Molecular Dynamics Simulation of the Interfacial Effect of Cellulose Ether in Sandy Soil Improvement

Due to their loose physical structure and low cohesion, sandy soil slopes are highly susceptible to rainfall erosion under natural conditions, leading to soil erosion and slope instability. The traditional slope protection methods are characterized by high cost, high environmental impact, and complicated construction, which make it difficult to meet the needs of ecological restoration and economic efficiency. Cellulose ether, as a natural cellulose modification product, has high adhesive strength, good water retention, and ecological and environmental protection and has a broad prospect in soil improvement and slope protection. However, its microscopic adsorption mechanism on the surface of soil particles, especially the adsorption behavior under different water content and temperature conditions, has not been fully understood. In this paper, a ternary composite model of "cellulose ether-water-silica" was constructed by molecular dynamics (MD) simulation, and the interfacial interactions between cellulose ether and the sandy soil surface were analyzed by calculating the adsorption energy, the number of hydrogen bonds, and the radial distribution function (RDF). The results showed that (1) the increase of water content significantly weakened the adsorption energy and the number of hydrogen bonds between cellulose ether and the sandy soil surface, and the sensitivity of different types of cellulose ether to the change of water content was different; (2) the number and structure of functional groups play a key role in the adsorption performance of cellulose ether, and the higher the hydroxyl content, the stronger the adsorption capacity; and (3) the temperature has a significant effect on the adsorption behavior of cellulose ether, and different cellulose ethers exhibited distinct temperature response characteristics. This study provides a theoretical basis and technical reference for the molecular design of ecological protective materials for sandy slopes.