Responsive Smart Windows Enabled by the Azobenzene Copolymer Brush with Photothermal Effect

Area of Science:

• Materials Science
• Polymer Chemistry
• Optoelectronics

Background:

• Liquid crystalline polymers (LCPs) offer unique optical and responsive properties.
• Azobenzene derivatives are known for their photoresponsive behavior.
• Polymer brushes can modify surface properties and induce molecular alignment.

Purpose of the Study:

• To synthesize and characterize a novel azobenzene side chain liquid crystalline copolymer (MAzo-co-GMA).
• To investigate the formation of polymer brushes from MAzo-co-GMA and their effect on liquid crystal alignment.
• To fabricate and evaluate a polymer-stabilized liquid crystal (PSLC) smart window utilizing these polymer brushes.

Main Methods:

• Copolymerization of MAzo and GMA monomers.
• Thermal annealing to form polymer brushes on a substrate.
• Fabrication of a liquid crystal cell with the polymer brush as the substrate.
• Characterization of the PSLC smart window's optical states and response times.

Main Results:

• Successful synthesis of MAzo-co-GMA copolymer.
• Formation of stabilized polymer brushes that induce liquid crystal alignment.
• Demonstration of a PSLC smart window with tunable transparency (transparent SmA* phase, opaque N* phase) via UV light or heat.
• Achieved good reversibility and stability in the smart window's performance.

Conclusions:

• The MAzo-co-GMA copolymer effectively forms photo- and thermo-responsive polymer brushes.
• The developed PSLC smart window exhibits controllable optical switching.
• This technology holds promise for energy-saving applications in smart windows and other devices.