Evolution of droplet size in nonaqueous emulsions using time-resolved, time-of-flight SESANS

Emulsions consist of two immiscible fluids (most often water and oil), where one can be dispersed in the other. In addition to mixing water and oil, there is considerable interest in understanding emulsification of immiscible nonaqueous fluids (oil-in-oil emulsions), which have many applications. Techniques that can measure the droplet size over relevant length scales are required. Spin-echo SANS (SESANS) is a scattering technique suited for this purpose, due to its sensitivity to large (µm) length scales and its tolerance of large amounts of scattering. In this experiment, time-resolved measurements will be performed that will reveal the evolution of the particle size of nonaqueous emulsion droplets, using time-of-flight SESANS, a technique available on the Larmor instrument at ISIS that can measure scattering over a wide range of length scales simultaneously.

乳状液由两种不互溶流体（最常见为水与油）组成，其中一相可分散于另一相之中。除常规的水油体系外，学界对非水不互溶流体的乳化过程——即油包油乳状液——也有着浓厚的研究兴趣，这类体系拥有诸多实际应用。此类研究亟需可在对应长度尺度下精准测量液滴尺寸的技术。自旋回波小角中子散射（Spin-echo SANS，SESANS）正是适配该需求的散射技术，其不仅对微米级长度尺度具备优异敏感性，还可耐受高强度散射信号。本实验将采用飞行时间型自旋回波小角中子散射技术开展时间分辨测量，以揭示非水乳状液液滴的粒径演化历程；该技术可在ISIS散裂中子源的拉莫尔仪器（Larmor instrument）上运行，能够同时覆盖宽范围的长度尺度完成散射测量。