Yoshimura Tomokazu, Ohori Ryo, Esumi Kunio
Research Group of Chemistry, Division of Natural Science, Nara Women's University, Nara, Japan.
J Oleo Sci. 2013;62(8):571-7. doi: 10.5650/jos.62.571.
Amphiphilic telomers with multiple sugar chains and a terminal undecyl or heptadecyl chain (i.e., C(n)Am-mGEMA, where n and m represent alkyl chain lengths of 11 or 17 with a degree of polymerization of 2.0 or 3.0 for glucosyloxyethyl methacrylate (GEMA) units, respectively) were synthesized via monomeric radical telomerization in the presence of 2-aminoethanethiol hydrochloride. Surface tension, pyrene fluorescence, and dynamic light scattering were measured to characterize the solution properties of the synthesized telomers. In addition, the effects of alkyl chain length and degree of polymerization of hydrophilic GEMA units on the measured properties were evaluated by comparison with those of conventional polyoxyethylene dodecyl ether nonionic surfactants. C(n)Am-mGEMA telomers exhibited higher critical micelle concentration (CMC) values than polyoxyethylene dodecyl ether surfactants with similar number of hydrophilic groups did. The synthesized telomers are highly efficient in reducing the surface tension of water, despite the relatively large hydrophilic structures within the sugar units (GEMA). A unique behavior was observed in that adsorption at the air-water interface and solution aggregation occurred simultaneously at a concentration below CMC (as determined by the surface tension method). This suggests that aggregate formation occurs readily in solution along with the adsorption at the interface because of strong attractive interactions between multiple sugar GEMA chains. Further, aggregates formed by C(n)Am-mGEMA telomers differ depending on the number of sugar chains, i.e., an increase in the degree of polymerization of the telomers increases the size of the aggregates. This indicates that it is easier for telomers with more sugar GEMA chains to form large aggregates due to the interactions between their hydroxyl groups.
合成了具有多个糖链和末端十一烷基或十七烷基链的两亲性端粒（即C(n)Am-mGEMA，其中n和m分别代表11或17的烷基链长度，甲基丙烯酸葡糖氧基乙酯（GEMA）单元的聚合度分别为2.0或3.0），方法是在2-氨基乙硫醇盐酸盐存在下进行单体自由基端粒化反应。测量了表面张力、芘荧光和动态光散射，以表征合成端粒的溶液性质。此外，通过与传统聚氧乙烯十二烷基醚非离子表面活性剂的性质进行比较，评估了亲水性GEMA单元的烷基链长度和聚合度对测量性质的影响。C(n)Am-mGEMA端粒的临界胶束浓度（CMC）值高于具有相似亲水基团数量的聚氧乙烯十二烷基醚表面活性剂。尽管糖单元（GEMA）内的亲水结构相对较大，但合成的端粒在降低水的表面张力方面非常有效。观察到一种独特的行为，即在低于CMC的浓度下（通过表面张力法测定），在气-水界面的吸附和溶液聚集同时发生。这表明由于多个糖GEMA链之间的强吸引相互作用，溶液中很容易形成聚集体并伴随着在界面的吸附。此外，由C(n)Am-mGEMA端粒形成的聚集体因糖链数量而异，即端粒聚合度的增加会增加聚集体的尺寸。这表明具有更多糖GEMA链的端粒由于其羟基之间的相互作用更容易形成大的聚集体。
