Tapping mode atomic force microscopy investigation of poly(amidoamine) dendrimers: Effects of substrate and pH on dendrimer deformation
Tapping mode atomic force microscopy investigation of poly(amidoamine) dendrimers: Effects of substrate and pH on dendrimer deformation
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DOI：
10.1021/la001297h
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发表时间：
2001-05-01
期刊：
影响因子：
3.9
通讯作者：
Baker, JR
中科院分区：
文献类型：
--
作者：
Betley, TA;Holl, MMB;Baker, JR
基板的影响，体积再现性，乙二胺核心聚（酰胺胺）树枝状聚合物（第6-9代）的大小和形状的pH值的影响进行了探讨，使用轻敲模式原子力显微镜（AFM）测量。测量结果的统计分析表明，使用相同头端重复测量的体积变化为4%。探讨了通过数值积分和球冠估计法确定体积的方法。球冠模型被证明高估了树枝状大分子体积的一个因素，类似于2。由于基板从云母更疏水的表面，AFM测量的高度和直径接近理想球树枝状聚合物的直径。第6-9代树枝状聚合物样品的酸化导致观察到体积增加33%，高度增加26%，直径减小9%。酸化后的膨胀可归因于电荷分离的最大化和树枝状聚合物内溶剂保留的增加。使用碳纳米探针增强二维簇内的单个树枝状聚合物分辨率。
Substrate effects, volume reproducibility, and pH effects on the size and shape of ethylenediamine core poly(amidoamine) dendrimers (generations 6-9)were explored using tapping mode atomic force microscopy (AFM) measurements. A statistical analysis of the measurements indicated a 4% variation in volume for repeated measurement using the same tip. Volume determinations by numerical integration and a spherical cap estimation method were explored. The spherical cap model was shown to overestimate dendrimer volumes by a factor of similar to2. As substrates were changed from mica to more hydrophobic surfaces, AFM-measured heights and diameters approached ideal-sphere dendrimer diameters. Acidification of dendrimer samples from generations 6-9 led to an observed 33% increase in volume, 26% increase in height, and 9% decrease in diameter. Expansion upon acidification can be attributed to maximization of charge separation and increased solvent retention within the dendrimers. Single dendrimer resolution within two-dimensional clusters was enhanced using carbon nanoprobes.