On March 30, 2025, researchers from the Autonomous University of Barcelona (UAB) announced a dual-light-controlled polymerization process that can increase 3D printing resolution to the submicron level.
The new method was published in Advanced Functional Materials in a paper titled "Antagonistic Two-Color Control of Polymer Network Formation." The paper introduces a dual-wavelength control method that can significantly improve precision and material control.
Paper link: https://doi.org/10.1002/adfm.202415431
Conventional 3D printing methods typically use a single light source to cure polymer materials. These techniques have limited spatial resolution due to diffusion of reactants and the natural limits of light diffraction. In contrast, the new system at UAB uses two opposing light sources (ultraviolet and red) to precisely control where solid materials form. One beam of light activates polymerization, while the other stops it. This interaction ensures that material forms only where the UV light alone shines. When the two beams overlap, the curing reaction stops, providing unprecedented spatial control.
The breakthrough is the result of a collaboration between chemist Jody Hernando of the University of Alabama at Birmingham and Professor Christopher Barna-Kovolik of Queensland University of Technology in Australia. The research team developed a photochemical reaction based on an oxo-Diels-Alder cycloaddition. The chemical reaction is based on a specially made prepolymer activated by ultraviolet light and a curing agent that switches its reactivity depending on the type of light.
Unlike conventional systems, the new method uses photoantagonism - a new concept in which one color initiates curing and another inhibits it. This system enables scientists to customize 3D structures with high spatial precision. This breakthrough directly addresses the long-standing problems of low resolution and imprecise boundaries in additive manufacturing.
Schematic diagram introduces an antagonistic two-color photochemical reaction strategy to control the formation of polymer networks between photocaged dienes and photoswitchable dienophiles by utilizing light-modulated oxo-Diels-Alder reactions.
Importantly, this approach also reduces material waste and increases the overall efficiency of the 3D printing setup. Due to targeted activation, only the necessary areas are cured, streamlining the process and saving resources.
In laboratory tests, the research team successfully produced solid polymer materials with clear geometric shapes with a resolution of less than 1 micron. Potential applications cover a variety of industries, from microelectronics and medical devices to photonics and micromechanical parts. Hernando said: "We are now working towards sub-micron accuracy, which marks a major step forward in 3D printing technology."
Timing and accuracy are critical in additive manufacturing. Many current systems suffer from slow processing times and fuzzy print lines due to imprecise polymerization zones. New light-based reactions speed up curing while improving clarity. These advantages could pave the way for ultra-fast prototyping and higher-quality end products.
