Surface force confinement cell for neutron reflectometry studies of complex fluids under nano-confinement

Abstract

In this paper, we describe the construction of a new neutron surface force confinement cell (NSFCC). The NSFCC is equipped with hydraulically powered in-situ, temporally stable, force control system for simultaneous neutron reflectometry studies of nano-confined complex fluid systems. Test measurements with deuterated toluene confined between two opposing diblock copolymer (polystyrene + poly 2-vinylpyridine) coated quartz substrates demonstrate the capabilities of the NSFCC. With increasing hydraulically-applied force, a series of well-defined decreasing separations were observed from neutron reflectivity measurements. No noticeable changes in the hydraulic pressure used for controlling the surface separation were observed during the measurements, demonstrating the high stability of the apparatus. This newly designed NSFCC introduces a higher level of control for studies of confinement and consequent finite size effects on nano-scale structure in a variety of complex fluid and soft condensed matter systems.