Adamo Fabrizio Corrado, Ciuchi Federica, De Santo Maria Penelope, Astolfi Paola, Warner Isabelle, Scharrer Eric, Pisani Michela, Vita Francesco, Francescangeli Oriano
SIMAU Department, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona, Italy.
CNR-Nanotec c/o Physics Department, University of Calabria, Ponte Bucci, Cubo 31C, 87036 Arcavacata di Rende, Italy.
Nanomaterials (Basel). 2022 Jul 2;12(13):2285. doi: 10.3390/nano12132285.
Bent-core mesogens (BCMs) are a class of thermotropic liquid crystals featuring several unconventional properties. However, the interpretation and technological exploitation of their unique behavior have been hampered by the difficulty of controlling their anchoring at surfaces. To tackle this issue, we report the nanoscale structural characterization of BCM films prepared using the Langmuir-Blodgett technique. Even though BCMs are quite different from typical amphiphilic molecules, we demonstrate that stable molecular films form over water, which can then be transferred onto silicon substrates. The combination of Brewster angle microscopy, atomic force microscopy, and X-ray reflectivity measurements shows that the molecules, once transferred onto a solid substrate, form a bilayer structure with a bottom layer of flat molecules and an upper layer of upright molecules. These results suggest that Langmuir-Blodgett films of BCMs can provide a useful means to control the alignment of this class of liquid crystals.
弯曲核液晶（BCMs）是一类具有多种非常规特性的热致液晶。然而，由于难以控制它们在表面的锚定，其独特行为的解释和技术开发受到了阻碍。为了解决这个问题，我们报告了使用朗缪尔-布洛杰特技术制备的BCM薄膜的纳米级结构表征。尽管BCMs与典型的两亲分子有很大不同，但我们证明在水面上会形成稳定的分子薄膜，然后可以将其转移到硅基板上。布鲁斯特角显微镜、原子力显微镜和X射线反射率测量结果表明，这些分子一旦转移到固体基板上，就会形成双层结构，底层是平躺的分子，上层是直立的分子。这些结果表明，BCMs的朗缪尔-布洛杰特薄膜可以提供一种有用的方法来控制这类液晶的排列。
