Temperature responsive self-assembled hydroxybutyl chitosan nanohydrogel based on homogeneous reaction for smart...

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Chitosan (CS) nanohydrogels offer versatile applications due to biodegradability and responsiveness.
• Current CS derivative synthesis often uses unstable, environmentally unfriendly heterogeneous systems.

Purpose of the Study:

• To develop a green, homogeneous synthesis for hydroxybutyl chitosan (HBC) nanohydrogels.
• To investigate the temperature-responsive phase transformation and potential applications of HBC nanohydrogels.

Main Methods:

• Synthesized hydroxybutyl chitosan (HBC) using a green homogeneous system (potassium hydroxide/urea).
• Investigated the phase transformation behavior of HBC in deionized water with temperature changes.
• Evaluated the stability and reusability of the resulting nanohydrogels over 50 cycles.
• Analyzed concentration and temperature-dependent UV absorption and visible light regulation.

Main Results:

• Achieved a stable, repeatable (over 50 cycles) temperature-responsive phase transformation of HBC from dissolved state to nanohydrogel state.
• Demonstrated concentration and temperature-dependent UV absorption and visible light regulation in HBC nanohydrogel solutions.
• The developed HBC nanohydrogels exhibited no coagulation after repeated cycles.

Conclusions:

• A novel, green, and homogeneous preparation method for chitosan-based temperature-responsive self-assembled nanohydrogels was established.
• Hydroxybutyl chitosan (HBC) nanohydrogels show significant potential for smart window applications due to their responsive optical properties.
• This work expands the application scope of chitosan-based nanohydrogels in various fields.