In-plane Van der Waals interactions of molecular self-assembly monolayer

We demonstrate that the Van der Waals interactions in plane are important to control molecular self-assembly structure as well their phase transition. Using precise chemical modification to mediate such in-plane cohesive interactions, we observed the spontaneous formations of 2D order or disorder molecular self-assembly structures, as well their order-disorder phase transitions by annealing. Interestingly, we identified that the side alkyl chains stand up at surfaces and form the 'locked' pairs/windmill structures. Moreover, we realized the covalent coupling based on ethynyl functionality before molecular desorption from metal surfaces, by enhancing the in-plane interactions. (C) 2015 AIP Publishing LLC.