We here demonstrate the utilization of reactive layer-by-layer (rLBL) assembly to form a nanogel coating made of branched polyethylenimine (BPEI) and alkyne containing polyester (PE) on a gold surface. The rLBL is generated by the rapid aza-Michael addition reaction of the alkyne group of PE and the −NH₂ groups of BPEI by yielding a homogeneous gel coating on the gold substrate. The thickness profile of the nanogel revealed that a 400 nm thick coating is formed by six multilayers of rLBL, and it exhibits 50 nm roughness over 8 μm distance. The LBL characteristics were determined via depth profiling analysis by X-ray photoelectron spectroscopy, and it has been shown that a 70–100 nm periodic increase in gel thickness is a consequence of consecutive cycles of rLBL. A detailed XPS analysis was performed to determine the yield of the rLBL reaction: the average yield was deduced as 86.4% by the ratio of the binding energies at 286.26 eV, (C═CN–C bond) and 283.33 eV, (C≡C triple bond). The electrochemical characterization of the nanogels ascertains that up to the six-multilayered rLBL of BPEI-PE is electroactive, and the nanogel permeability had led to drive mass and charge transfer effectively. These results promise that nanogel formation by rLBL films may be a straightforward modification of electrodes approach, and it exhibits potential for the application of soft biointerfaces.

中文翻译：

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聚酯和支化聚乙烯亚胺通过 Aza-Michael 加成反应逐层组装形成电活性纳米凝胶

我们在这里展示了利用反应性逐层 (rLBL) 组装在金表面上形成由支化聚乙烯亚胺 (BPEI) 和含炔聚酯 (PE) 制成的纳米凝胶涂层。rLBL 由 PE 的炔基与 -NH ₂的快速氮杂-迈克尔加成反应生成通过在金基材上产生均匀的凝胶涂层来制备 BPEI 基团。纳米凝胶的厚度分布表明，400 nm 厚的涂层由六层 rLBL 形成，并且在 8 μm 距离上表现出 50 nm 的粗糙度。LBL 特性是通过 X 射线光电子能谱的深度剖面分析确定的，并且已经表明凝胶厚度的 70-100 nm 周期性增加是 rLBL 连续循环的结果。进行详细的 XPS 分析以确定 rLBL 反应的产率：通过 286.26 eV（C=CN-C 键）和 283.33 eV（C≡C三键）。纳米凝胶的电化学表征确定 BPEI-PE 的六层 rLBL 具有电活性，并且纳米凝胶的渗透性导致有效地驱动质量和电荷转移。这些结果表明，通过 rLBL 薄膜形成纳米凝胶可能是电极方法的直接修改，并且它显示出软生物界面应用的潜力。