Tuning the morphology of micro- and nano-spheres from bamboo shoot shell acetosolv lignin

Abstract The supramolecular assemblies of lignin into micro- and nano-particles (LMNPs) have attracted much attention recently. In preparing LMNPs, the antisolvent regime has been widely adopted. However, the effects of operation parameters and antisolvent coexisted substances on the morphology of LMNPs are still not well understood. Herein solid, single-holed, multi-holed and smooth-faced but inside porous spheres were obtained from bamboo (Dendrocalamus latiforus L.) shoot shell acetosolv lignin by controlling initial lignin concentration (CL0), the antisolvent addition rate (Raa), temperature and incorporating certain chemicals in antisolvent. The average size of LMNPs increased with CL0 and temperature but decreased with Raa. The relative morphology proportions highly depended on the antisolvent addition pattern, Raa, CL0, and the type and concentration of the chemical adulterated in the antisolvent. Normally, solid and single-holed spheres presented in an average size lower than 200 nm and 400 nm, while the size of multi-holed and smooth-faced but inside porous spheres were in the range of hundreds of nanometers to several microns. These results enable a deeper understanding of the morphology-setting mechanism of LMNPs and open a practical way to prepare LMNPs with diverse morphologies and potential applications.