The Polymer Society of Korea

Abstract

Microgels are soft materials with tunable rheology, suited for applications such as 3D printing, drug delivery, and coatings. However, balancing printability and structural stability remains a challenge. Here, we explore nanoparticle aggregation as a reversible physical cross-linking mechanism in silica-Carbopol microgel composites. Silica nanoparticles aggregate at low pH and disperse at high pH due to surface charge changes, enabling reversible control of elasticity and yield stress. Structural transitions are characterized using SAXS, NMR, and recovery rheology. We further show thatt aggregation kinetics can be tuned via particle size, temperature, and concentrations. Our approach provides a pathway to create microgel composites with reversible mechanical properties, opening new possibilities for advanced ink formulations and sustainable material applications.