Vat photopolymerization is a 3D printing process where a liquid resin that reacts to light is poured into a container and then solidified layer by layer using a laser or ultraviolet light to form a 3D shape. However, this approach is limited because it only works with light-sensitive polymers, which restricts the types of materials that can be produced.
Some 3D printing techniques have tried to overcome this by transforming printed polymers into metals or ceramics. Yet, according to Daryl Yee, head of the Laboratory for the Chemistry of Materials and Manufacturing at EPFL’s School of Engineering, these materials often fall short in quality.
“These materials tend to be porous, which significantly reduces their strength, and the parts suffer from excessive shrinkage, which causes warping,” he says.
To solve these challenges, Yee and his team developed an innovative method described in their paper published in Advanced Materials. Instead of curing a resin that already contains metal compounds, the researchers begin by 3D printing a framework made from a simple, water-based gel called a hydrogel. This blank structure is then soaked in metal salts, which are chemically transformed into tiny metal-containing nanoparticles that spread throughout the gel. The process can be repeated several times to increase the concentration of metal within the material.
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