Rheology of Dendrimers. I. Newtonian Flow Behavior of Medium and Highly Concentrated Solutions of Polyamidoamine (PAMAM) Dendrimers in Ethylenediamine (EDA) Solvent
Rheology of Dendrimers. I. Newtonian Flow Behavior of Medium and Highly Concentrated Solutions of Polyamidoamine (PAMAM) Dendrimers in Ethylenediamine (EDA) Solvent
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DOI：
10.1021/ma971199b
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发表时间：
1998-06
期刊：
影响因子：
5.5
通讯作者：
S. Uppuluri;Steven E. Keinath;A. Tomalia;P. Dvornic
中科院分区：
文献类型：
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作者：
S. Uppuluri;Steven E. Keinath;A. Tomalia;P. Dvornic
稳定的剪切流动性能的一个广泛的家庭的树枝状聚合物首次在中高浓度的解决方案进行了检查。为此，使用了前七代乙二胺（EDA）核-聚酰胺胺（PAMAM）树枝状聚合物，其在乙二胺（EDA）中的30至75重量%溶液中具有约500至几乎60 000的分子量。发现这些树枝状聚合物溶液表现出典型的牛顿流动行为，如剪切应力与剪切速率成正比（即，相对于剪切应力和剪切速率的恒定粘度）。除此之外，剪切粘度与分子量关系的斜率没有突然变化，这表明这些树枝状聚合物不会相互渗透形成长链线性或随机支化大分子通常存在的“缠结”类型的瞬态准网络，也不参与“粘附”相互作用。
Steady shear flow properties of an extensive family of dendrimers were examined for the first time in medium to high concentration solutions. For this, the first seven generations of ethylenediamine (EDA) core−polyamidoamine (PAMAM) dendrimers, having molecular weights from about 500 to almost 60 000 in 30 to 75 wt % solutions in ethylenediamine (EDA) were used. It was found that these dendrimer solutions exhibited typical Newtonian flow behavior as manifested by direct proportionality of the shear stress to the shear rate (i.e., constant viscosity with respect to both shear stress and shear rate) over the entire range of shear stress and shear rate studied. In addition to this, there was no abrupt change in the slope of the shear viscosity vs molecular weight relationship, indicating that these dendrimers do not interpenetrate to form transient quasi-networks of the “entanglement”-type typically found for long-chain linear or randomly branched macromolecules, nor do they engage in “sticking” interactions...