Tunable mechanical properties of aroma microcapsules achieved via cellulose nanocrystals interfacial self-assembly...

Traditional methods for regulating microcapsules' mechanical properties are limited by a narrow adjustment range and complex processes, hindering their functional applications. This study proposes a new regulation strategy using the interfacial self-assembly of cellulose nanocrystals (CNC). A controllable interfacial layer was formed through the electrostatic interaction between sulfonated CNC and NH₂-PDMS-NH₂, combined with tannic acid/polydopamine co-deposition to prepare microcapsules. By adjusting the concentration of NH₂-PDMS-NH₂, CNC adsorption at the interface between limonene oil and CNC water was regulated, reducing the emulsion interfacial tension from 20.8 mN/m to 5.6 mN/m. This led to a decrease in droplet size and improved emulsion stability. The storage modulus increased from 134.1 Pa to 625.9 Pa. Atomic force microscopy showed that the interfacial film thickness reached 22.6 nm. The Young's modulus of the obtained microcapsules was tunable within the range of 263.5-1606.5 MPa, representing a substantial enhancement compared to traditional methods. Furthermore, in pressure response tests, significant differences in aroma release were achieved by modulating the mechanical properties of the microcapsules. This study provides a novel strategy for the regulation of mechanical properties of microcapsules and is expected to promote their application in fields such as daily chemical products.