Langmuir. 2018 May 15;34(19):5454-5463. doi: 10.1021/acs.langmuir.8b00553. Epub 2018 Apr 30.
Polymerizable amphiphiles can be assembled into lying-down phases on 2D materials such as graphite and graphene to create chemically orthogonal surface patterns at 5-10 nm scales, locally modulating functionality of the 2D basal plane. Functionalization can be carried out through Langmuir-Schaefer conversion, in which a subset of molecules is transferred out of a standing phase film on water onto the 2D substrate. Here, we leverage differences in molecular structure to spatially control transfer at both nanoscopic and microscopic scales. We compare transfer properties of five different single- and dual-chain amphiphiles, demonstrating that those with strong lateral interactions (e.g., hydrogen-bonding networks) exhibit the lowest transfer efficiencies. Since molecular structures also influence microscopic domain morphologies in Langmuir films, we show that it is possible to transfer such microscale patterns, taking advantage of variations in the local transfer rates based on the structural heterogeneity in Langmuir films. Nanoscale domain morphologies also vary in ways that are consistent with predicted relative transfer and diffusion rates. These results suggest strategies to tailor noncovalent functionalization of 2D substrates through controlled LS transfer.
可聚合两亲分子可以在二维材料（如石墨和石墨烯）上组装成躺下相，从而在 5-10nm 尺度上创建化学正交的表面图案，局部调节二维基底平面的功能。功能化可以通过 Langmuir-Schaefer 转换来进行，其中一部分分子从水面上的站立相膜转移到二维基底上。在这里，我们利用分子结构的差异在纳米和微观尺度上空间控制转移。我们比较了五种不同的单链和双链两亲分子的转移性质，表明具有强横向相互作用（例如氢键网络）的那些分子具有最低的转移效率。由于分子结构也会影响 Langmuir 膜中的微观畴形态，因此我们表明可以利用 Langmuir 膜中局部转移率的变化来转移这种微尺度图案，从而利用结构异质性。纳米尺度的畴形态也以与预测的相对转移和扩散速率一致的方式发生变化。这些结果表明，通过控制 LS 转移来定制二维基底的非共价功能化的策略。
