One-pot preparation of physical and chemical double-cross-linked nanocellulose/poly(deep eutectic solvent) conductive elastomers in acidic deep eutectic solvent (DES) system for 3D-printable information-storage expansion

3D-printable information-storage expansion materials can integrate multilevel optical information within one carrier, which requires higher requirements for their mechanical properties. Cellulose nanofiber (CNF) is an attractive candidate for enhancing the mechanical properties of composite materials. However, CNF composites generally increase stress at the expense of strain by physical compounding of CNF. Herein, a physical and chemical double-cross-linked (DC) network of cellulose nanofiber/poly(deep eutectic solvent)(CNF/PDES) conductive elastomers are prepared by introducing glycidyl methacrylate (GMA) through nanofibrillation, derivatization modification, and in-situ polymerization in the oxalic acid/choline chloride (OA/ChCl) DES system. The carboxylation modification of OA-CNF could provide active cross-linking sites, and derivatization modification of GMA was shortened from 4 to 0.5 h under the catalysis of ZnCl2. DC OA-CNF/PDES conductive elastomers were rapid polymerization within 30 s and significantly improved the stress and strain simultaneously (stress: 252.51 kPa to 417.53 kPa, strain: 262.29 % to 419.44 %), and excellent 3D printable accuracy and formability for information encryption, and information-storage expansion. Subsequently, we systematically compared the feasibility and difference of OA/ChCl, lactic acid/choline chloride (LA/ChCl), maleic acid/choline chloride (MA/ChCl), and propanedioic acid/choline chloride (PA/ChCl), and provide a promising route for 3D-printable high-performance flexible sensors and information-storage expansion under DES systems.