As we all know, 3D printing is pretty cool. Typically it works similarly to the old inkjet (yeah, you guys remember those?) printers. Layers of polymer are printed while hot, and polymerize with the next layer that is printed on top of the sheet. Additionally, different materials can be used- the other day I heard of a ChefJet that uses sugar as the polymer to literally 3D print cakes… crazy stuff! However, sometimes this polymerization can be too slow- I remember when using an inkjet 3D printer at MIT, it took 2 hours to print a relatively simple mug. So is there another solution?
Turns out, yes there is! Using a technology called CLIP- continuous liquid interface polymerization, Joseph Desimone from UNC is really making waves in the 3D printing business. Notice that I said liquid- this uses interfacial polymerization, which is a faster chemical reaction than using inkjet printing. Light activates the monomer radical to start the reaction, and oxygen acts as the inhibitor to the reaction.
A quick aside (and chemistry lesson): polymerization occurs in three phases- initiation, propagation, and termination. In initiation, a monomer is activated (by light, heat, or some other initiator) to become a free radical. In propagation, an activated monomer combines with an unactivated monomer to extend the chain- now called a polymer. This chain continues to grow as more and more monomer is used up. Finally, in the termination step, two radicals combine to terminate the polymer growth and form the final product. Here light is an initiator and oxygen is a terminator.
As you can imagine, usually these reactions occur separately, and you wouldn’t want to oversaturate a monomer solution with light or oxygen- so a continuous system seems implausible. CLIP solves this problem by creating a micron-sized thin layer that is a ‘dead zone’, below which light grows the polymer and above which oxygen quenches the reaction. The result? Enjoy: Joseph Desimone- Carbon 3D