Contact Electrification -- why is something seemingly so simple so poorly understood?

We've all rubbed a balloon on our hair, and saw the balloon and our hair get electrostatically charged and attract each other. This seems like science for elementary school children. However, the most basic scientific questions underlying the charging do not have answers. We cannot predict from material properties whether the balloon charges positive and the hair negative, or vice versa. We don't know what limits the magnitude of charge on the balloon, or how long the charge will stay there. And a century-old debate as to whether electrons or ions are transferred is still going strong. In fact, careful scientific research often leads to confounding observations that make us feel like we are moving further away from a scientific understanding, rather than closer to one.
In this talk, I will present work from my lab which we hope gives insights into both the charging and the charge loss processes.