Effect of chemical and geometrical parameters influencing the wettability of smectite clay films

Abstract

International audienceThe wettability of three swelling clays (beidellite, nontronite and montmorillonite) exchanged with different interlayer ions (Li+, Na+, K+ and Ca2+) was investigated by using the static sessile drop method for contact angle measurements. The results show that water contact angles on clay films vary as a function of the nature of the ion with a specific behaviour of K+-exchanged clays. The effect of various parameters influencing contact angle measurements such as relative humidity (RH), particle size and surface roughness has also been examined. RH has only a limited effect on contact angles even if drop stabilisation was observed. As far as the effect of particle size is concerned, the results obtained on montmorillonite of four different sizes show that the smallest angles are obtained on films of particles of the smallest sizes for a given exchangeable ion. This is clearly linked to differences in roughness that were deduced by analysing Atomic Force Microscopy experiments. In contrast, the nature of the exchangeable cation influences roughness in the order Li+ < Na+ < K+ < Ca2+ but this order does not correspond to that deduced from the evolution of contact angles, which confirms the influence of the nature of the cation on wettability

The effect of surface modification of Palygorskite on the morphology, mechanical, and thermal properties of Nylon 6/Palygorskite nanocomposites prepared by melt compounding

“…These findings suggest that HDTBP-Pal can be better dispersed than APTMS-Pal or Purified-Pal. Contac angle measurments have been reported for other clays such as montmorillonite (MMT) [41][42][43], kaolinite [44] and smectite [45]. The values of the surface energy of Pal and modified Pal are on the same order for MMT (68.65 mJ m 22 ) and modified MMT (53.34 mJ m 22 ) with octadecylamine reported in the literature [41].…”

Effect of Surface Modification of Palygorskite on the Properties of Polypropylene/Polypropylene-g-Maleic Anhydride/Palygorskite Nanocomposites

“…Contact angle measurements have been reported for other mineral clays such as montmorillonite (MMT) [46][47][48], kaolinite [49], and smectite [50] for the purpose of verifying the surface modification of clays. Figure 3 shows profiles of the sessile droplets of ethylene glycol on the surfaces of Pal tablets.…”

Cation-controlled wetting properties of vermiculite membranes and its promise for fouling resistant oil–water separation

“…Even though it has been an extensively researched material for decades, the microscopic understanding of its wetting properties or its exploitation as a membrane is limited. Previous studies on the wetting properties of clays suggest that the wetting properties are linked to its surface charge, the nature of interlayer cations, interlayer water content, and the surface topography [13][14][15] . As far as the effect of exchangeable cations is concerned, a few studies on kaolinite, a non-swelling clay mineral, revealed conflicting results ranging from negligible impact to cation-dependent wettability 13,14,16 .…”