Institute for Thermal Process Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany.
Institute for Mechanical Engineering and Mechanics, Karlsruhe Institute of Technology, Karlsruhe, Germany.
Magn Reson Chem. 2022 Dec;60(12):1131-1147. doi: 10.1002/mrc.5305. Epub 2022 Sep 2.
The crystallization of melt emulsions is of great interest to the food, cosmetic, and pharmaceutical industries. Surfactants are used in emulsions and suspensions to stabilize the dispersed phase; thus, questions arise about the liquid-liquid and solid-liquid interfaces of the droplets or particles and the distribution of the surfactant in the different phases (continuous and dispersed phase, interface). Nuclear magnetic resonance relaxation and diffusion measurements revealed that the internal and rotational mobility of surfactant molecules at the liquid-liquid interface decreases with increasing droplet sizes. Additionally, solid-liquid interfaces have fewer surfactants than liquid-liquid interfaces as a result of the desorption of the surfactant molecules during the crystallization of the droplets. Relaxation rates of surfactant molecules in aqueous solution as single molecules, micelles, and at the liquid-liquid and solid-liquid interface are analyzed for the first time.
熔体乳状液的结晶对于食品、化妆品和制药行业具有重要意义。在乳状液和悬浮液中使用表面活性剂来稳定分散相；因此，人们对液-液和固-液界面的液滴或颗粒以及表面活性剂在不同相（连续相和分散相、界面）中的分布产生了疑问。核磁共振弛豫和扩散测量表明，随着液滴尺寸的增加，表面活性剂分子在液-液界面处的内部和旋转流动性降低。此外，由于液滴结晶过程中表面活性剂分子的解吸，固-液界面处的表面活性剂比液-液界面处的表面活性剂少。首次分析了水溶液中表面活性剂分子作为单分子、胶束以及在液-液和固-液界面处的弛豫速率。
