We propose to make neutron reflectivity measurements of the weak polyelectrolyte, poly(dimethy amino ethyl methacrylate), grown from two different surface densities of initiator group attached at the sapphire-water interface by adsorbed macro-initiator molecules. We will change the charge of the polyelectrolyte by measuring at pH3 and pH9 and will consider how these layers interact with sodium dodecyl sulphate. In particular, we are looking to see if the multilayer structures formed at the air-water interface will assemble at the solid-water interface. By measuring in two contrasts, we will be able to determine the distribution of both the polymer segments and the surfactant. We have slowed the polymerization down sufficiently, to make an in-situ kinetic measurement of the growth by neutron reflectivity feasible, and we plan to make the first such measurement.