On the nature of the superspreaders

Abstract

This is a review article on the basic and the latest achievements on superspreading. The complete and fast spreading of droplets on many surfaces in the nature is a special phenomenon discovered in 1960-ies Intensive studies on this phenomenon have been conducted since that time, but the mechanism of superspreading remained in completely unveiled till nowadays. Here we scrutinized the basic literature on superspreading from the last 25 years and also present results related to superspreaders acquired in the present work. The literature in superspreading can be divided to the following groups: (i) works on the properties of the trisiloxane surfactants; (ii) works on the mechanisms of superspreading; (iii) MD simulations; (iv) works on the effect of the trisiloxane surfactants on thin liquid films. There is a number of review articles published in the last decade related to mainly works from groups (i) and (ii). The works on MD simulations (iii) and the effects on trisiloxane surfactants on thin liquid films (iv) are still few despite they are important from the scientific view point. We conducted our own study on the effect of the superspreaders on foam films in rectangular frame and confirmed that the superspreaders cause powerful Marangoni effect within the foam films. Such a strong Marangoni effect has been never observed with the ordinary surfactants. We scrutinized and discussed the basic works from the groups (i)-(iv) on the superspreading and added our own investigation on the distinguishable effects of superspreaders and non-superspreaders on thin foam films. The work could be useful to both beginners and specialists in the field of wetting/de-wetting and superspreading.

Keywords: Siloxane surfactants; Superspreaders; Surfactants; Thin liquid films; Wetting.