Hexaethyleneglycol alkyl ethers

In Figure 1, the log of the cmc is shown as a function of the number of carbon atoms in the hydrocarbon chain, n, . It is clear that the nonionic surfactants (hexaethyleneglycol alkyl ethers) and the zwitterionic surfactants (N-alkyl betaines) exhibit linear relations with similar slopes of about -0.5... 

G(CH2) thus calculated is -705 cal/mol and -657 cal/mol for hexaethyleneglycol alkyl ethers and N-alkyl betaines, respectively, as shown in Table 1. 

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