Influence of polyelectrolyte charge density on the formation of multilayers of strong polyelectrolytes at low ionic strength
Influence of polyelectrolyte charge density on the formation of multilayers of strong polyelectrolytes at low ionic strength
复制标题
低离子强度下聚电解质电荷密度对强聚电解质多层形成的影响
DOI：
10.1021/la0113670
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发表时间：
2002
期刊：
影响因子：
3.9
通讯作者：
A. Laschewsky
中科院分区：
文献类型：
--
作者：
K. Glinel;A. Moussa;A. Jonas;A. Laschewsky
研究了聚电解质电荷密度对纯水溶液中逐层自组装聚电解质多层膜生长的影响。多层膜由强聚阴离子（即聚苯乙烯磺酸盐）和剥落的合成锂蒙脱石以及二烯丙基二甲基氯化铵（DADMAC）与N-甲基-N-乙烯基甲酰胺（NMVF）的阳离子共聚物构建而成，其组成和电荷密度都有系统地变化。对体系{阳离子共聚物/聚(苯乙烯磺酸盐)}的分析表明，为了在纯水中获得稳定的多层生长，需要0.036基本电荷/埃等高线长度的临界线性电荷密度lambda(c)。高于 lambda(c) 时，厚度/沉积周期的增量随阳离子共聚物的线性电荷密度变化，与聚电解质溶液的当前理论非常一致。随着线性电荷密度的增加，系统连续通过电荷相关的“德拜-休克尔”状态，然后通过与电荷无关的“强屏蔽”状态，其中反离子凝聚主导行为。对于内部结构杂化多层{阳离子共聚物/锂蒙脱石}的基底间距的变化，获得了类似的结果。然而，与第一个系统相比，混合系统没有发现临界线性电荷密度。这是通过粘土片晶和甲酰胺片段之间额外的非静电相互作用来解释的。
The influence of the charge density of polyelectrolytes on the growth of polyelectrolyte multilayers via layer-by-layer self-assembly from pure aqueous solutions was studied. Multilayers were built from strong polyanions, namely poly(styrenesulfonate) and an exfoliated synthetic hectorite, and cationic copolymers of diallyldimethylammonium chloride (DADMAC) with N-methyl-N-vinylformamide (NMVF) for which the composition and thus the charge density was varied systematically. The analysis of the system {cationic copolymer/poly(styrenesulfonate)} reveals that a critical linear charge density lambda(c) of 0.036 elementary charge/Angstrom of contour length is necessary to obtain stable multilayer growth in pure water. Above lambda(c) the increment of thickness/deposition cycle varies with the linear charge density of the cationic copolymers, in good agreement with current theories of polyelectrolyte solutions. As linear charge density increases, the system passes successively through a charge-dependent "Debye-Huckel" regime and then through a charge-independent "strong-screening" regime where counterion condensation dominates the behavior. Analogous results were obtained for the variation of the basal spacing of internally structured hybrid multilayers {cationic copolymer/hectorite}. However, by contrast with the first system, no critical linear charge density was found for the hybrid system. This is explained by additional, nonelectrostatic interactions between the clay platelets and the formamide fragment.