Evaluation of Surface Free Energy Inducing Interfacial Adhesion of Amphiphilic Cellulose Nanofibrils

Cellulose nanofibrils (CNFs) have been studied extensivelyoverthe past decade. Their applications, e.g., as fillers for nanocomposites,stabilizers for Pickering emulsions, and scaffolds for cell culture,are mostly dictated by interfacial adhesion. In general, the individualsurface free energy values of the constituents of a material correlatewith its adsorption and desorption behaviors. In the present study,we estimated the surface free energy values of thin films composedof CNFs using traditional contact angle methods based on the Wenzelequation and van Oss-Chaudhury-Good theory. The accuracyand utility of the estimated surface free energy values were verifiedby close matching between the obtained adhesion energy values andthe actual interfacial adsorption behaviors of the CNFs. Therefore,the evaluated surface energy values are expected to be a feasibletool for designing of interfacial interactions between CNF surfacesand other materials.