Multifunctional photonic cellulose inks with tunable structural colors

• Hydroxypropyl cellulose photonic ink with tunable structural colors is developed • The structural colors of cellulose photonic ink are stimuli-responsive • The photonic ink shows applications in information encryption and 3D-printing Structural color materials with stimuli-responsive properties are valuable in diverse fields. Attempts in this area focus on developing a convenient strategy for tailoring multifunctional and biocompatible structural color materials. In this paper, we propose multifunctional photonic cellulose inks with tunable structural colors and verified their applications in sensing, encryption, and printing. Hydroxypropyl cellulose after chemical grafting shows tunable structural colors in response to temperature and mechanics stimuli, together with in situ polymerization capacity to immobilize the helical nanostructures. Through selective polymerizing the assembled cellulosic liquid crystals, the structural color of polymerized region could be immobilized while the unpolymerized region is able to change color upon cooling and heating, thus realizing the information encryption and decryption. In addition, the intrinsic high viscosity of cellulosic liquid crystal solution makes it suitable choice for printing. Taking advantage of the cellulose ink and ultraviolet irradiation, different patterns including letters, 2D monochromatic patterns, 2D dichromatic patterns and 3D patterns could be achieved. The results indicate that our photopolymerizable cellulose-based structural color materials may find broad applications in optical displaying, sensing and other biomedical fields.