Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.
Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, United States.
ACS Nano. 2021 Jun 22;15(6):10275-10285. doi: 10.1021/acsnano.1c02414. Epub 2021 May 17.
Nanocrystals are often synthesized using technical grade reagents such as oleylamine (OLAm), which contains a blend of octadeceneamine with -unsaturated and saturated amines. Here, we show that gold nanowires (AuNWs) synthesized with OLAm ligands undergo thermal transitions in interfacial assembly (ribbon . nematic); transition temperatures vary widely with the batch of OLAm used for synthesis. Mass spectra reveal that higher-temperature AuNW assembly transitions are correlated with an increased abundance of and saturated chains in certain blends. DSC thermograms show that both pure (synthesized) and technical-grade OLAm have primary melting transitions near -5 °C (20-30 °C lower than the literature melting temperature range of OLAm). A second, broader melting transition (in the previous reported melting range) appears in technical grade blends; its temperature varies with the abundance of and saturated chains. Our findings illustrate that, similar to biological membranes, blends of alkyl chains can be used to generate mesoscopic hierarchical nanocrystal assembly, particularly at interfaces that further modulate transition temperatures.
纳米晶体通常使用技术级试剂（如油胺（OLAm））合成，其中包含十八烯胺与 -不饱和和饱和胺的混合物。在这里，我们表明，用 OLAm 配体合成的金纳米线（AuNWs）在界面组装（带状. 向列）中经历热转变; 转变温度随用于合成的 OLAm 批次而广泛变化。质谱表明，更高温度的 AuNW 组装转变与某些混合物中 和饱和链的丰度增加有关。差示扫描量热法（DSC）图谱表明，纯（合成）和技术级 OLAm 在接近 -5°C 的温度下都有主要的熔融转变（比文献中 OLAm 的熔融温度范围低 20-30°C）。在技术级混合物中出现第二个更宽的熔融转变（在前述报道的熔融范围内）; 其温度随 和饱和链的丰度而变化。我们的发现表明，与生物膜类似，烷基链的混合物可用于生成介观分级纳米晶体组装，特别是在进一步调节转变温度的界面处。
