Crystallization induced dual networks regulate nonlinear rheology and 3D printability of CNC capillary oleogels

Capillary oleogels are promising materials for 3D printing, yet their printability is limited by the fragile nature of capillary-bridged networks. Here, dual networks were formed by incorporating beeswax crystals into cellulose nanocrystal (CNC) capillary oleogels, generating interconnected capillary and crystallization-induced networks. Microstructural analyses showed that beeswax crystallization promoted CNC aggregation and altered network architecture through physical interactions. Stability analysis revealed that beeswax incorporation improved the oil-holding capacity from 79.28% to 97.07%, while maintaining nearly complete oil retention after repeated freeze-thaw and melt-recrystallization cycles. Rheological measurements demonstrated a non-monotonic effect of beeswax concentration, with low levels weakening capillary connectivity and higher levels forming a reinforcing crystalline network. Nonlinear rheology analysis revealed increasingly constrained intracycle structural evolution in stronger networks. These rheological characteristics translated into improved extrusion behavior and shape fidelity during 3D printing. This work establishes a structure-rheology-printability framework for rational design of oleogel-based printing materials.