Preparation, characterization and formation mechanism of size-controlled lignin nanoparticles

Lignin is a renewable raw material with excellent adsorption, biodegradability, and non-toxicity. As a new, green nanomaterial, lignin nanoparticles (LNPs) have been explored as high-value renewable materials for applications in many fields. Herein, we provide a simple, rapid approach for the fabrication of size-controlled LNPs using a titrimetric nanoprecipitation method. The prepared LNPs were formed through a layer-by-layer self-assembly approach from inside to outside based on π-π interactions and had spherical shapes with porous surfaces and particle sizes from 272.0 to 915.4 nm. The average particle size of LNPs varied with stirring speed and decreased as the volume of deionized water increased. Compared with those of the original lignin, the chemical structural characteristics of LNPs did not change significantly. The proposed scheme for the preparation of LNPs is simple, inexpensive, and possesses the properties of both lignin and nanomaterials. The sizes of LNPs were controlled. Therefore, this is a good scheme for high-value applications of lignin.