Adsorption behavior of weak hydrophilic substances on low-energy surface in aqueous medium

Through the methods such as measurements of contact angle and surface tension, calculations of surface energy and interfacial interaction free energy, and four weak hydrophilic substances (WHS) were taken as research objects, some interesting conclusions were obtained as follow. In aqueous medium, the WHS give priority to adsorb on low-energy surface that is low polar or particularly non-polar. There is a clear corresponding relationship between the free energy and Lewis base component γ− or the hydrophile index of low-energy surface, and the specific relationship is obtained. Finally, we find hydrophobic attractive force of the Lewis acid-base interaction is mainly responsible for the absorption of WHS on low-energy surface. In short, an initial insight into adsorption behavior of WHS on low-energy surface is demonstrated in this paper.

There is a clear corresponding relationship between the free energy and hydrophile index of material surface, and the specific relationship is close to a simple linear relationship.Highlights► The adsorption of weak hydrophilic substance on low-energy surface can not be neglected. not like dealing with the high-energy surface system. ► A simple linear relationship exist between the interfacial interactive free energy and the hydrophilic index. ► The Lewis acid-base interaction is the main responsible for the absorption of weak hydrophilic substance on low-energy surface in aqueous medium.