PREDICTING KEY POLYMER PROPERTIES TO REDUCE EROSION IN IRRIGATED SOIL

The ability to understand and/or predict the physical properties of po lymers is important in efforts to help reduce erosion in irrigated lan d by treating irrigation water with minute amounts of certain polymers . The key properties of polymers for this application (water solubilit y and water absorption capability, dilute solution properties, and sta bility) are discussed. Methods used to predict the properties of polym ers include quantitative structure-property relationships, statistical mechanical theories, atomistic simulations, and quantum mechanical ca lculations. Each general method is best applied to different types of problems. For example, combination of quantum mechanical calculations and atomistic simulations may shed light on the solution conformation of a polymer and hence on its soil activity. On the other hand, a new method, based mainly on topological descriptors called connectivity in dices, predicts key polymer physical properties very rapidly from the structures of polymeric repeat units via empirical and semi-empirical quantitative structure-property relationships. This new method can be used for the overall evaluation of the potential of candidate polymers for erosion reduction. Applications of this method to polyacrylamide and structural variants and copolymers are discussed. An outlook is pr ovided for the future of applications of computational chemistry to wa ter-soluble polymers. It is suggested that significant future advances can be expected from further developments of each of the different ty pes of theoretical methods, as well as from their more synergistic and interdisciplinary utilization.