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首页> 外文期刊>ACS Macro Letters >Interfacial Irreversibly and Loosely Adsorbed Layers Abide by Different Evolution Dynamics
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Interfacial Irreversibly and Loosely Adsorbed Layers Abide by Different Evolution Dynamics

机译：界面不可逆转地和松散的吸附层遵守不同的演化动力学

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摘要

Within the interfacial region of the substrate, polymer chains can form the inner irreversibly adsorbed and outer loosely adsorbed layers upon annealing. Owing to their different constrained environments, the evolution dynamics of the two layers are supposedly different. To trace such evolution dynamics, we thus resorted to sum frequency generation (SFG) vibrational spectroscopy, using polystyrene (PS) with a series of molar masses on sapphire substrates. By plotting the integrated SFG intensity as a function of the annealing time, we found that the inner irreversibly adsorbed layer had two segmental evolution processes (replacement and local structural relaxation), and the outer loosely adsorbed layer had the monotonical evolution dynamics (structural relaxation), with both evolving toward the dissipation of the interfacial molecular order of the backbones. A critical evolution time was defined for the inner irreversibly adsorbed layer, and a characteristic relaxation time was defined for the outer loosely adsorbed layer. With respect to the molar mass, phenomenologically, both the critical evolution time and the characteristic relaxation time show an asymptotic increase. In summary, this SFG investigation provides the first-hand experimental data on understanding the structural evolution dynamics of the interfacial adsorbed polymer chains, which would gradually split up into the irreversibly adsorbed layer and loosely adsorbed layer upon annealing.
机译：在基材的界面区域内，在退火时，聚合物链可以在内部不可逆地吸附和外部松散吸附的层。由于其不同的受限环境，两层的演化动态据说是不同的。为了追踪这种进化动力学，我们采取了使用聚苯乙烯（PS）的频率产生（SFG）振动光谱，其在蓝宝石基材上具有一系列摩尔质量。通过根据退火时间的函数绘制集成的SFG强度，我们发现内部不可逆的吸附层具有两个节段性演化过程（更换和局部结构松弛），外部松散吸附层具有单调的演化动力学（结构松弛） ，两者都朝向骨干的界面分子阶的耗散。为内部不可逆吸附层定义临界演化时间，并且为外部松散吸附层定义特征弛豫时间。关于摩尔物质，临界演化时间和特征松弛时间都显示出渐近增加。总之，该SFG调查提供了关于了解界面吸附聚合物链的结构演化动态的第一手实验数据，这将逐渐在退火时逐渐分成不可逆吸附的层并松散地吸附层。

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  • 来源
    《ACS Macro Letters》 |2019年第11期|共6页
  • 作者

    Li Xu; Lu Xiaolin;

  • 作者单位

    Southeast Univ Sch Biol Sci &

    Med Engn State Key Lab Bioelect Nanjing 210096 Jiangsu Peoples R China;

    Southeast Univ Sch Biol Sci &

    Med Engn State Key Lab Bioelect Nanjing 210096 Jiangsu Peoples R China;

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  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 有机化学;
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