Cellulose in situ formation of three primary nanoparticles for polymer scalable colors

Polymer coloration technology has been receiving increasing attention in different fields including electronic packaging, artificial skin and 3D printing. Herein, we report a new strategy utilizing three primary nanocomposites (cellulose@Fe 3 O 4 , cellulose@FeOOH and cellulose@PB) as unique coloring components for scalable colored polymer-based composites. Taking the epoxy resin as polymer matrix for example, the as-made polymer-based composites present different colors, including red/yellow/blue colors and many spectral colors achieved by mixing the three primary nanocomposites. The nanocomposites act not only as the primary nanopigments, but also as the connected bridge to tightly stick polymer matrix through strong chemical bonding, respectively. In addition, the colored polymer-based composites show excellent opacity and UV protection. Our work offers a facile coloration approach for arbitrary colors over the whole visible spectra by mixing three primary nanocomposites at different ratios in the polymer field. With bright, uniform, and ratio-dependent color, we showcase three typical polymers to demonstrate the versatility of coloring strategy. Graphical abstract We have developed a simple strategy to fabricate cellulose in situ deposited three primary nanocomposites. Taking the polymer matrix for example, arbitrary color can be created by mixing them into polymer at different ratios over the whole visible spectra by dispersing three primary nanocomposites.