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. 2011 Aug 18;115(32):9710-9. doi: 10.1021/jp204368t. Epub 2011 Jul 22.
This study describes the influence of polyelectrolyte building block nature on the formation of supramolecular polyelectrolyte-dye nanoparticles self-assembled through electrostatic interactions of the oppositely charged building units and π-π interactions in-between dye molecules ("electrostatic self-assembly"). The anionic azo dye Acid Red 26 (Ar26) is combined with cationic polyamidoamine dendrimers of generations G0, G2, G4, G6, and G8 and linear polycations polylysine (PolyLys) and polyallylamine hydrochloride (PAH). Light scattering reveals defined supramolecular particles with hydrodynamic radii R(H) = 15 nm to R(H) = 50 nm for slight excess of G2-G8 dendrimers. G0 does not yield stable assemblies. Linear polyelectrolytes form assemblies with hydrodynamic radii from R(H) = 20 nm to R(H) = 200 nm. Thermodynamic measurements by isothermal titration calorimetry (ITC) show that all macroions bind dye molecules up to about charge stoichiometry, and assembly formation is predominantly enthalpically driven. Differences in dye-dye interactions are related to structural features by analyzing endothermic heats of aggregate disruption through excess macroion addition. A simple model connects thermodynamic parameters with the internal assembly structure.
本研究描述了聚电解质构筑基元性质对通过带相反电荷构筑单元的静电相互作用和染料分子间的π-π相互作用自组装形成超分子聚电解质-染料纳米粒子的影响（“静电自组装”）。阴离子偶氮染料酸性红 26（Ar26）与阳离子聚酰胺胺树枝状大分子 G0、G2、G4、G6 和 G8 以及线性聚阳离子聚赖氨酸（PolyLys）和聚烯丙胺盐酸盐（PAH）结合。光散射显示出具有定义的超分子粒子，其流体力学半径 R（H）为 15nm 至 50nm，对于 G2-G8 树枝状大分子的轻微过量。G0 不会产生稳定的组装体。线性聚电解质形成流体力学半径为 R（H）= 20nm 至 R（H）= 200nm 的组装体。通过等温滴定量热法（ITC）进行的热力学测量表明，所有大分子都结合了染料分子，直到大约达到电荷化学计量比，并且组装形成主要是由焓驱动的。通过分析通过过量大分子添加引起的聚集体破坏的吸热焓，将染料-染料相互作用的差异与结构特征相关联。一个简单的模型将热力学参数与内部组装结构联系起来。
