High pressure cell for small-angle neutron and light scattering studies of phase transitions in complex liquids

High pressure cells for both small-angle neutron scattering and light scattering studies have been designed and constructed to investigate phase transitions of complex liquids. The cells can be used for polymer blends, polymer solutions, liquid mixtures of small-molecules, etc. Pressure up to 200 MPa can be applied to the cells through a pressurizing liquid. The sample is separated from the pressurizing liquid by a free piston or an O-ring. In addition, time-resolved measurements of phase transition processes induced by a pressure drop can be carried out using the cells. The pressure is stable within 0.5 MPa for the duration of several hours. Temperature can be controlled between 273 and 523 K with an accuracy of ± 0.005 K during the measurement time of 30 minutes. In this paper, we show two preliminary experimental results as examples of applications of the cells: (i) a pressure effect on the miscibility and order-disorder transition temperature of a diblock copolymer and its microphase separation process by a pressure jump, and (ii) a pressure induced critical phenomenon in a three-component microemulsion system.