Figure 4
From: Reconstruction of Dynamic and Reversible Color Change using Reflectin Protein
Optical characterization of the dynamic color changing of Reflectin protein. (a–j) Spin-coated films of Reflectin (SoRef2) incubated with (Reflectin/Imidazole) and without (Reflectin) imidazole. Reflectin/Imidazole film (the upper panel, a–e) exhibited dynamic color changes (stage 1 to stage 5) from colorless to white (indicated by white arrows) followed by blue (indicated by blue arrows) gradually from the edge to the center of the film during the water evaporation process, whereas Reflectin film without aromatic molecules (the lower panel, f–j) remained colorless. (k) Normalized scattered reflectance spectra of Reflectin/Imidazole film during the color changing process, corresponding to five stages in (a–e) measured using the setup reported in Fig. 2m. (l) Transmittance spectra of Reflectin/Imidazole film during the color changing process, corresponding to five stages in (a–e) measured using the setup reported in Fig. 2i. (m–v) The reversibility of dynamic color change of Reflectin/Imidazole film. Note that the right half of the film was covered with a slide glass to protect from the hydration and dehydration cycles. (m) Blue dried Reflectin/Imidazole film. (n) Hydration of left half of Reflectin/Imidazole film by water mist spray from an ultrasonic humidifier. (o) Left half of Reflectin/Imidazole film turned into colorless gradually along with the hydration process. (p) Light blue appeared at the left corner as dehydration started. (q) Light blue progressed along with the dehydration of the left half of Reflectin/Imidazole film. (r) Left half of Reflectin/Imidazole film turned into blue when dehydration process completed. (s) Re-hydration of left half of Reflectin/Imidazole film in (r) by water mist spray. (t) Left half of Reflectin/Imidazole film turned into colorless again when hydration process completed. (u) Light blue appeared at the left top corner as dehydration started. (v) Left half of Reflectin/Imidazole film turned into blue again when dehydration process completed. The scale bars represent 2 mm.
