261176-81-2Relevant articles and documents
The monolayer structure of the branched nonyl phenol oxyethylene glycols at the air-water interface
Green,Su,Lu,Penfold
, p. 1507 - 1515 (2000)
The behavior of the para-substituted nonyl phenol ethoxylates with branched nonyl chains at the air-water interface was studied to examine the effect of branching in the alkyl chain and the insertion of a benzyl ring in the alkyl chain on the monolayer structure of the nonionic surfactant. A series of para-(C4H9)2CHC6H4(OC2H4)nOH (BNPE), where n=4,8, and 12 were used in the surface tension measurements. The CMC was 1.1 ± 0.3 x 10-5 M for BNPE4, 4.0 ± 0.3 x 10-5 M for BNPE8, and 8.0 ± 0.3 x 10-5 M for BNPE12; the limiting area per molecule (Acmc) at the cmc was 46 ± 3, 61 ± 4, and 75 ± 5 sq A, respectively. For the same size of headgroups, the Acmc values were almost the same as those obtained from dodecyl ethoxylates. This indicated that Acmc for these nonionic surfactants are dependent on the size of headgroups and independent of the chemical structure of the hydrophobic chains. Nonyl phenol layers projected onto the surface normal direction were 18 ± 3 A (BNPE4), 19 ± 3 A (BNPE8), and 22 ± 3 A (BNPE12). These layers, in all cases, were nearly twice as thick as the fully extended chain, suggesting that the hydrophobic chain are widely distributed across the layer an extensive resulting in a strong mixing of the chain with the ethoxylate groups.
