Division of Surface and Interface Science, Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz, Austria.
Langmuir. 2013 Jul 9;29(27):8544-53. doi: 10.1021/la400880a. Epub 2013 Jun 25.
This study focuses on the investigation of the influence of the ionic strength on the internal structure, film forming behavior, and swelling properties of polyelectrolyte/clay multilayers. Layer-by-layer films were prepared with three different polyelectrolytes [polyethylenimine (PEI), polydiallyldimethylammoniumchloride (pDADMAC), and 2-hydroxy-3-trimethylammonium propyl chloride starch (HPMA starch)] in combination with laponite clay platelets on three different surfaces. All experiments were carried out at two different ionic strengths (30 mM or 500 mM NaCl). The experiments performed with strong polyelectrolytes revealed a higher film thickness and adsorbed masses of clay and polyelectrolyte at 500 mM NaCl. The films containing PEI showed different behavior and were considerably less sensitive to changes in the ionic strength. This was also reflected by the swelling behavior as demonstrated by quartz crystal microbalance with dissipation (QCM-D) measurements. Films comprising PEI showed, in contrast to the other polyelectrolytes, much lower swelling in water leading to more compact and stable films in humid environments which is important for numerous applications of LbL clay coatings.
本研究专注于研究离子强度对聚电解质/粘土多层膜的内部结构、成膜行为和溶胀性能的影响。使用三种不同的聚电解质[聚乙烯亚胺（PEI）、聚二烯丙基二甲基氯化铵（pDADMAC）和 2-羟基-3-三甲基铵丙基氯化淀粉（HPMA 淀粉）]与皂土片层在三种不同的表面上制备了层层膜。所有实验均在两种不同的离子强度（30 mM 或 500 mM NaCl）下进行。在强聚电解质存在下进行的实验表明，在 500 mM NaCl 下，膜的厚度和粘土及聚电解质的吸附量更高。含有 PEI 的膜表现出不同的行为，对离子强度的变化不太敏感。这也反映在石英晶体微天平耗散（QCM-D）测量中所展示的溶胀行为上。与其他聚电解质相比，包含 PEI 的膜在水中的溶胀率较低，导致在潮湿环境中形成更紧凑和稳定的膜，这对于 LbL 粘土涂层的众多应用非常重要。
