Thermally Tunable Hydrogels Displaying Angle-Independent Structural Colors

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Structural color arises from light interacting with ordered nanostructures.
• Developing materials with tunable, angle-independent structural color remains a challenge.
• Colloidal amorphous arrays offer a route to creating disordered yet functional nanostructures.

Purpose of the Study:

• To prepare thermally tunable hydrogels with angle-independent structural colors.
• To investigate the role of carbon black in achieving bright structural colors.
• To explore the temperature-dependent color-changing properties of these hydrogels.

Main Methods:

• Fabrication of porous hydrogels using colloidal amorphous array templates.
• Incorporation of a small amount of carbon black (CB) into the hydrogel matrix.
• Characterization of structural colors and their dependence on temperature and viewing angle.

Main Results:

• Hydrogels without CB appeared white, while those with CB exhibited bright structural colors.
• The structural colors were angle-independent under diffusive lighting.
• The hydrogels demonstrated rapid, reversible color changes with varying water temperature.

Conclusions:

• Thermally tunable hydrogels with angle-independent structural colors can be prepared using colloidal amorphous arrays and carbon black.
• The isotropic nanostructure generated from colloidal amorphous arrays is key to angle independence.
• These materials hold promise for applications in temperature sensing and dynamic displays.