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首页> 外文期刊>The journal of physical chemistry, B. Condensed matter, materials, surfaces, interfaces & biophysical >Temperature-Induced Transition from Odd-Even to Even-Odd Effect in Polyelectrolyte Multilayers Due to Interpolyelectrolyte Interactions
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Temperature-Induced Transition from Odd-Even to Even-Odd Effect in Polyelectrolyte Multilayers Due to Interpolyelectrolyte Interactions

机译：由于聚电解质间的相互作用，温度引起的聚电解质多层中的奇偶效应跃迁到奇偶效应

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摘要

Within a liquid cell the linear growth of polyelectrolyte multilayers from poly(styrenesulfQnate) (PSS) and poly(ally!amine hydrochloride) (PAH) is observed with multiple angle null ellipsometry. The salt content is varied between 1 and 4 mol/L NaCl and the temperature between 20 and 55 °C. In the linear growth regime, the outermost layer is investigated. At low temperature, a top PSS layer is twice as thick as a top PAH layer (odd-even effect), consistent with the respective monomer volumes and the same water content for both kinds of top polyelectrolyte layers as confirmed by refractive indexmeasurements. On heating, the thickness of a polycation/polyanion bilayer increases. For temperatures exceeding a crossover temperature, a top PAH layer is thicker than a top PSS layer (even-odd effect). Simultaneously, the index of refraction of the respective top layers indicates a compact PSS and a swollen PAH layer. It is suggested that, at elevated temperature and high salt conditions, secondary forces gain importance in comparison to electrostatic forces: therefore, a transition from an odd-even to an even-odd elfect occurs, as well as the decreased film stability on drying as described before (Cornelsen, M., et al. Macromolecules 2010,43,4.300). The ellipsometric data indicate that PAH/PSS layer pairs exceeding 8.6 nm thickness in solution are unstable in air.
机译：在液体池中，通过多角度零椭偏法观察到了由聚（苯乙烯磺酸盐）（PSS）和聚（烯丙胺盐酸盐）（PAH）形成的聚电解质多层的线性生长。盐含量在1-4 mol / L NaCl之间变化，温度在20到55°C之间变化。在线性生长方式中，研究了最外层。在低温下，顶层PSS层的厚度是顶层PAH层的两倍（奇数效应），这与两种顶层聚电解质层的相应单体体积和相同的水含量一致，这已通过折射率测量得到了证实。加热时，聚阳离子/聚阴离子双层的厚度增加。对于超过交叉温度的温度，PAH顶层比PSS顶层更厚（奇数效果）。同时，各个顶层的折射率表示致密的PSS和溶胀的PAH层。建议在高温和高盐度条件下，与静电力相比，次级力变得更为重要：因此，会发生从奇数到奇数的过渡，以及干燥时膜稳定性下降。 （例如，Cornelsen，M。，等人，Macromolecules 2010，43，4.300）。椭偏数据表明，溶液中厚度超过8.6 nm的PAH / PSS层对在空气中不稳定。

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