Stearate Intercalated Layered Double Hydroxides

Stearate anions (SA) were successfully intercalated§into a layered double hydroxide (LDH-CO3) to form§LDH-SA. The intercalation method involved the§acid-base reaction between emulsified stearic acid§and carbonate anions in aqueous media. This method§led to the formation of more LDH-SA than well known§methods such as melting the carboxylic acid in the§presence of the LDH, allowing the interlayer region§to swell in the presence of glycerol and§reconstructing the calcined LDH in the presence of§aqueous sodium stearate. Other literature methods§involve ion-exchange of chloride in LDH-Cl with§stearate in aqueous sodium stearate, usually under§nitrogen atmosphere. The LDH-SA was successfully used§to intercalate sodium polyvinyl sulphonate by an ion§exchange with the intercalated stearate, without the§need for a nitrogen atmosphere. The same§intercalation reaction was allowed to take place in§situ during the formation of§dextrin-alginate-glycerol film solutions in§water-ethanol media. The stearate intercalated as a§bilayer in the interlayer region of the LDH. This§reduced the water vapour permeability of the films.