I was reading about chemicals that control pore size of polyurethane foams and there it was mentioned that "tensides" decrease pore size. What are tensides? I assume it's the opposite of a surfactant, that is, it increases surface tension, but that is just my guess. I have no idea what it actually is.
I tried to Google it but strangely I just got bunch of "surfactant" results even through I wrote it just tensides. Some German site when translated from German to English changed the word tenside to surfactant, so I don't know if it is different class of chemicals or just a German word for surfactant. From the original article where I saw the word, it was written in a way as to suggest that they both are different from each other.