Structuring Liquids Through the Tailored Progressive Directed Assembly of Lignin Nanoparticles at the Liquid–Liquid Interface

Abstract Emerging structured liquids have a lot of potential for transport channels in the liquid state because of their mobility, reconfigurability, and substance exchange. However, achieving stable drug delivery channels by precisely managing the structured liquid network still faces significant challenges. The design of nanoparticles is inspired by the tentacles of squid that deformed arbitrarily and exchanged substances with the external environment. A strategy to effectively reduce the energy barrier between liquid–liquid interfaces and amphiphilic lignin nanoparticles (LNPs) with interfacial activities through progressive directed assembly is proposed to achieve stable, reconfigurable encapsulation of liquids. An anisotropic nanoparticle structure consisting of a mixture of hydrophilic and lipophilic sites distributed on a spherical surface is designed to improve adsorption stability at the liquid–liquid interface. The surface polarity and spherical nanoscale dimensions of LNPs are regulated by modulating the phenolic hydroxyl content and molecular weight of lignin. Furthermore, a regulatory pathway between the molecular structure of lignin and the interfacial properties of LNPs is constructed. This strategy yielded more stable equilibrium sites for LNPs interfacial anchoring, resulting in highly integrated and stable structured liquids. This opens a wider range of possibilities for the interfacial design of encapsulation materials, drug delivery channels, and microreactors.