کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5181116 1380953 2014 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Polyelectrolyte brushes in monovalent and multivalent salt solutions
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
Polyelectrolyte brushes in monovalent and multivalent salt solutions
چکیده انگلیسی

Langevin dynamics simulations are performed to study polyelectrolyte brushes by varying the chain grafting density σg, the added salt valence Z, and concentration Cs. The brush thickness H follows a scaling relation in monovalent salt solutions as Cs−0.15, decreasing more slowly than the scaling prediction. In divalent and trivalent salt solutions, H acquires a minimum value at the stoichiometric point, and then levels off and slightly increases, respectively. The shape and orientation of the chains change with Cs accordingly. An electric double layer is formed around the brush rim, revealed by the calculation of vertical charge distribution. Increasing σg, Z, Cs reduces the width of the layer. Side-view density study further shows how the three parameters transform the brush profile from an individual-chain distribution to a homogeneous one. Finally, about 90% of chain charges are neutralized by the ions trapped in the brushes. It is found that ion condensation on the chains can be described by Manning's theory in sparse grafting and dilute salt conditions.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 55, Issue 12, 6 June 2014, Pages 2900-2912
نویسندگان
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