Cellulose nanocrystals (CNCs) are rod-like nanoparticles derived from renewable biomass and have recently gained attention as sustainable hydrocolloids for food and functional material applications. Achieving sol–gel transition and viscoelastic control even at lower solid contents would expand their potential for environmentally friendly formulation design.

In this study, electrophoretic mobility was measured to examine the charging behavior of CNC particles under various pH and electrolyte conditions. Furthermore, we systematically investigated how electrolyte concentration, particle concentration, and resting time influence the sol–gel state of semi-dilute aqueous CNC suspensions. Gelation behavior was evaluated by a simple vial inversion test, and viscoelastic properties were characterized using small- and large-amplitude oscillatory shear measurements.

The electrophoretic mobility results showed that CNC particles retained a negative charge nearly independent of pH, indicating stable surface potential and electrostatic repulsion over a wide pH range. Gelation occurred within a limited window of electrolyte concentrations and became more pronounced with increasing CNC concentration and resting time. The appearance of a finite elastic modulus confirmed the formation of a gel network. The dependence on electrolyte concentration suggests that orientation-dependent aggregation among charged rod-like particles governs the network structure. These findings provide fundamental insights into the design of sustainable, bio-based hydrocolloid gels with tunable mechanical properties