Modeling the Buildup of Exponentially Growing Polyelectrolyte Multilayer Films
Modeling the Buildup of Exponentially Growing Polyelectrolyte Multilayer Films
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DOI：
10.1021/jp809959j
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发表时间：
2009-04-02
影响因子：
3.3
通讯作者：
Larson, Ronald G.
中科院分区：
文献类型：
--
作者：
Hoda, Nazish;Larson, Ronald G.
我们开发了一个简化的一维模型来描述指数增长的迁移聚阳离子的膜，多层膜的建立和出。该模型占在膜表面的能量势垒的存在下，和膜溶解。所有的静电相互作用，使用屏蔽库仑势建模。对于适当选择的模型参数，模型预测与实验结果定量一致。该模型预测，指数到线性的增长过渡设置动力学，这种过渡发生时，浸渍时间不足以使未结合的聚阳离子均匀分布在膜内。另外，对于表现出指数增长的膜，在浸入聚阳离子溶液之后的冲洗步骤期间，非常少的未结合的聚阳离子移出膜是必要的。该模型预测，这一标准是满足时，尖锐的峰值能量障碍是存在于膜表面或当膜溶胀。此外，该模型预测，当浸渍时间t（d）与H2成比例增加时，只要k（d）t（d），薄膜将呈指数增长，其中H是薄膜厚度
We develop a simplified one-dimensional model to describe the build-up of exponentially growing migration of polycations in and out of the film, polyelectrolyte multilayer films. The model accounts for the In the existence of an energetic barrier at the film surface, and film dissolution. All the electrostatic interactions are modeled using a screened Coulombic potential. For appropriately chosen model parameters, the model predictions are in quantitative agreement with experimental results. The model predicts that the exponential-to-linear growth transition is set kinetically, and this transition occurs when the dipping time is not long enough for unbound polycations to uniformly distribute inside the film. Additionally, for a film to exhibit exponential growth, it is essential that very few unbound polycations move out of the film during the rinsing step that follows after dipping in a solution of polycations. The model predicts that this criterion is satisfied either when a sharply peaked energetic barrier is present at the film surface or when the film swells. Furthermore, the model predicts that when dipping time, t(d), is increased proportionally with H 2, where H is the film thickness, the film will grow exponentially as long as k(d)t(d)