Using Thiol–Gold Bond Formation To Bridge Surfaces with a Polymer Brush: SFA Experiments and MD Simulations
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- 作者：Suzanne M. Balko ; Torsten Kreer ; Dennis J. Mulder ; Philip J. Costanzo ; Timothy E. Patten ; Tonya L. Kuhl
- 刊名：Macromolecules
- 出版年：2013
- 出版时间：December 23, 2013
- 年：2013
- 卷：46
- 期：24
- 页码：9826-9836
- 全文大小：644K
- ISSN：1520-5835
文摘
Complementary interactions between functionalized surfaces are challenging to quantify, as both kinetics and thermodynamics are important. Optimal reaction parameters are key to the efficient formation of hierarchical nanostructures. Here, we report both surface forces apparatus (SFA) studies and molecular dynamics (MD) simulations of the controlled binding of thiol functionalized polymer brushes to complementary gold surfaces. Polymer brush鈥揵rush, brush鈥搈ica, and brush鈥揼old experiments were performed in toluene. These comparative studies reveal the subtle balance of nonspecific and specific contributions to the measured interactions. Importantly, the physical phenomena responsible for the measured force profile in the selective binding system, including the formation of thiol鈥揼old bonds, the resulting adhesion between the surfaces, the work to separate the surfaces, and the anchor strength of the polymer brush can be extracted. Corroborating MD simulations demonstrate that hysteresis in the approach and separation of these selectively bound surfaces is not the result of kinetic effects, but rather is due to the polydispersity of the brush itself and the resulting thiolated chain end distribution. We relate our findings to observations made in the formation of hierarchical particle aggregates.