Dynamics of methylene chains in an intercalated surfactant bilayer by solid-state NMR spectroscopy

The interlayer swelling and molecular packing in organoclays

“…Such structures contrast with previously proposed structures of organoclays in which it was assumed that interlayer surfactants either lie flat and parallel to clay surface or are tilted at rather precise angles. The recent literature contains numerous studies using a variety of techniques that point to a rather different picture that in many ways is quite consistent with the results and interpretations presented here [9,[27][28][29][30][31].…”

“…The coexistence of trans and gauche conformations can be attributed to the relatively small energy difference between these two conformations. The average fraction of trans conformations about 0.60 is comparable to the qualitative prediction from NMR [27] and vibrational spectra [28] on intercalated alkyl chains in layered solids.…”

“…Recent FTIR and NMR studies have shown that both trans and gauche conformations exist in organoclays, which suggests more random packing arrangements [12,13]. The recent efforts to form polymer nanocomposites from organoclays have renewed interest in the fundamental issue of surfactant molecular packing in these materials [8,[14][15][16][17][18][19][20][21][22][23].…”

Structure and Dynamics of Cationic Surfactants Intercalated in Synthetic Clays

“…22 Such a paraffin complex has been also postulated for HDTA cations intercalated between sheets of cadmium thiophosphate CdPS 3 . 23 Intercalation of HEDMHA or DHEMHA in Laponite and saponites leads to trans/gauche conformational ratios similar to that obtained with HDTA ( Table 1).…”

Thermal and colloidal behavior of amine-treated clays: The role of amphiphilic organic cation concentration

“…However, recent studies [20][21][22][23] claim that the conformation of the surfactant tails is more random, which means that the step changes shown in Fig. 3 may not be as clear-cut as drawn in the figure.…”