Mechanically Responsive Circularly Polarized Luminescence from Cellulose-Nanocrystal-Based Shape-Memory Polymers.

Area of Science:

• Materials Science
• Polymer Chemistry
• Optoelectronics

Background:

• Stimulus-responsive materials with circularly polarized luminescence (CPL) are crucial for chiral sensors and smart displays.
• Controlling CPL properties remains challenging due to difficulties in regulating chiral structures.

Purpose of the Study:

• To demonstrate mechanically responsive CPL using cellulose nanocrystal shape-memory polymers (CNC-SMPs).
• To achieve fine control over CPL emission characteristics through material manipulation.

Main Methods:

• Fabrication of luminescent CNC-SMPs incorporating cellulose nanocrystal (CNC) chiral nematic organization.
• Manipulation of the photonic bandgap and luminescence wavelengths via thermal and mechanical stimuli.
• Characterization of CPL properties, including dissymmetry factors (g_lum).

Main Results:

• Achieved precise control of CPL emission with tunable wavelengths and high dissymmetry factors (g_lum).
• Demonstrated reversible switching of CPL emission via hot-pressing and thermal recovery.
• Exhibited pressure-responsive CPL with tunable g_lum values linked to photonic bandgap changes.
• Created colorimetric and CPL-active patterns through imprinting techniques.

Conclusions:

• Cellulose nanocrystal shape-memory polymers (CNC-SMPs) offer a novel platform for mechanically responsive CPL.
• This approach enables the fabrication of smart CPL systems using sustainable biomaterials.
• The study provides a new pathway for developing advanced chiral sensors and smart displays.