The challenge of creating a photopolymer resin capable of polymerization at one range of wavelengths with the added capability of depolymerization at a different range of wavelengths is an ongoing work in polymer formulation development. The photo-selectivity of both processes allows for deliberate and spatially accurate control for adding and removing polymer materials. This has great relevance to the development of new photoresist technology as well as advancing additive manufacturing where subtractive capabilities are of growing importance.
LLNL inventors have developed a photopolymer resin formulation that consists of a (1) pH labile monomers, (2) a photoinitiator, (3) a photoacid or photobase generator, (4) other additives including, reactive and unreactive diluents, and pH stabilizers. When exposed to radiation in a specific wavelength region, component 2 initiates polymerization with 1 to form a pH sensitive network. Subsequent degradation of the network can then be initiated via the activation of component 3 by radiation of a second wavelength region. The combination of the components enables the resin to be polymerized and degraded via photo-enabled processes using different wavelengths of light (UV and visible). This dual photo functionality at different wavelengths of light is one of the key innovations of this polymer formulation.
Current stage of technology development: TRL-3
- Uses visible light to trigger photopolymerization.
- Uses UV light to trigger photodegradation to liquid byproducts.
- Liquid byproducts should be more easily reused as chemical feedstock.
- The degradation mechanism of the 3D printed polymer system relies on chemical attack of polymer chain via acid or base chemistry induced via UV light rather than changes to polymer functionalities to induce solubility differences.
Recyclable plastics, degradable polymer mold, dynamic 3D printed polymer casts, photoresists
