Equilibrium polymerization of liquid sulphur from small angle neutron scattering of sulphur solutions

The reversible singular anomaly which shows up in liquid sulphur at 159degC and is also present in sulphur solutions has been clearly detected for the first time by small angle neutron scattering in solutions of sulphur with deuterated naphtalene and of sulphur with deuterated biphenyl. The observed sudden rise of the small q limit of the scattering intensity is interpreted as the signature of an equilibrium polymerization transition with formation of long sulphur chains. Experimental measurements are in qualitative agreement with theoretical predictions based on the mean field approximation of a lattice model. (orig.)