Research Of Porous Hydrogen Bonding Network Structures At The Liquid-solid Interface

The assembled structures of triangular symmetrically shape molecules withthree functional groups, trimesic acid (TMA) and melamine, have been investigatedby scanning tunneling microscopy (STM) on highly oriented pyrolytic graphite(HOPG) in ambient. Hexagonal porous structures are formed by these molecules,and the cavity within the assembled structure formed by TMA is big enough to hostguest molecule.The self-assembled structures of these two kinds of molecules do not changewith the ambient temperature. When higher concentration soluiton is used to fabriatethe assembled molecular layer, the solvent molecules (pelargonic acid) in the cavitiesof the assembled structure formed by TMA molecules are replaced by the solutemolecule (TMA).The self-assembly behavior of melamine and TMA molecule have been alsostudied at the liquid/graphene interface by STM. Although the self-assembledstructure of melamine molecules on graphene is still the hexamer structure, the spacebetween the hexamers becomes wider. However, the assembled structure of TMA ongraphene is completely different from the hexagonal porous structure and molecularchains structure found on HOPG and is described as honeycomb structure. Thedifferences on the assembled structures of melamine and TMA on HOPG andgraphene suggests that the assembled structures of these moleucles are truly affectedby the interactions between the molecules and the substrates.