Gemini surfactant modified clays Effect of surfactant loading and spacer length

Aromatic-containing gemini ammonium bromide surfactants with different spacer length and variable amounts were used to modify Na+-montmorillonite via ion exchange reaction. The resulting organoclays (OMt) were characterized in terms of composition and morphology using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The thermal stability of OMt was determined by thermogravimetric analysis (TGA). The results indicated that gemini surfactants exhibit a good efficiency to modify clay mineral. Surfactant concentration and the length of the spacer connecting the ammonium heads were found to be key parameters governing the thermal stability and the structure of the corresponding OMt. Increasing surfactant concentration and lengthening of the spacer act favorably for the achievement of higher expended interlayer clay structures with better thermal stability. Different configurations of surfactant molecules within Mt interlayers were proposed based on d(001) basal spacing