Density profiles have been studied of a hard sphere chain fluid and of dimerizing hard spheres near a crystalline wall represented as a lattice of sticky sites. The associative Henderson–Abraham–Barker equation in the PY approximation is used for the calculation of a structure with the adsorption isotherm assumed to be of the mean-field form. It is shown that the density profiles exhibit a sudden change corresponding to critical behaviour of the adsorption isotherm. The influence of the low-density critical point, caused by the intramolecular correlation in a chain, on the interfacial structure is determined. It is also shown that the associative interparticle interaction forms a sharp edge of the second adlayer. The density of this adlayer is analytically calculated.