Multiresponsive Elastic Colloidal Crystals for Reversible Structural Color Patterns

Multiresponsive elastic poly(methyl methacrylate-butyl acrylate) (P(MMA-BA)) copolymer nanoparticles with controlled sizes are fabricated through a one-step method, which further serve as building blocks for the construction of multiresponsive films via self-assembly. Taking advantage of the relatively low glass transition temperature and the core–shell structure of the copolymer nanoparticles, they possess the capacity to partially deform and fuse at room temperature under dry status, eventually resulting in the enhancement of the mechanical properties as well as the control of optical properties in the assembled ordered structures. The generated elastic films not only can control the concealment or exhibition of the designed color information, but also can rapidly respond to external stimuli such as the solvent, pH, and tensile force in a reversible fashion. These functional elastic copolymer nanoparticles have potential applications in dynamic color display, optical sensing, and anticounterfeiting.