期刊
ACS NANO
卷 7, 期 11, 页码 9735-9742出版社
AMER CHEMICAL SOC
DOI: 10.1021/nn4049039
关键词
single-molecule fluorescence imaging; polymer adsorption/desorption; surface diffusion; jump; truncated Levy distribution
类别
资金
- U.S. through the National Science Foundation (Polymers Program) [DMR-0907018]
- U.S. Department of Energy, Office of Basic Energy Science, Division of Materials Science [DEFG02-02ER46019]
Single-molecule fluorescence imaging of adsorption onto initially bare surfaces shows that polymer chains need not localize immediately after arrival. In a system optimized to present limited adsorption sites (quartz surface to which polyethylene glycol (PEG) chains adsorb from aqueous solution at pH 8.2), we find that some chains diffuse back into bulk solution and readsorb at some distance away, sometimes multiple times before they either localize at a stable position or diffuse away into bulk solution. This mechanism of surface diffusion is considerably more rapid than the classical model in which adsorbed polymers crawl on surfaces while the entire molecule remains adsorbed, suggesting the conceptual generality of a recent report (Phys. Rev. Lett. 2013, 110, 256101) but in a new experimental system and with comparison of different chain lengths. We find the trajectories with jumps to follow a truncated Levy distribution of step size with limiting slope -2.5, consistent with a well-defined, rapid surface diffusion coefficient over the times we observe. The broad waiting time distribution appears to reflect that polymer chains possess a broad distribution of bound fraction: the smaller the bound fraction of a given chain, the shorter the surface residence time before executing the next surface jump.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据