids,
showing both shear-thinning and shear-thickening responses. At larger strains,
PAMs behave like solids, showing a nonlinear stress-strain relation, like
lattices and foams. These responses are regulated by a jamming transition
determined by the particles' arrangement and the direction of loading. PAMs are
scalable, showing comparable mechanical responses at both millimeter- and
micrometer-scales. However, micro-PAMs can change shape in response to
electrostatic charges. PAM's properties are relevant for developing
stimuli-responsive materials, energy-absorbing systems and morphing
architectures.
