Construction of Steady Amorphous Colloidal Array Patterns via Infiltration-Driven Assembly of Core–Shell Microparticles followed by Short-Time Heating

Although core-shell microparticles with a hard core and soft shell are often used to fabricate photonic crystal films, they are rarely applied to construct steady amorphous colloidal array (ACA) patterns. In this work, a series of monodisperse core-shell microparticles with a polystyrene (PS) core and poly(methyl methacrylate-butyl acrylate) (P(MMA-BA)) shell have been successfully synthesized, and the glass transition temperatures (T_g) of the shell layer have been well regulated. The synthesized core-shell microparticles were then used to fabricate ACA patterns via a convenient infiltration-driven assembly method. The results showed that the T_g of the shell significantly affected the microstructure of the amorphous colloidal arrays (ACAs). During the assembly process, the microparticles quickly contacted each other and the lower-T_g shells could merge with each other to form a continuous film. In this situation, the PS core was embedded and ranked in the P(MMA-BA) film, and both the refractive index contrast and order degree of the colloidal array became relatively low, resulting in a poor structural color. However, when the T_g of the shell layer was moderately high, a short-range ordered array was prepared via infiltration-driven assembly, thereby displaying a bright structural color. More importantly, the shell layers could merge with each other to some extent after short-time heating, resulting in fine mechanical stability. In brief, this study provides a facile and environmental approach to construct steady ACA patterns, which is promising in printing and painting industries.