A method of preparing an aqueous lignin nanoparticle dispersion, comprising the steps of: combining (a) a base, wherein the base is not an inorganic divalent base, (b) lignin, and (c) water to form a lignin composition comprising from 1 to 70 wt% lignin, in particular from 5 to 40wt% lignin, and more particularly from 15 to 30 wt% lignin, wherein, when the lignin is combined with water, the mixture of lignin and water would have a pH less than or equal to 6; and - heating the lignin composition while mixing to form a stable dispersion of lignin nanoparticles, wherein the lignin is selected from the group consisting of isolated lignin, derivatized lignin and combinations thereof, wherein derivatized lignin is selected from: (i) lignin derivatized by heat treating at temperatures ranging from 120 to 200 °C, optionally followed by reduction or oxidation; (ii) lignin derivatized by alkylation of the hydroxyl group(s) of the lignin by reacting lignin with alcohol in the presence of a catalyst, or reacting the lignin with at least one of alkyl halides, alkyl sulfates and alkylene epoxides; (iii) lignin derivatized by methylolation or amination by attaching lignin to at least one of the functionalities (a) CH 2 OR through reactions with formaldehyde in water or with an alcohol, or (b) CH 2 N(R')R" if combined with an amine, where R, R' and R" are hydrogen or alkyl groups; (iv) lignin derivatized by carboxylation by at least one of oxidation, alkylation by halogenated carboxylic acid, or by Kolb-Schmitt reaction wherein CO 2 is reacted with the phenol group(s) of lignin to add a carboxylic acid to the aromatic ring; (v) lignin derivatized by sulfomethylation or sulfonation, adding at least one of the groups of methylene sulfonate and sulfonate to lignin; (vi) lignin derivatized by phosphorylation, adding at least one phosphate group to lignin; (vii) lignin derivatized by esterification of lignin, by reacting the hydroxyl group(s) of lignin with a carboxylic acid anhydride or chloride, or alternatively through transesterification; (viii) lignin derivatized under anhydrous conditions, wherein the aromatic ring(s) of lignin are alkylated or acylated through carbocation intermediates; and (ix) lignin derivatized by grafting polymerization to introduce polymer chains to lignin, or by ring opening polymerization, or alternatively by step growth polymerization. - heating the lignin composition while mixing to form a stable dispersion of lignin nanoparticles, (i) lignin derivatized by heat treating at temperatures ranging from 120 to 200 °C, optionally followed by reduction or oxidation; (ii) lignin derivatized by alkylation of the hydroxyl group(s) of the lignin by reacting lignin with alcohol in the presence of a catalyst, or reacting the lignin with at least one of alkyl halides, alkyl sulfates and alkylene epoxides; (iii) lignin derivatized by methylolation or amination by attaching lignin to at least one of the functionalities (a) CH 2 OR through reactions with formaldehyde in water or with an alcohol, or (b) CH 2 N(R')R" if combined with an amine, where R, R' and R" are hydrogen or alkyl groups; (iv) lignin derivatized by carboxylation by at least one of oxidation, alkylation by halogenated carboxylic acid, or by Kolb-Schmitt reaction wherein CO 2 is reacted with the phenol group(s) of lignin to add a carboxylic acid to the aromatic ring; (v) lignin derivatized by sulfomethylation or sulfonation, adding at least one of the groups of methylene sulfonate and sulfonate to lignin; (vi) lignin derivatized by phosphorylation, adding at least one phosphate group to lignin; (vii) lignin derivatized by esterification of lignin, by reacting the hydroxyl group(s) of lignin with a carboxylic acid anhydride or chloride, or alternatively through transesterification; (viii) lignin derivatized under anhydrous conditions, wherein the aromatic ring(s) of lignin are alkylated or acylated through carbocation intermediates; and (ix) lignin derivatized by grafting polymerization to introduce polymer chains to lignin, or by ring opening polymerization, or alternatively by step growth polymerization.