LAUSR

Visualization and quantification of invisible lights, such as microwave, are significant for their safe use. In general, sensi-tizer material combined with transistor is used as electronic devices for the measurement. Here we developed thermo-responsive color-change hydrogel of poly(N-isopropylacrylamide) (PNIPAAm) crosslinked by layered organic composite based on polydiacetylene (PDA) for visualization and colorimetric quantification of microwave. The layered PDA in the PNIPAAm hydrogel showed the temperature-dependent gradual color change with heating. Irradiation of microwave in-duced the color change of PDA through heating of water in the hydrogel and subsequent volume shrinkage. Color of the gel was applied to visualize the temperature distribution with increasing irradiation time of microwave. Moreover, power of the irradiated microwave was quantified by time to the complete color change of the gel. The results indicate that the stimulus conversion process has potentials for development of a variety of imaging and quantification devices based on the layered PDA.