Three-Dimensional Printed Shape Memory Gels Based on a Structured Disperse System with Hydrophobic Cellulose Nanofibers

Abstract

Inks for 3D printing were prepared by dispersing bacterial cellulose nanofibers (CNF) functionalized with methacrylate groups in a polymerizable deep eutectic solvent (DES) based on choline chloride and acrylic acid with water as a cosolvent. After 3D printing and UV-curing, the double-network composite gel consisting of chemically and physically crosslinked structures composed from sub-networks of modified CNF and polymerized DES, respectively, was formed. The rheological properties of inks, as well as mechanical and shape memory properties of the 3D-printed gels, were investigated in dynamic and static modes. It was shown that the optimal amount of water allows improvement of the mechanical properties of the composite gel due to the formation of closer contacts between the modified CNF. The addition of 12 wt% water results in an increase in strength and ultimate elongation to 11.9 MPa and 300%, respectively, in comparison with 5.5 MPa and 100% for an anhydrous system. At the same time, the best shape memory properties were found for an anhydrous system: shape fixation and recovery coefficients were 80.0 and 95.8%, respectively.

Natural Oleanolic Acid-Tailored Eutectogels Featuring Multienvironment Shape Memory Performance

“…In 2023, Liu and co-workers first reported a thermoresponsive shape memory eutectogel by polymerization of DESs ( N -ayanomethyl cerylamide/lithium bis­(trifluoromethane)), which showed complete shape fixation/recovery and fast recovery (<6 s). Smirnov and co-workers developed inks for 3D printing by dispersing functionalized bacterial cellulose nanofibers in polymerizable DES (choline chloride/acrylic acid/water) to construct shape memory eutectogels. These newly reported studies open an avenue for the development of shape memory eutectogels, but they are still in their infancy and need to be further explored.…”