Non-covalent interactions drive the Young modulus of oligolignols-cellulose complexes.

Oligolignols composition in an efficient adhesive formulation, were studied to identify the interactions that drive their contact and Young’s modulus with a cellulose surface. Oligolignols’ molecular structures were modeled to elucidate the formation of complexes over a crystallite model of cellulose Iβ. Hybrid quantum mechanics/molecular mechanics (QM/MM) computations were carried out for the coupled molecular geometries of the oligolignol-cellulose complexes. The achieved conformations were used to obtain wavefunctions at the interaction region to develop a non-covalent interactions (NCI) study from the atoms in molecules (AIM) theory, implemented through graphics processing units (GPUs) calculations. It was found that non-covalent interactions command the forces associated to adhesive-cellulose contacts, mainly by C-H···O hydrogen bonds, driving the long-range interactions that promote the adhesion of oligolignols on cellulose Iβ. Furthermore, the results of interaction energy suggest that the strongest Young’s modulus is obtained from oligolignols with two and three monolignols on our cellulose Iβ crystallite model. We propose a QM/MM study considering NCI and AIM analysis, as a significant new framework to design adhesive formulations. Besides, the present work can contribute to the description of interactions between lignin components and cellulose.