Unravelling the Hydration Barrier of Lignin Oleate Nanoparticles for Acid‐ and Base‐Catalyzed Functionalization in Dispersion State

Abstract

Lignin nanoparticles (LNPs) are promising renewable nanomaterials with applications ranging from biomedicine to water purification. However, the instability of LNPs under acidic and basic conditions severely limits their functionalization for improved performance. Here, we show that controlling the degree of esterification can significantly improve the stability of lignin oleate nanoparticles (OLNPs) in acidic and basic aqueous dispersions. The high stability of OLNPs is attributed to the alkyl chains accumulated in the shell of the particle, which delays protonation/deprotonation of carboxylic acid and phenolic hydroxyl groups. Owing to the enhanced stability, acid‐ and base‐catalyzed functionalization of OLNPs at pH 2.0 and pH 12.0 via oxirane ring‐opening reactions were successfully performed. We also demonstrated these new functionalized particles as efficient pH‐switchable dye adsorbents and anticorrosive particulate coatings.

High-Molecular-Weight Fractions of Spruce and Eucalyptus Lignin as a Perspective Nanoparticle-Based Platform for a Therapy Delivery in Liver Cancer

“…Due to a high number of accessible functional groups on the surface of LNPs, as shown also in this study, LNPs can be easily modified to carry small and large molecules (proteins, chemotherapy, genotherapy, etc.). For instance, the hydration barrier and the ability for acid and base-catalyzed surface modifications of lignin oleate NPs have been recently described in a study by Moreno et al (2021).…”

A Rapid and Reversible pH Control Process for the Formation and Dissociation of Lignin Nanoparticles

“…The LNPs could be rapidly regenerated to the original spherical shape upon switching pH, suggesting the excellent reversibility and controllability of the LNPs fabrication (Figure 3). Although some previous studies determined that the high stability of LNPs at different pH environments can be beneficial for their retention and large‐scale production, [6b,15b,18] the rapid and reversible fabrication of LNPs opens a new route for lignin valorization.…”

Multifunctional lignin-based nanocomposites and nanohybrids

“…showed that particles analogous to LNPs, but prepared using lignin oleate, contain a hydration barrier layer resulting from the hydrophobic acyl chains that hinder protonation and deprotonation of carboxylic acid and phenolic hydroxyl groups under acidic and alkaline conditions. 374 The OLNPs (oleiclignin nanoparticles) were surface-modified without any crosslinking directly in aqueous dispersions using epoxy ringopening reactions at pH 2 and pH 12. The resulting methacrylated and cationized particles showed competitive performance as curable anticorrosion coatings and pH-controlled switchable cationic/anionic adsorbents for rapid water purification.…”