Impact of Molecular Structure on Zeta Potential and Adsorbed Conformation of α-Allyl-ω-Methoxypolyethylene Glycol - Maleic Anhydride Superplasticizers
Impact of Molecular Structure on Zeta Potential and Adsorbed Conformation of α-Allyl-ω-Methoxypolyethylene Glycol - Maleic Anhydride Superplasticizers
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DOI：
10.3151/jact.4.233
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发表时间：
2006
影响因子：
2
通讯作者：
J. Plank;B. Sachsenhauser
中科院分区：
文献类型：
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作者：
J. Plank;B. Sachsenhauser
合成了侧链长度nEO为0-130的α-烯丙基-ω-甲氧基聚乙二醇-马来酸酐共聚物，并通过水性GPC进行了表征。开发了它们的分子构象（例如蠕虫状、刷状或星状聚合物）的表示。随着侧链长度nEO的增加，水泥上吸附的聚合物量迅速减少。使用电声方法在 w/c = 0.5 的水泥浆中进行 Zeta 电位测量表明，nEO ≤ 7 的蠕虫状共聚物平坦吸附（“火车”型）并形成致密的聚合物薄膜。在这种情况下，共聚物的吸附量高。对于 nEO ≥ 34 的星形聚合物，聚合物主链的优先取向垂直于水泥表面（“尾”型）。结果是形成厚聚合物层，顶部有第二个电化学双层。对于星形聚合物，由于水平层状侧基的表面占有率较高，吸附量较低。
α-Allyl-ω-methoxypolyethylene glycol - maleic anhydride copolymers were synthesized with side chain lengths nEO from 0-130 and characterized by aqueous GPC. A representation of their molecular conformation (e.g. worm-, brush- or star-like polymers) was developed. The amount of polymer adsorbed on cement rapidly decreases with increasing side chain length nEO. Zeta potential measurements using the electroacoustic method in cement paste with w/c = 0.5 indicate that worm-like copolymers with nEO ≤ 7 adsorb flat (“train” type) and form a densely packed, thin polymer film. In this case, the adsorbed amount of copolymer is high. For star polymers with nEO ≥ 34, preferred orientation of the polymer main chain is perpendicular to the cement surface (“tail” type). The result is a thick polymer layer, with a second electrochemical double layer on top. For star polymers, the adsorbed amount is low because of the higher surface occupancy of horizontally layered side groups.