Ultrafast and Irreversibly Thermochromic SiO2-PC/PEG Double Layer for Green Thermal Printing

Traditional thermochromic photonic crystal (PC) usually has a slow and reversible thermal response, which limits its application in thermal printing. Here, the authors develop a thermochromic SiO2-PC/PEG double layer structure with a responding time of milliseconds for fast thermal printing. Controlled by the print-head, the polyethylene glycol (PEG) melts, infiltrates, and solidifies within the interparticle voids, which instantly and irreversibly changes the refractive index and produces the PC pattern. Multicolor printing can be realized by tuning the size and type of colloidal particles. Resolution as high as 300 DPI is achieved to print the high-resolution patterns and then the grayscale patterns based on the control of pixel densities. Different from fiber thermal paper, the SiO2-PC/PEG film has no toxic bisphenol A and possesses superior light stability for keeping the images longer. It is fully compatible with the commercial printer, which provides a mature solution for fast and convenient preparation of PC patterns.

Automated summary

The authors developed a thermochromic SiO2-PC/PEG double layer structure with a responding time of milliseconds for fast thermal printing, which can achieve multicolor printing by tuning the size and type of colloidal particles. High-resolution and grayscale patterns can be printed based on the control of pixel densities.