Vat Photopolymerization

Abstract

AbstractVat photopolymerization is an additive manufacturing process to build solid parts by leveraging photoinduced polymerization of liquid resins (i.e., a polymerization reaction triggered by irradiation). The chemical transformation of the monomers, oligomers, and/or prepolymers forming the resin (usually called vat) into polymers is in fact accompanied by a phase change from the liquid to the solid state. Vat photopolymerization includes a wide variety of processes and technologies, such as stereolithography (SLA), digital light processing (DLP), continuous liquid interface production (CLIP), and two-photon lithography (2PP). In all these techniques, the solid part is built layer by layer: the liquid resin fills a tank and its surface is selectively irradiated and cured; then the building platform is raised or lowered of a small increment to allow new liquid to flow forming another layer, which is cured by light and adjoins the previous one. Once the last layer is cured, the printed part is removed from the resin tank. As the polymer chemistry employed in vat photopolymerization is highly versatile, many innovations have been developed, and nowadays, complex multifunctional products with tailored performance can be printed, reaching high resolution and very low feature size, allowing their application in different fields. This chapter reviews vat photopolymerization technology and describes its chemistry, the different techniques (excluding 2PP, which is the focus of Chap. 3), and the materials employed.KeywordsVat photopolymerizationPhotocurable resinsUV curingStereolithographySLADigital light processingDLPContinuous liquid interface productionCLIP3D printing