Tetrahedral, Octahedral, and Triangular Dipyramidal Microgel Clusters with Thermosensitivity Fabricated from Binary Colloidal Crystals Template and Thiol–Ene Reaction

A template-based strategy to fabricate soft colloidal clusters with distinct symmetries of tetrahedra, octahedra, and triangular dipyramid is described. We use binary microgel colloidal crystals as a template, in which the large microgels with surface thiol groups are arranged into a close-packed lattice and a few small microgels with surface vinyl groups occupy the tetrahedral or octahedral interstitial sites, and then immobilize the structure via in situ thiol–ene reaction under UV irradiation. Both 2D cross sections and reconstructed 3D morphology of these clusters are clearly characterized by confocal laser scanning microscopy. The formation mechanism of microgel clusters is discussed, which is closely related to the microgel soft properties, size ratio, and colloidal crystal packing structure. The resulting clusters inherit the thermosensitivity and defects tolerance of poly­(N-isopropylacrylamide) (PNIPAM) microgel, which would facilitate their self-assembly into more complex structures.