(Nanowerk Spotlight) Tiny plastic particles from decorative glitter infiltrate water systems and soil worldwide, adding to the growing crisis of microplastic pollution. These shimmering specks, smaller than five millimeters, persist in the environment for decades. While manufacturers have attempted to create biodegradable alternatives, they’ve struggled to replicate the uniform size, shape, and vibrant colors that make conventional plastic glitter so appealing for use in cosmetics, crafts, and industrial applications.
Scientists at the University of Chinese Academy of Sciences have now created biodegradable glitter that matches the visual properties of its plastic counterpart. Their manufacturing technique, detailed in Advanced Functional Materials (“All-Cellulose-Based Photonic Glitters”), transforms cellulose—the main component of plant cell walls—into precisely controlled, color-shifting particles.
The researchers focused on cellulose nanocrystals (CNCs), microscopic rod-shaped particles extracted from natural cellulose. These nanocrystals naturally stack themselves into spiral structures that create color through light interaction rather than pigments or dyes. Previous attempts to harness this property for glitter production yielded irregular particles with inconsistent coloring, but the new manufacturing process solves this through precise control over particle formation.
Schematic illustration of the a) fabrication process of CNC microdiscs and b) drying process of the CNC microdroplets. c) Photographs of the I) blue, II) green, and III) red CNC microdiscs generated by S1CNC, S2CNC, and S3CNC suspensions and dried on EC films with a contact angle of 6°. The electrospray process has a flow rate of 0.24 mL h−1 and a high voltage of 20 kV. The scale bar is 1 cm. (Image: Reprinted from DOI:10.1002/adfm.202423210, CC BY)
The technique begins with a water-based suspension of CNCs sprayed through an electrically charged needle. This creates uniform microscopic droplets that land on a specially prepared surface—a film of ethyl cellulose coated with silicone oil. The researchers discovered that treating this film with plasma changes how droplets spread on its surface, critically affecting the final particle shape and color.
By adjusting the film’s surface properties until droplets spread at a precise six-degree angle, the team produced flat, disc-shaped particles that maintain their shape and color consistency. Additionally, flow rate and voltage adjustments during the electrospray process fine-tune droplet size, ensuring precise control over the final particle diameter. The process allows precise size control—particles can range from 288 to 978 micrometers in diameter, adjusted by changing the spray’s flow rate and electrical charge.
The technology creates red, green, and blue glitter without additional colorants. Instead, different colors emerge by adjusting ultrasonication energy input, which modifies the arrangement of nanocrystals in suspension. This self-assembly creates structural color—the same phenomenon that gives morpho butterflies their brilliant blue wings.
The manufacturing process emphasizes sustainability beyond just the final product. The silicone oil used during production can be recovered and reused, as can the ethanol used to separate finished particles from their backing film. Additionally, the ethyl cellulose films themselves can be dissolved and reused, further minimizing waste. The resulting glitter maintains its appearance under various environmental conditions, including different lighting, humidity levels, and temperatures.
Testing revealed practical applications across multiple industries. The particles work well in nail polish and create distinctive patterns useful for anti-counterfeiting measures. Unlike previous CNC-based glitters that struggled with irregularity and poor coloration, this method produces uniform, vibrant particles suitable for both decorative and security applications. Safety testing showed high biocompatibility—cells exposed to high concentrations of the particles maintained 86% viability after 48 hours.
a) Photographs of I) blue-colored, II) green-colored, and III) red-colored CNC microdiscs suspended in ethyl cinnamate. Photographs of PDMS embedded with CNC microdiscs, taken by rotating the camera at fixed illumination and viewing angle of b) 20°, c) 40°, and d) 60°. The scale bar is 1 cm. e) Photographs of artificial nails, from left to right, coated with transparent nail polish, transparent nail polish embedded with CNC glitters, and black nail polish embedded with CNC glitters. f) Schematic illustration of the preparation of CNC pattern by using a designed mask and the photographs of a Chinese character “wood” character. The electrospray process had a flow rate of 0.24 mL h−1 and a high voltage of 20 kV. All the CNC microdiscs were dried on P3EC films with a contact angle of 6°. (Image: Reprinted from DOI:10.1002/adfm.202423210, CC BY)
This advance demonstrates how precisely controlled manufacturing can transform sustainable materials into high-performance products. The technology offers a path to eliminate an entire category of microplastic pollution while maintaining the visual properties that make glitter useful in applications from cosmetics to security features.
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