“…Analysis of these data allowed us to conclude that it is impossible to unambiguously state that the minimum value of the area occupied by a single adsorbed molecule increases with increasing elongation of the alkyl chains. The lack of such a relation has been described in the literature for heterogemini sulfobetaines [four kinds of sulfobutane betaines H-(CH 2 ) n N + (CH 3 ) 2 (CH 2 ) 4 SO 3 − with n = 12, 14, 16, 18] [4] and for a series of alkylbetaine zwitterionic gemini surfactants, 1,2-bis( N -methyl- N -carboxymethyl-alkylammonium)ethane (CnAb, n = 8, 10, 12, 14) [10]. In addition to the above, there have been no reported relationships between the surface excess at the saturated interface and the length of the alkyl chain for sulfobetaines N , N -dimethyl- N -{2-[ N ′-methyl- N ′-(3-sulfopropyl)alkylammonium]ethyl}-1-alkylammonium bromides [2C( n )AmSb, with n = 8, 10, 12, 14] [7].…”