Benchtop MRI Study on the Contact Angle of the Solid-Liquid Interface

Benchtop MRI Study on the Contact Angle of the Solid-Liquid Interface

Benchtop MRI can be used to obtain images of water-glass-oil interface and water-glass-benzene interface that are difficult to obtain by ordinary optical methods, and the contact angle of the interface can be studied by Benchtop MRI technology.

The measurement of the contact angle of transparent liquids generally uses optical methods to obtain data. However, optical methods cannot measure the three-phase contact angles formed by two immiscible transparent liquids and solids. MRI can compensate for the defects of optical methods through NMR. Imaging can study the contact angle of the interface.

Solid-liquid contact angle

The concept of contact angle originates from the gas-liquid-solid three-phase interface, and the angle between the gas-liquid and solid-liquid interface is called the contact angle. When the gas in the definition is changed to another incompatible liquid, a liquid-solid-liquid contact angle is formed.

Schematic diagram of general contact angle definition

The following figure shows the contact angle formed by solid particles on the oil-water interface. Its size determines the type and stability of the emulsion that may be formed, which plays an important role in oil and gas production and transportation.

Three different contact angles formed by solid particles on the water-oil interface

Measuring the contact angle of solid-liquid interface with Benchtop MRI technology

The spin echo pulse sequence and inversion recovery pulse sequence of NMR technology can realize proton density imaging, T1-weighted imaging, T2-weighted imaging, etc. of small-volume liquid samples. Different types of NMR signals can be distinguished by imaging, so that two hydrogen-containing liquids can be separated on the image gray level and a clear image of the contact angle can be obtained.