Headgroup and hydrocarbon tail effects on the surface tension of sugar-based surfactant solutions.
Headgroup and hydrocarbon tail effects on the surface tension of sugar-based surfactant solutions.
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DOI：
10.1021/la048815z
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发表时间：
2004-12
期刊：
影响因子：
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通讯作者：
Atte J Kumpulainen;C. Persson;J. Eriksson
中科院分区：
文献类型：
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作者：
Atte J Kumpulainen;C. Persson;J. Eriksson
测定了N-十烷基-β-d-葡萄糖苷(C(10)-Glu)和N-十烷基-β-d-麦芽糖苷(C(10)-MAL)表面活性剂水溶液的表面张力等温线。应用Gibbs表面张力方程，求出了不同组成和浓度下谷氨酸和甲基铝的表面密度。将表面分数与理论计算值进行了比较，其中磁头组被建模为硬盘。在1：1混合的情况下，22.9和11.3A(2)的硬盘大小得到了令人满意的一致。硬盘计算的结果被用来估算正癸基碳氢链的构型自由能。所得结果与前人对正十二烷基链的计算结果吻合较好。与正十二烷基β-d-麦芽吡喃糖苷(C(12)-MAL)的比较表明有进一步的贡献，较长的碳氢链导致较高的表面张力，这与碳氢液体的数据一致。此外，通过比较正十二烷基环氧乙烷表面活性剂和正十二烷基β-D-硫代吡喃葡萄糖苷(C(10)-S-MAL和C(12)-S-MAL)和-麦芽吡喃糖苷的表面张力数据，研究了头基对碳氢化合物膜的渗透作用。结果发现，将四(环氧乙烷)链延长一段对表面张力的影响很小，表明额外的环氧乙烷基团几乎没有穿透到碳氢膜中。然而，对于硫代麦芽糖苷，相应的效果被发现非常高。
Measurements of surface tension isotherms were conducted for water solutions of pure and mixed n-decyl-beta-d-glucopyranoside (C(10)-Glu) and n-decyl-beta-d-maltopyranoside (C(10)-Mal) surfactants. By applying the Gibbs surface tension equation, the surface densities of Glu and Mal were derived for different compositions and concentrations. The surface fractions were compared with theoretically calculated values where the headgroups were modeled as hard disks. Satisfactory agreement was found for hard-disk sizes of 22.9 and 11.3 A(2) in the case of a 1:1 mixture. The results of the hard-disk calculations were employed to estimate the configurational free energy of the n-decyl-hydrocarbon chain. The results obtained agree well with previous calculations for the n-dodecyl chain. Comparison with n-dodecyl beta-d-maltopyranoside (C(12)-Mal) indicated a further contribution, with the longer hydrocarbon chain giving rise to a higher surface tension in good agreement with data for hydrocarbon liquids. Furthermore, the interpenetration of the headgroup into the hydrocarbon film was studied by means of comparing surface-tension data for n-decyl- and n-dodecyl-ethylene-oxide-based surfactants and n-decyl- and n-dodecyl-beta-d-thiomaltopyranosides (C(10)-S-Mal and C(12)-S-Mal, respectively) and -maltopyranosides. It was found that lengthening the tetra(etylene oxide) chain by one segment affects the surface tension only marginally, indicating little interpenetration of the additional ethylene-oxide group into the hydrocarbon film. For the thiomaltosides, however, the corresponding effect was found to be remarkably high.