Kyoto University unveils structural-white polymer as pigment-free alternative

Researchers at Kyoto University's ICEMS, working with Donghua University, have developed Deep Foam Photolithography (DFP), a light-based process that makes polymers such as PET white and water-repellent through a porous internal structure rather than added titanium dioxide pigment or PFAS coatings. The work has been demonstrated in six polymer types and published in Nature, and remains at laboratory stage. Lead author Easan Sivaniah says the effect on recyclability has not been tested and that direct comparisons under realistic packaging conditions come next.

Why this mattersA pigment-free route to whiteness and water repellency could reduce packaging reliance on titanium dioxide and PFAS as both face tightening regulatory scrutiny.

• DFP uses light and a mild solvent to create a porous structure that scatters light for whiteness, rather than adding titanium dioxide pigment or PFAS coatings
• Demonstrated in six polymers including PET, polystyrene, polycarbonate, cellulose triacetate, polysulfone and polymethyl methacrylate
• Research led by Easan Sivaniah at Kyoto University's ICEMS with Donghua University, China, published in Nature
• The EU banned titanium dioxide as a food additive in 2022
• Researchers say effects on recyclability and microplastic generation have not yet been tested
• Sivaniah says the next step is direct comparison with titanium dioxide under realistic packaging conditions

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