Switching Two-Dimensional Sliding Ferroelectrics by Mechanical Bending.

Two-dimensional van der Waals materials, possessing a unique stacking degree of freedom, offer an alternative strategy for modulating their properties through interlayer sliding. Controlling the stacking order is crucial for tuning material properties and developing slidetronics-based devices. Here, using machine-learning potentials, we propose a mechanical bending approach to manipulate stacking orders and related properties in sliding ferroelectric h-BN, 3R-MoS_{2}, and nonferroelectric bilayer graphene.

Detection of alkanolamines in liquid cement grinding aids by HPLC coupled with evaporative light scattering detector.

Triethanolamine (TEA), triisopropanolamine (TIPA), diethanol isopropanolamine (DEIPA) are necessary cement additives, and knowing their contents is needed for quality control and also to understand final properties of the cement. Whether it is the production of grinding aids, technical research and development or application research all involve the detection of grinding aids. This work developed a simple analytical technique for the simultaneous analysis of these alkanolamines in liquid cement grinding aids using high-performance liquid chromatography (HPLC) combined with evaporative light scattering detection (ELSD).

Copper-mediated domino process for the synthesis of tetraiodinated di(perylene bisimide).

Tetraiodinated di(perylene bisimide) has been prepared from tetrabrominated perylene bisimide by the combination of Ullmann-type coupling, C-H transformation, and halogen-exchange. The crystal structure analysis confirmed that the aromatic core is quite distorted because of the electrostatic repulsion and steric encumbrance of iodine substituents in the bay regions.

Air-stable n-type semiconductor: core-perfluoroalkylated perylene bisimides.

A series of core-perfluoroalkylated perylene bisimides (PBIs) have been efficiently synthesized by copper-mediated perfluoroalkylation of dibrominated PBIs. Their aromatic cores are highly twisted due to the steric encumbrance in the bay regions as revealed by single-crystal X-ray analysis. The organic field-effect transistors (OFETs) incorporating these new n-type semiconductors show remarkable air-stability and good field effect mobility.