Critical adsorption in the weak surface field limit

We study critical adsorption in the small surface field (hl) limit using a homologous series of critical liquid mixtures. The experiment data, in the one-phase regime, is accurately described by a universal surface scaling fu nction G(+)(z/xi (+), z/l(h)) at distance z from the interface with correla tion length xi (+) and surface field length l(h) similar to \h(l)\(-v/Delta l), where h(l) similar to Delta (sigma), the surface energy difference betw een the two components.