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Thia-Michael-based dynamic polymer glasses have been designed that exhibit a range of room-temperature mechanical properties when subjected to varying temperatures during tempering, resulting in these materials acting as tunable adhesives. 

Training has emerged as a promising materials design technique in which function can be achieved through repeated physical modification of an existing material rather than by direct chemical functionalization, cutting, or reprocessing. This work investigates both the ability to train for function and then to erase that function on-demand in macroscopic metamaterials made from liquid crystal elastomers. We first show that the Poisson’s ratio of these disordered arrays can be tuned via directed aging to induce an auxetic response. We then show that the arrays can be reset and retrained for another local mechanical function, allostery, thus demonstrating pluripotent functionality. 

The morphological features of particles, notably shape anisotropy, critically influence the rheological properties of dense suspensions, spanning both natural and engineered systems. This work explores the potential of using shape memory particles to dynamically regulate suspension fluid flow through controllable shape transformations. First, we synthesize shape-memory particles with programmable anisotropy from liquid crystal elastomers, such that the stiffness and shapes of the particles can be tuned by manipulating temperature. Our findings reveal that suspensions from such particles exhibit significant tunability in shear thickening behavior, transitioning from discontinuous shear thickening to a Newtonian-like response within a narrow temperature range of 60 ${}^{°}$ C. This capability to modulate rheological responses in situ presents an approach for addressing processing challenges in many applications where control over flow behavior is paramount. Furthermore, we also show that suspensions composed of these anisotropic particles can undergo physical aging, and evolve into a glassy state. This state can be escaped upon activation of the shape memory effect. This reversibility underscores the potential for using such materials to engineer systems that can enter or come out of kinetic arrest by leveraging internal mechanical responses to external stimuli. The insights gained here not only broaden our understanding of the interplay between particle geometry and suspension dynamics but also pave the way for leveraging ensembles of stimuli-responsive objects to precisely control collective behaviors in many-body systems.