Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
Langmuir. 2009 Dec 15;25(24):13874-9. doi: 10.1021/la901270x.
Gold nanoparticles were synthesized using a seed-mediated wet chemical approach with a polymerizable surfactant, 11-(acryloyloxy)undecyltrimethylammonium bromide. The polymerizable surfactant forms a bilayer on the surface of the gold nanoparticles with the quaternary positive head groups facing the bulk water, and the polymerizable groups reside in the hydrophobic region. Evidence for on-particle polymerization using a cationic free radical initiator was confirmed by NMR and FTIR analyses. Ultraviolet-visible spectroscopy, transmission electron microscopy, and dynamic light scattering measurements showed no particle aggregation after polymerization. In contrast to the nanoparticles before polymerization, the nanoparticles with a polymerized bilayer showed remarkable stability against dialysis, centrifugation-resuspension cycles, and extraction with organic solvent. This enhanced stability was linked to the decrease in surfactant desorption from the surface of the gold nanoparticles as evident from mass spectrometry analysis of supernatants. Our results indicate that the use of a polymerizable surfactant as a directing agent to prepare gold nanoparticles and subsequent "fixing" the surfactant bilayer by polymerization is an effective approach to enhance the stability of the final nanoparticles.
采用种子介导的湿化学方法，使用可聚合的表面活性剂 11-（丙烯酰氧基）十一烷基三甲基溴化铵合成了金纳米粒子。可聚合的表面活性剂在金纳米粒子表面形成双层，带正电荷的季铵头基朝向本体水，可聚合基团位于疏水区。使用阳离子自由基引发剂在颗粒上聚合的证据通过 NMR 和 FTIR 分析得到了证实。紫外-可见光谱、透射电子显微镜和动态光散射测量表明聚合后没有颗粒聚集。与聚合前的纳米粒子相比，具有聚合双层的纳米粒子对透析、离心-再悬浮循环和有机溶剂萃取具有显著的稳定性。这种增强的稳定性与从金纳米粒子表面解吸表面活性剂的减少有关，这从上清液的质谱分析中可以明显看出。我们的结果表明，使用可聚合的表面活性剂作为导向剂来制备金纳米粒子，然后通过聚合“固定”表面活性剂双层，是提高最终纳米粒子稳定性的有效方法。
