Shear‐Induced Assembly of Liquid Colloidal Crystals for Large‐Scale Structural Coloration of Textiles

Abstract Photonic crystals (PCs) constructed from colloidal building blocks have attracted increasing attention because their brilliant structural colors may find broad applications in paints, sensors, displays, and security devices. However, producing high‐quality structural colors on flexible substrates such as textiles in an efficient and scalable manner remains a challenge. Here a robust and ultrafast approach to produce industrial‐scale colloidal PCs by the shear‐induced assembly of liquid colloidal crystals of polystyrene beads pre‐formed spontaneously over a critical volume fraction is demonstrated. The pre‐crystallization of colloidal crystals allows their efficient assembly into large‐scale PCs on flexible fabric substrates under shear force. Further, by programming the wettability of the fabric substrate with hydrophilic–hydrophobic regions, this shear‐based assembly strategy can conveniently generate pre‐designed patterns of complex structural colors. This assembly strategy brings structural coloration to flexible fabrics at a scale suitable for commercial applications; therefore, it holds the potential to revolutionize the coloration technology in the textile industry.