Infrared Spectroscopy of Anionic, Cationic, and Zwitterionic Surfactants

Figure 4

Selected regions of the FTIR spectra for the DTAB molecule. (a, b) C–H stretching vibrational features; (c, d) methylene scissoring vibration and asymmetric bending mode of the head [N(CH₃)₃] methyl group. (e) CH₂ wagging region; (f) C–N stretching vibrational modes. (a) and (b) spectra refer to the DTAB packing densities: 9.6×10¹⁴ and 1.2×10¹⁵ molecules cm⁻², respectively. (b), (d), (e), and (f) spectra refer to the DTAB packing densities: 3.6×10¹⁵, 4.8×10¹⁵, 6.2×10¹⁶, and 7.2×10¹⁶ molecules cm⁻², respectively.

(a)

(b)

(c)

(d)

(e)

(f)