Deep-Eutectic-Solvent-Containing Photocurable Systems: Component Identity, Speciation, Water, Polymerisation and Leaching

Deep eutectic solvents (DESs) can reduce viscosity, introduce hydrogen-bonding interactions and provide ionic or chemical functionality in photocurable systems. Their defining feature is not simply a low melting point but a composition-dependent liquid state created by strong interactions between components, often a hydrogen-bond donor and acceptor. Water, impurities and polymerisation can change that state. A 2023 study demonstrated DES-based photocurable resins compatible with commercial LCD vat photopolymerisation, showing that the concept can move beyond solution chemistry into printed networks. [1] This review focuses on the engineering consequences: exact component identity and molar ratio, water content, phase behaviour, cure kinetics, extractable fraction, mechanical response and environmental stability must be recorded together. It distinguishes a true DES-containing network from an ordinary monomer mixture labelled after its feedstock and proposes qualification tests that prevent viscosity or strength improvements from masking leaching, water sensitivity or cure-state changes. ER-415.