Pectin Mucilage Adhesion on a Flat Substrate: A Molecular Simulation Approach to Plant-Seed Adhesion

We investigate the adhesion of pectin-mucilage-coated seeds to substrate surfaces, focusing on the effect of water content. It is known that the adhesion of pectin mucilage increases with water loss, eventually dropping to zero beyond a certain point. To explore this phenomenon, we develop and parametrize a coarse-grained many-body dissipative-particle dynamics (MDPD) model. First, we examine the adhesion of water between two flat surfaces to understand the factors influencing the pull-off force. Then, we determine the pull-off force of polymer solutions with varying pectin concentrations. Our findings show that the pull-off force increases as the pectin content rises and as water is lost. This is because more pectin becomes available to interact with the substrate surface, enhancing adhesive strength. Additionally, the concentration-driven transition of the polymer from a melt state to a glassy state must be considered, as it significantly affects the pull-off force.