Table 2.
Some complementary examples regarding clay minerals for use in Pickering emulsions.
| Classes/Species | Chemical Composition | Applications | Size Variations | Locations or Occurrences | Model Applications | Ref. |
|---|---|---|---|---|---|---|
| Montmorillonite Smectites (Bentonites and vermiculites) |
(Na,Ca)0.33(Al,Mg)2Si4O10 (OH)2·(H2O)n |
In cosmetology (formulations of make-up, shampoos, and skin emulsions) and in drug delivery, and in the synthesis of polymer–clay nanocomposites in tissue engineering. | Average diameter of around 7 µm. They are alkaline compounds in nature |
Paraíba (Municipalities of Cubati and Boa Vista) northeast Brazil |
Montmorillonite-stabilized Pickering emulsions were formed at high salinities. | [130,131,132,133,134] |
| Illites (Glauconites) | (Si4)(Al,Mg, Fe)2,3 O10(OH)2.(K,H2O) | Has been widely used as an adsorbent in water treatment applications in removing different metal ions and dyes. | Ranges from 125 to 500 µm | Usually occur in microscopic crystals on land masses | - | [135,136,137] |
| Kaolinite (Kaolin) |
Al4Si4O10(OH)8 | Application as an oil/water emulsion stabilizer and oil recovery and has been used for centuries in pharmaceutical preparations of intestinal adsorbent drugs and other therapeutically useful applications. | Particle sizes of 2–5 µm | In the state of Rio de Janeiro, there are currently occurrences of kaolin in the municipalities of Magé, Valença, Sapucaia, Petrópolis, Itatiaia, Araruama, and Rio de Janeiro. Capim River in Pará |
Study aimed to investigate the preparation and characterization of oil-in-water (O/W) Pickering emulsions stabilized with three different phyllosilicates: kaolin, halloysite, and palygorskite. Stable O/W emulsions could be obtained without additional surfactant or surface treatment. | [137,138,139,140,141,142,143] |
| Chlorite | (Mg,Fe)3(Si,Al)4O10(OH)2·(Mg, Fe)3(OH)6 | Widely used in the pharmaceutical industry as lubricants, desiccants, disintegrants, diluents, binders, pigments, and opacifiers. | Approximately 0.5 to 10 µm and thickness ranging from 0.1 to 1.0 µm | They are common in clayey rocks, recent marine sediments, most soils, and in mines. Found in Furnas and Lageado, in the state of São Paulo, Panelas, and Canoas, in the state of Paraná and Rio Grande do Sul |
- | [137,144,145,146] |
| Laponite | Na0,7[(Si8MgLi0,3)O20(OH)4]0,7 | Medicine, pharmacy, and food packaging; in addition, presents great potential as an adsorbent of organic pollutant compounds such as pesticides. Used in the polymerization of Pickering emulsions. | 1 and 30 nm diameter | Synthetic material with a similar structure and composition to natural hectorite. |
Pickering emulsion polymerization using laponite clay as a stabilizer to prepare armored “soft” polymer latexes | [147,148,149,150,151,152,153] |