The method used to attach the polyethylenimines to materials is also well known the bondingagent benzophenone has already been used to attach the anti-microbial agent to glass, polymer, paper, and metal.
In addition in some situations it will pay the agent to expend resources (bonding costs) to guarantee that he will not take certain actions which would harm the principal or to ensure that the principal will be compensated if he does take such actions.