This proposal is part of a major EPSRC (EP/GR065705)/Unilever funded programme to develop and control the spontaneous formation of surfactant multilayer structures at interfaces; a potentially important structural motif for a wide range of technological applications. This proposal focuses on surface multilayer formation induced by low MW polyelectrolytes, oligoamines, with SDS. Preliminary NR measurements show that the conditions for multilayer formation shift from being predominantly at pH 3 to 7 as the MW increases from tetramine to hexamine. This can be interpreted as a change in the oligoamine function from multivalent ion to polyelectrolyte, and we request beam time on INTER to investigate this important transition.