Soap film categories

These are the three main categories of soap film behaviour. Soap films need not fall into one of these three but can have a behaviour of an intermediate character. For example a soap film could have a behaviour typical of a simple mobile film with a small amount of critical fall. 

A third class of industrial chemical biocides consists of agents with the ability to inhibit biological film formation, also called surfactants . The term surfactant originates from the phrase surface active agent. Surfactants fall into four broad categories anionic (e.g., soaps, alkyl benzenesulfonates, alkyl sulfonates, alkyl phosphates), cationic (e.g., quaternary ammonium salts), nonionic (e.g., alkyl polyglycosides, alcohol ethoxylates, alkylphenol ethoxylates), and zwitterionic. 

Indeed, when one operated under snitable conditions, the first was shown, immediately or shortly after the development of the film, in caps of all the liquids of the second category, except, of course, those of carbon bisulphide it was undoubtedly shown also in those of rosin soap, though one conld not clearly dednce it from the colors of the rings finally it was again shown, after the long white phase, in the household soap caps. The phenomenon probably occurs, in the other caps of the third category, during the white phase, and in all those of the first but the absence of colors does not make it possible to be certain of it. 

One sees, according to this discussion, that, in the films of the third category, the moment of rupture is hastened by evaporation also our caps of household soap solution ( 248) which, in an atmosphere saturated with water vapor, persisted several hours, lasted only four to five minutes when they were produced in the closed bottle, but without saturation of its atmosphere if one had formed them in the entirely open air, no doubt they would have burst earlier still. 

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