Monolithic Spiropyran-Based Porous Polysilsesquioxanes with Stimulus-Responsive Properties

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Spiropyrans are key dynamic components in stimulus-responsive materials.
• Covalent incorporation into silsesquioxane frameworks remains largely unexplored.
• Existing methods often restrict spiropyran's functional freedom.

Purpose of the Study:

• To covalently embed spiropyran into silsesquioxane bulk materials.
• To investigate the stimulus-responsive properties of the resulting dynamic materials.
• To explore applications in surface wettability modification.

Main Methods:

• A two-step co-condensation sol-gel approach was employed.
• Silylated spiropyran derivative was incorporated into ultralight silsesquioxane frameworks.
• UV-vis spectroscopy and contact angle measurements were used for characterization.

Main Results:

• Successful covalent incorporation of spiropyran without loss of function.
• Demonstrated reversible color changes triggered by UV/visible light and pH.
• Significant alteration of surface polarity and water wettability (contact angle change from 146° to 100°).
• Materials exhibit high surface areas, low densities, and high porosity (up to 84%).

Conclusions:

• The developed method enables the creation of novel dynamic silsesquioxane-based materials.
• These materials offer tunable surface properties via external stimuli.
• The findings open avenues for advanced functional materials in various applications.