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首页> 外文期刊>Macromolecules >Using miscible polymer blends to control depletion-attraction forces between Au nanorods in nanocomposite films
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Using miscible polymer blends to control depletion-attraction forces between Au nanorods in nanocomposite films

机译：使用可混溶的聚合物共混物来控制纳米复合薄膜中金纳米棒之间的耗尽力

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摘要

To fully utilize their optical absorption and polarizing abilities, the dispersion of Au nanorods (NRs) in a matrix, such as a polymer film, must be controlled. By functionalizing NRs with a polymer brush chemically similar to the matrix, NR dispersion and aggregation can be controlled by varying the ratio of brush (N) to matrix (P) chain length. For P/N > 2, aggregates containing mainly side-by-side arrangements of NRs are observed. Here, polystyrene (PS) functionalized Au NRs are incorporated into miscible thin film blends of PS and poly(2,6-dimethyl-p-phenylene oxide) (PPO) (P/N ≈ 30) and characterized using a combination of transmission electron microscopy (TEM) and UV-visible spectroscopy (UV-vis). As the volume fraction of PPO (φ _(PPO)) increases from 0.00 to 0.50, the NRs remain mainly aggregated; however, at φ _(PPO) = 0.75 they begin to disperse and finally completely disperse in a pure PPO matrix. Correspondingly, the longitudinal surface plasmon resonance peak undergoes a red shift, consistent with improved dispersion (i.e., individual NRs). A novel outcome of this work is to utilize UV-vis to detect nanometer-scale changes in Au nanorod dispersion. To understand the role of the PPO matrix chains, which favorably interact with the PS brush, self-consistent field theory (SCFT) calculations were performed to determine the brush and matrix density profiles. The brush profile is initially parabolic for φ _(PPO) < 0.25 and has a thickness that is nearly the radius of gyration of the brush. However, for φ _(PPO) = 0.50, the brush begins to stretch because of PPO matrix chain penetration. Finally, for φ _(PPO) = 0.75 and 1.00, the brush thickness increases by about 50%. These SCFT results help interpret the dispersion of nanorods determined from TEM and UV-vis.
机译：为了充分利用它们的光吸收和偏振能力，必须控制Au纳米棒（NRs）在基质（例如聚合物膜）中的分散。通过使用化学性质类似于基体的聚合物刷功能化NR，可以通过改变刷（N）与基体（P）链长的比率来控制NR的分散和聚集。对于P / N> 2，观察到主要包含NR并排排列的聚集体。在此，将聚苯乙烯（PS）功能化的金NR掺入PS和聚（2,6-二甲基-对苯撑氧）（PPO）（P / N≈30）的可混溶的薄膜共混物中，并使用透射电子的组合进行表征显微镜（TEM）和紫外可见光谱（UV-vis）。随着PPO（φ_（PPO））的体积分数从0.00增加到0.50，NR仍主要聚集;但是，在φ_（PPO）= 0.75时，它们开始分散，最终完全分散在纯PPO基质中。相应地，纵向表面等离子体激元共振峰经历红移，这与色散的改善（即，各个NR）一致。这项工作的新颖成果是利用紫外线可见光检测金纳米棒分散液中的纳米级变化。为了了解可以与PS笔刷良好交互的PPO矩阵链的作用，进行了自洽场论（SCFT）计算以确定笔刷和矩阵的密度分布。刷子轮廓最初是φ_（PPO）<0.25的抛物线形，并且其厚度接近刷子的回转半径。但是，对于φ_（PPO）= 0.50，由于PPO基质链渗透，刷子开始伸展。最后，对于φ_（PPO）= 0.75和1.00，笔刷厚度增加约50％。这些SCFT结果有助于解释由TEM和UV-vis确定的纳米棒的分散性。

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