Preparation and characterization of polyelectrolyte-coated gold nanoparticles
Preparation and characterization of polyelectrolyte-coated gold nanoparticles
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DOI：
10.1021/la703003m
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发表时间：
2008-03-18
期刊：
影响因子：
3.9
通讯作者：
Lennox, R. Bruce
中科院分区：
文献类型：
--
作者：
Dorris, Annie;Rucareanu, Simona;Lennox, R. Bruce
采用静电自组装技术，在4-二甲氨基吡啶（DMAP）稳定的5 nm金纳米粒子表面包覆聚对苯乙烯磺酸钠（PSS）。通过改变pH、PSS链长和PSS浓度，研究了由金表面等离子体带（SPB）监测的悬浮液稳定性。当聚合物链长匹配或超过颗粒周长时，在pH 10（高于DMAP的pK（a））下获得增强的稳定性。固态C-13 NMR用于确定在随后沉积弱聚阳离子和强聚阳离子后DMAP和聚合物的存在：聚（烯丙基胺盐酸盐）（PAH）和聚（二烯丙基二甲基氯化铵）（PDADMAC）。在pH 10下，DMAP在第一PSS层已经形成之后保持与纳米颗粒缔合。当随后在pH 4.5下加入PAH或PDADMAC时，排出DMAP，悬浮液保持稳定，并且ζ电位值指示完全电荷反转。然而，在PDADMAC的情况下，PSS的第一层没有被完全保留。当在pH 10下加入PDADMAC时，DMAP和第一PSS层被保留，但较低的ζ电位和较高的ζ位移表明稳定性降低。对于pH 9.5的PAH添加，DMAP和PSS都被排出，并且悬浮液变得不稳定。多层组分和纳米颗粒悬浮液的稳定性的这些差异在链柔性、聚合物电荷密度和聚合物官能团直接与金表面相互作用的能力方面是合理的。
Gold nanoparticles of 5 nm diameter, stabilized by 4-(dimethylamino)pyridine (DMAP), were coated with poly(sodium 4-styrene sulfonate) (PSS) via electrostatic self-assembly. The suspension stability, monitored by the gold surface plasmon band (SPB), was studied by varying the pH, the PSS chain length, and PSS concentration. Enhanced stability is obtained at pH 10 (above the pK(a) of DMAP) when the polymer chain length matches or exceeds the particle circumference. Solid state C-13 NMR was used to determine the presence of DMAP and polymers after subsequent deposition of weak and strong polycations: poly(allylamine hydrochloride) (PAH) and poly(diallyldimethylammonium chloride) (PDADMAC). At pH 10, DMAP remains associated with the nanoparticle after the first PSS layer has been formed. When PAH or PDADMAC are subsequently added at pH 4.5, DMAP is expelled, the suspensions remain stable, and zeta potential values indicate complete charge reversal. In the case of PDADMAC, however, the first layer of PSS is not fully retained. When PDADMAC is added at pH 10, DMAP and the first PSS layer are retained but lower zeta potentials and a higher SOB shift indicate a degraded stability. For PAH addition at pH 9.5, both DMAP and PSS are expelled and the suspension becomes unstable. These differences in stability of the multilayer components and the nanoparticle suspension are rationalized in terms of chain flexibility, polymer charge density, and the ability of the polymer functional groups to directly interact with the gold surface.