Universite de Bordeaux, CNRS, Centre de Recherche Paul Pascal, Avenue Schweitzer, 33600 Pessac, France.
Langmuir. 2009 Nov 17;25(22):13206-11. doi: 10.1021/la9018822.
We present a detailed study of the influence of pH on the dispersion and film-forming properties of poly(acrylic acid)-stabilized carbon nanotubes. Poly(acrylic acid) (PAA) is a weak polyelectrolyte, with a pH-responsive behavior in aqueous solution. We obtain quantitative UV-visible measurements to show that the amount of polyelectrolyte in optimal pH conditions is weak, showing a good efficiency of the polymer as a carbon nanotube dispersing agent. The best dispersion conditions are achieved at pH 5, a value close to the pK(a) of PAA. Apart from this tenuous pH value, the PAA is not efficient at stabilizing nanotubes and atomic force microscopy allows us to explain the delicate balance between the PAA adsorption and the suspension stability. This study finally permits optimal conditions for making homogeneous and conductive composite films to be determined.
我们详细研究了 pH 值对聚（丙烯酸）稳定的碳纳米管分散和成膜性能的影响。聚（丙烯酸）（PAA）是一种弱聚电解质，在水溶液中具有 pH 值响应行为。我们获得了定量的紫外-可见测量结果，表明在最佳 pH 值条件下的聚电解质数量较弱，表明聚合物作为碳纳米管分散剂的效率很高。最佳分散条件在 pH 值为 5 时达到，接近 PAA 的 pK(a)值。除了这个微弱的 pH 值之外，PAA 对稳定纳米管的效率不高，原子力显微镜使我们能够解释 PAA 吸附和悬浮稳定性之间的微妙平衡。这项研究最终确定了制备均匀和导电复合膜的最佳条件。
