Controlling surface properties of polyelectrolyte multilayers by assembly pH.
Controlling surface properties of polyelectrolyte multilayers by assembly pH.
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DOI：
10.1039/c3cp51556g
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发表时间：
2013-06
期刊：
影响因子：
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通讯作者：
Xiao Gong
中科院分区：
文献类型：
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作者：
Xiao Gong
以聚（二烯丙基二甲基氯化铵）（PDADMAC）和聚（4-苯乙烯磺酸-co-马来酸，1：1 SS：MA）钠盐（PSSMA 1：1）为构建单元，通过调节组装pH值，对多层膜的表面性质如形貌、粗糙度、刚度和润湿性进行了控制。我们发现，随着组装pH值的增加，多层膜的表面粗糙度增加，并且当PSSMA组装为最终层时，在不同的组装pH值下，多层膜的形貌有很大的不同。然而，多层膜（PDADMAC作为最终层）的表面粗糙度和形态在各种组装pH值下没有表现出明显的变化。有趣的是，PSSMA/PDADMAC多层膜的刚度可以调节。纳米压痕测量结果表明，在不同的pH值时，PSSMA是最外层的多层膜的硬度是非常不同的。相反，当PDADMAC是最外层时，多层膜的硬度保持不变，无论pH值如何。水接触角滞后（前进和后退接触角之间的差异）的多层膜在很大程度上受到表面粗糙度和表面亲水基团，也可以通过组装pH值进行调整。
The control of surface properties such as the morphology, roughness, stiffness, and wettability of polyelectrolyte multilayers was carried out using poly(diallyldimethylammonium chloride) (PDADMAC) and poly(4-styrenesulfonic acid-co-maleic acid, 1 : 1 SS : MA) sodium salt (PSSMA 1 : 1) as the building blocks via adjusting the assembly pH value. We found that the surface roughness of the multilayers increased with increasing assembly pH value, and that the morphology was quite different at various assembly pH values when PSSMA was assembled as the final layer. However, the surface roughness and morphology of the multilayers (PDADMAC as the final layer) showed no apparent change at various assembly pH values. Interestingly, the stiffness of the PSSMA/PDADMAC multilayers could be tuned. Nanoindentation measurements by SFM showed that the hardness of the multilayers was very different at various pH values when PSSMA was the outermost layer. Conversely, the hardness of the multilayers remained unchanged regardless of the pH when PDADMAC was the outermost layer. The water contact angle hysteresis (the difference between the advancing and receding contact angles) of the multilayers was largely affected by both surface roughness and surface hydrophilic groups which could also be tuned by assembly pH.