[Terminology] Ultra-low interface tension
Definition: interface tension which is less than 10-3mN/m (0.001mN/m).
Generally, interfacial tension between 10-2 - 10-1mN/m (0.01 - 0.1mN/m) is called low interface tension.
In general, ultra-low interfacial tension can be measured by Spinning Drop Method.
A typical application field of ultra-low interface tension is oil recovery, which is of great significance for improving oil recovery.