Turning the morphology and wetting ability of self-assembled hierarchical structures from lignin stearoyl esters

Abstract

Well-organized and self-assembled structures with hierarchical surface architectures have recently attracted considerable attention due to their potentially wide application range. Herein, remarkable lignin-based petaloid nanoflakes (LPNFs) were formed via the crystallization of polymeric lignin stearoyl esters (LSEs). A solvent exchange self-assembly technique using Tetrahydrofuran (THF) as a solvent in addition to ethanol, acetone, and water as nonsolvents was used to form LPNFs by the crystallization of the stearyl groups in LSEs during evaporation. The grafting level of the stearoyl groups in the LSEs, the difference of the nonsolvent, and the volume ratios of the solvent/nonsolvent during the solvent exchange process predominantly determined the formation of LPNFs via this process. The self-assembled structures could be constructed as spherical particles and as constituted LPNFs structures with well-organized petaloid nanoflakes. By introducing sufficient amounts of LPNFs patterns on the substrates (e.g., glass slide, paper, and wood), the hydrophilic substrates were successfully transformed into superhydrophobic surfaces. Thus, the synthesis of LSEs and the formation of LPNFs with tunable structures offer a new strategy for the derivation and value-added utilization of lignin.