Department of Chemistry and Pharmacy and Interdisciplinary Center for Molecular Materials, Friedrich-Alexander-University Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany.
J Phys Chem B. 2010 Dec 2;114(47):15466-76. doi: 10.1021/jp107358q. Epub 2010 Nov 5.
This article focuses on the physical chemical aspects of the formation of supramolecular nanoparticles with defined size and varying shape through electrostatic self-assembly of macroions and multivalent aromatic counterions. For cationic poly(amidoamine) dendrimers and different di- and trivalent sulfonate groups carrying azo dyes, the onset of interdendrimer connection and assembly size (hydrodynamic radius 20 nm < R(h) < 150 nm) depend on counterion/macroion loading ratio. Centrifugation and dialysis experiments show assemblies coexisting with individual dye-loaded dendrimers with lower dye/dendrimer ratio at small loading ratio, while around charge stoichiometry only assemblies are present. Zeta-potential measurements reveal a positive charge for samples with excess dendrimer. For excess dye, overloading to negatively charged assemblies is possible for some dyes, which is consistent with concentration-dependent stability revealing a second mode of more loosely bound dye ions. Kinetic versus thermodynamic effects are discussed based on varying the preparation route. The interaction enthalpy is an important factor in determining assembly size. Solution structures are characterized by static and dynamic light scattering, while atomic force microscopy showed that assemblies can also be deposited on surfaces.
本文主要关注通过大分子离子和多价芳香抗衡离子的静电自组装形成具有确定尺寸和变化形状的超分子纳米粒子的物理化学方面。对于阳离子聚（酰胺-胺）树状大分子和不同的二价和三价磺酸盐基团负载偶氮染料，树突大分子之间连接和组装尺寸（流体力学半径 20nm<R(h)<150nm）的出现取决于抗衡离子/大分子的装载比。离心和透析实验表明，在装载比较低时，组装体与染料负载较低的单个树突大分子共存，而在接近电荷化学计量比时，仅存在组装体。Zeta 电位测量显示，对于具有过量树突大分子的样品，带有正电荷。对于一些染料，可以对过量染料进行超负载，形成带负电荷的组装体，这与浓度依赖性稳定性一致，表明存在第二种更松散结合的染料离子模式。基于改变制备路线，讨论了动力学与热力学效应。相互作用焓是决定组装体尺寸的一个重要因素。溶液结构通过静态和动态光散射进行表征，而原子力显微镜显示组装体也可以沉积在表面上。
