A temperature-controlled electric field sample environment for small-angle neutron scattering experiments

Abstract

A new sample environment is introduced for the study of soft matter samples in electric fields using small-angle neutron scattering instruments. The sample environment is temperature controlled and features external electrodes, allowing standard quartz cuvettes to be used and conducting samples or samples containing ions to be investigated without the risk of electrochemical reactions occurring at the electrodes. For standard 12.5 mm quartz cuvettes, the maximum applied field is 8 kV/cm, and the applied field may be static or alternating (up to 10 kHz for 8 kV/cm and up to 60 kHz for 4 kV/cm). The electric fields within the sample are calculated and simulated under a number of different conditions, and the capabilities of the setup are demonstrated using a variety of liquid crystalline samples. Measurements were performed as a function of temperature and time spent in the electric field. Finally, the advantages, drawbacks, and potential optimization of the sample environment are discussed with reference to applications in the fields of complex soft matter, biology, and electrorheology.

Development of High-Voltage Electrodes for Neutron Scattering Sample Environment Devices

“…A DC electric field from two parallel plates was applied for examining phase transitions in soft matter systems but the field uniformity was not considered at all [20]. Very recently, a temperature-controlled electric field device was developed for small-angle neutron scattering experiments [21]. The device may work well for some materials/measurements but will be significantly limited when a much higher field strength is required due to the thin layer and edging effect.…”

Anisotropy factors in small-angle scattering for dilute rigid-rod suspensions

“…Thus, anisotropy factors are used exclusively in a qualitative fashion by characterizing changes in alignment-dependent scattering anisotropy within a single system (e.g. changing particle alignment with shear rate) (Walker & Wagner, 1996;Wade et al, 2020;Hayward et al, 2021). Great care must be taken when comparing anisotropy factors for different orientable particles.…”

“…The integrated axes method is the third approach examined in this work and is a modern take on the anisotropy factor (Liberatore et al, 2009;Wade et al, 2020;Hayward et al, 2021). This method requires direct integration of the scattering intensity along each axis of the scattering pattern, vertical and horizontal, for a specified q range.…”