Spontaneously assembled cellulose nanocrystal structural color films with tunable properties

Area of Science:

• Materials Science
• Nanotechnology
• Biomaterials

Background:

• Cellulose nanocrystals (CNC) exhibit cholesteric liquid crystal properties enabling self-assembly into layered structures.
• These structures produce structural coloration, offering potential for environmentally friendly pigments.

Purpose of the Study:

• To fabricate vibrantly colored CNC films using bamboo-based CNC and hydroxypropyl cellulose (HPC).
• To regulate the pitch of layered structures for tunable structural coloration.
• To optimize film properties through controlled self-assembly.

Main Methods:

• Layer-by-layer self-assembly of bamboo-derived CNC.
• Incorporation of HPC to modulate the pitch of CNC structures.
• Varying CNC/HPC ratios (100/0, 92/8, 87/13, 82/18) to achieve different colors.
• Adjusting equilibrium time and solvent composition to enhance crystalline aggregate arrangement.

Main Results:

• Fabrication of CNC films with colors ranging from blue to red by altering CNC/HPC ratios.
• Achieved uniform colors through facilitated directional arrangement of crystalline aggregates.
• Optimized optical and mechanical properties of the resulting CNC films.

Conclusions:

• Bamboo-based CNC and HPC are effective for creating tunable, structurally colored films.
• Controlled self-assembly parameters optimize film uniformity and performance.
• Developed eco-friendly pigments with potential applications in various industries.