Resolving the Difference in Electric Potential within a Charged Macromolecule
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- 作者：Shuangjiang Luo ; Xiubo Jiang ; Lei Zou ; Fei Wang ; Jingfa Yang ; Yongming Chen ; Jiang Zhao
- 刊名：Macromolecules
- 出版年：2013
- 出版时间：April 23, 2013
- 年：2013
- 卷：46
- 期：8
- 页码：3132-3136
- 全文大小：259K
- 年卷期：v.46,no.8(April 23, 2013)
- ISSN：1520-5835
文摘
The difference of the electric potential between the middle and end of polystyrenesulfonate (PSS鈥?/sup>) chain is discovered experimentally. Using a pH-responsive fluorophore attached to these two locations on the PSS鈥?/sup> chain, the local pH value was determined by single molecule fluorescence technique: photon counting histogram (PCH). By the observation of a very high accumulation of proton (2鈥? orders of magnitude in concentration) at the vicinity of the PSS鈥?/sup> as a result of the electrostatic attraction between the charged chain and protons, the electric potential of the PSS鈥?/sup> chain is determined. A higher extent of counterion adsorption is discovered at the middle of the PSS鈥?/sup> chain than the chain end. The entropy effect of the counterion adsorption is also discovered鈥攗pon the dilution of protons, previously adsorbed counterions are detached from the chain.