Roles of paper composition and humidity on the adhesion between paper sheet and glass: a molecular dynamics study

Understanding adhesion behavior between paper materials and inorganic substrate is important to minimize surface contamination by paper fragments. In this work, we investigate adhesion mechanisms between paper sheet and glass in terms of molecular interaction. Molecular dynamics simulations are employed to calculate adhesion force between paper film and the silica glass surfaces. Pulling and sliding tests are simulated to find the effects of the paper compositions such as glucan, mannan, and glucuronoxylan (xylan) and humidity on the adhesion. Simulation results reveal that artificially constructed film of mannan unit shows higher adhesion than that of cellulose film which consists of glucan unit due to more amount of hydroxyl groups on the silica surface. Adhesion force of xylan-cellulose composite case by pulling test is 40% lower than cellulose-only case, whereas during the sliding test, adhesion force of the former is 100% higher than the latter. It turns out that this difference comes from the existence of nanocavity around the xylan molecule when the composite is adsorbed on the silica surface. In addition, introduction of humidity leads to a further increase of adhesion due to hydrogen bonds bridged by water molecules. It is found that the adhesion force is maximized around surface density of 10 H₂O/nm². It is discussed that consideration of the capillary force for paper may result in different adhesion response that reflects more realistic situation.