a tremendous attention owing the possibility for "on demand" engineering employing functional groups able to sense external stimuli such as pH, [5][6][7][8][9] light, [10][11][12] enzymes [13,14], and gases. [15,16] Among the advantages of these advanced materials, the most remarkable ones are the possibility to precisely control their disassembly processes in a spatiotemporal fashion, [12] and the ability to promote morphological transformations. [17,18] These features have made them a thriving research field in recent years, and attractive materials for important applications such as catalysis, biomedicine, or food technology have been developed. [19][20][21] However, most of these materials are derived from fossil resources and often are poorly biodegradable, [22] which together with the concerns about associated greenhouse gas emissions suggest that renewable polymers should play a crucial role in the development of the next generation of polymeric nanoparticles. In fact, macromolecules from renewable and abundant plant biomass are gaining a major role in the efforts to transition to a sustainable materials economy. [23][24][25] Among them, the aromatic plant polymer lignin is one of the most promising bio-based raw materials. [26][27][28][29][30][31] In this sense, lignin nanoparticles (LNPs) are postulated as prime platform for the development of stimuli-responsive nanoparticles. [32][33][34] In recent years the classical disdain on ligninbasically viewed as a byproduct from the pulp and paper industry and destined to be combusted -has given way to a paradigm shift towards the development of lignin-based advanced materials, supported by the inherent properties such as biodegradability, antioxidant activity, and absorbance of UV radiation which are preserved in LNPs. [35][36][37][38][39] In contrast to bulk lignin, LNPs resist aggregation in aqueous dispersions (pH 3-9) owing to their spherical shape and colloidal stability generated by the electrostatic repulsion forces mainly stemming from carboxylic acid and phenolic hydroxyl groups located on the surface of the particle. [40][41][42] This anionic surface charge has been exploited for physical modification of LNPs via adsorption of positively charged polyelectrolytes such as enzymes and polymers for a wide range of applications ranging from biocatalysts to composites among others. [43][44][45][46][47] Here, it is important to note that even one of the main limitations of LNPs, which arises from their dissolution in basic conditions (pH > 9) and aggregationThe design of stimuli-responsive lignin nanoparticles (LNPs) for advanced applications has hitherto been limited to the preparation of lignin-grafted polymers in which usually the lignin content is low (<25 wt.%) and its role is debatable. Here, the preparation of O 2 -responsive LNPs exceeding 75 wt.% in lignin content is shown. Softwood Kraft lignin (SKL) is coprecipitated with a modified SKL fluorinated oleic acid ester (SKL-OlF) to form colloidal stable hybrid LNPs (hy-LNPs). The hy-LNPs with a SKL-O...
In Figure 3e of the published version, the signals corresponding to the residual solvent (trifluoroethanol) are not visible. The reason for this discrepancy is that they overlayed white text boxes over the solvent trace signals to simplify the spectra and avoid confusing the non-expert reader.
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