Single-Vat Multimaterial Vat Photopolymerisation by Photochemical Addressing: Wavelength Selectivity, Dose Encoding, Reaction Orthogonality and Crosstalk

Multimaterial vat photopolymerisation can encode distinct polymer states within one liquid formulation by changing wavelength, dose or the photochemical pathway activated at each location. Direct primary studies demonstrate three relevant strategies: wavelength-selective radical and cationic curing from a multicomponent resin, grayscale control of local conversion and mechanical state in a single-cure resin, and dose-triggered switching between polymerisation mechanisms reported through a photobuffer-mediated system. A recent hybrid epoxy-acrylate study further reports dual-projection fabrication of hard and soft domains from one resin. These demonstrations do not by themselves establish robust material identity, reaction orthogonality or transferable process windows. ER-197 therefore treats multimaterial addressing as a classification and verification problem. It defines the commanded optical state, measured delivered excitation, reaction response, final material state and spatial location as separate quantities. A selectivity matrix records intended and unintended responses for every command-state pair. Qualification requires chemical evidence of reaction allocation, spatial measurement of crosstalk, property verification at homogeneous states and interfaces, and challenge conditions near decision boundaries. The method is intentionally non-prescriptive: no initiator identity, concentration, absorber loading, inhibitor level, exposure threshold or resin composition is proposed. The result is a defensible way to determine whether a one-vat or one-pot system is genuinely multimaterial rather than merely dose-varied or incompletely cured.