Many simple molecules are dipolar… they have a slight positive end and a slight negative end. When you condense these molecules into films then you would expect that to reduce the total energy of the system that the molecules would be arranged with their dipoles in opposition… positive to negative and negative to positive… a bit like bar magnets. This doesn’t happen with some molecules… they orient themselves with all the positive sides together and all the negative sides together. This is energetically unstable. We don’t know why this happens but we’ve been involved in finding out that it does. We hope that in the next few years we can work out why and predict this behaviour.