Our system relies on the absorption of hydrophobic triblock copolymer micelles into the interstices of the colloids. Using differential scanning calorimetry, we quantify the thermodynamic transitions of the polymers to control micelle formation and uptake. With swelling ratios near a twofold volume increase, the droplets retain structural stability and undergo partial polymerization. A water-soluble thermal radical initiator polymerizes the droplets from the surface inward, forming an elastic shell. Upon cooling, the internal volume contracts due to micelle release, and the mismatch between the shrinking interior and polymerized shell induces buckling. This controlled collapse yields a reproducible library of anisotropic colloids, including bowls, crumpled shells, and wrinkled spheres. The final morphology is governed by polymerization time and internal polymer distribution. The colloids remain elastic and can undergo further shape transformations when re-exposed to micelles at elevated temperatures. New lobes or protrusions form on the particle surface, with final geometry influenced by the initial morphology. The process is reversible across multiple thermal cycles and can be finely tuned through polymer concentration and thermal history, enabling precise control over particle geometry.
At the collective level, these shape-shifting colloids reorganize through geometry-dependent interactions and the generation of polymer concentration gradients. Changes in particle shape modulate interparticle packing and organization, leading to transitions from disordered to ordered states in dense suspensions. We quantify these structural changes using optical microscopy and hexatic bond order analysis, which reveal how local symmetry and packing evolve with particle shape. During deswelling, polymer release generates concentration gradients in the surrounding medium, driving directional motion and promoting long-range assembly.
By integrating shape evolution and polymer concentration gradients into colloidal design, we establish a framework for developing programmable, reconfigurable materials that respond dynamically to their environment. The coupling of adaptability with non-equilibrium interactions provides new opportunities for responsive coatings, adaptive suspensions, and functional materials with applications across physical and biological disciplines.