Colloidal lignin nanoparticles are promising building
blocks for
sustainable functional materials. However, their instability in organic
solvents and aqueous alkali limits their applicability. Current stabilization
methods require nonrenewable and toxic reagents or tedious workup
procedures. Here we show a method to prepare hybrid nanoparticles
using only natural components. Urushi, a form of black oriental lacquer,
and lignin are coaggregated to form hybrid particles, with Urushi
acting as a sustainable component that stabilizes the particles via
hydration barrier effect and thermally triggered internal cross-linking.
The weight fractions of the two components can be adjusted to achieve
the desired level of stabilization. Hybrid particles with Urushi content
>25 wt % undergo interparticle cross-linking that produces multifunctional
hydrophobic protective coatings that improve the water resistance
of wood. This approach provides a sustainable and efficient method
for stabilizing lignin nanoparticles and opens up neoteric possibilities
for the development of lignin-based advanced functional materials.