Confined evaporation-induced self-assembly of colloidal lignin particles for anisotropic adhesion

Colloidal lignin particles out of lignocellulosic biorefineries have gained interest due to their improved properties and wide application range compared to standard lignin. In this work, an application as green adhesive was investigated. Solely a suspension of aqueous colloidal lignin particles was used to achieve anisotropic adhesion between two glass slides. The self-assembly of the colloidal lignin particles into macroscopic structures during drying lead to shear strength 8-times higher the tensile strength. Predefined lignin particles are crucial for the adhesion whereas dissolved lignin leads to no practicable adhesion. The high anisotropy of the adhesion and the fact that solely pure lignin is necessary opens new application and research fields and will propagate the application of colloidal lignin particles even more.