Blue light-triggered click reactions of betulin and lignin nanoparticles and their emulsions

Abstract

Activating and controlling chemical reactions by the use of light is becoming increasingly important for the synthesis of nanomaterials. A key challenge is the lack of reactive bio-based particles that can replace fossil-based nano- and microparticles, which are currently essential for creating supraparticle materials. Here we show nanoparticle dispersions of propargylated lignin and betulin azide as bio-based substances that absorb light in a broad wavelength range and show their thermal, catalytic, and photochemical click reactions. We use energy-efficient light-emitting diode (LED) technology to initiate click reactions in water at room temperature. This method enables controlled inter-particle reactions, demonstrated by confined click reactions at oil-in-water interfaces of Pickering emulsions to crosslink particles. These results illuminate the emerging field of click reactions of wood-derived building blocks, revealing controlled nanoparticle aggregation for advanced material development.