Polyelectrolyte Adsorption on a Charged Surface. A Study by Monte Carlo Simulations
Polyelectrolyte Adsorption on a Charged Surface. A Study by Monte Carlo Simulations
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DOI：
10.1021/ma0705568
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发表时间：
2007-09
期刊：
影响因子：
5.5
通讯作者：
C. Narambuena;D. Beltramo;E. Leiva
中科院分区：
文献类型：
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作者：
C. Narambuena;D. Beltramo;E. Leiva
在本工作中，我们利用聚电解质和离子的原始模型，建立了聚电解质（PE）在带电表面上吸附的大规范蒙特卡罗研究。通过使用仅保留静电相互作用的模型，获得了PE吸附时的电荷反转。计算了吸附过程的自由能变化，并分析了对该量的不同贡献。其中考虑了离子释放引起的熵增益、PE的构象变化和焓变化。结果表明，熵的贡献是这种现象的驱动力，源于PE和带电表面的双层反离子的释放。所得到的正焓值根据吸附后离子对数量的减少而合理化。
In the present work, we develop a grand canonical Monte Carlo study of polyelectrolyte (PE) adsorption on a charged surface by means of a primitive model for the PE and the ions. Charge reversal upon PE adsorption was obtained by using a model that only retains the electrostatic interactions. Free energy changes for the adsorption process were calculated and different contributions to this quantity were analyzed. Among them, the entropic gain due to ion release, the conformational changes of the PE, and enthalpic changes were considered. The results suggest that the entropic contribution is the driving force of this phenomenon, stemming from the release of counterions from the double layers of the PE and the charged surface. The positive enthalpy value obtained is rationalized in terms of the decrease of the number of ionic pairs upon adsorption.