BioPRIA, Australian Pulp and Paper Institute (APPI), Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia.
J Colloid Interface Sci. 2013 Sep 1;405:71-7. doi: 10.1016/j.jcis.2013.05.011. Epub 2013 May 17.
This work reports a simple method to form and visualize individual polyelectrolyte-nanoparticle necklace-like structures on paper, which is applicable to other porous surfaces. In this work, one-dimensional necklaces of negatively charged gold nanoparticles (AuNPs) have been electrostatically assembled along the backbone of a cationic polyacrylamide (CPAM) chain adsorbed on paper. The process involves rapidly passing a dilute CPAM solution through filter paper, adsorbing the polyelectrolyte on the surface, followed by the immediate filtration of an AuNP suspension through the same filter paper. The nanoparticles used were negatively charged, citrate ion capped AuNPs with an average diameter of 20 nm. Scanning electron microscopy images of the dried paper sample showed that the AuNP necklaces were adsorbed in a perpendicular direction to that of the cellulose fibers and along the length of the CPAM molecules which were draped over the fibers. The effects of CPAM polymer concentration, charge density, and molecular weight on such assembly of AuNPs were studied. This technique enables the visualization of polyelectrolyte molecules and the formation of very well organized and reproducible polyelectrolyte-nanoparticle necklaces on a porous, three-dimensional substrate.
这项工作报道了一种在纸上形成和可视化单个聚电解质-纳米粒子项链状结构的简单方法，该方法也适用于其他多孔表面。在这项工作中，带负电荷的金纳米粒子（AuNP）的一维项链通过阳离子聚丙烯酰胺（CPAM）链在滤纸表面上的静电组装沿着 CPAM 链的主链排列。该过程包括快速通过滤纸传递稀释的 CPAM 溶液，在表面上吸附聚电解质，然后立即通过相同的滤纸过滤 AuNP 悬浮液。所用的纳米粒子是带负电荷的、柠檬酸根离子封端的 AuNP，平均直径为 20nm。干燥滤纸样品的扫描电子显微镜图像显示，AuNP 项链以垂直于纤维素纤维的方向和沿着 CPAM 分子的长度被吸附，CPAM 分子覆盖在纤维上。研究了 CPAM 聚合物浓度、电荷密度和分子量对这种 AuNP 组装的影响。该技术能够可视化聚电解质分子，并在多孔三维基底上形成非常有序且可重复的聚电解质-纳米粒子项链。
