Synthesis, structure and morphology of organic layered double hydroxide (LDH) hybrids: Comparison between aliphatic anions and their oxygenated analogs

摘要

Intercalation of organic anions is an important aspect of layered double hydroxide (LDH) chemistry in the development of polymer-LDH composites. In the research, we intercalated short and lengthy straight-chain organic anions with the carbon number up to 50 into the interlayer of MgAl and ZnAl-LDHs. We also noted that the packing mode of the straight-chain organic species and the basal spacing are somewhat predictable. In most cases, the hydrocarbon chain (or oxygenated) is packed in an anti-parallel inter-penetrating style at an angle of around 55°. Only when the hydrocarbon chain contains 14-18 carbons and the supplied amount of the organic anion is more than the anion exchange capacity, a so-called bi-layer packing mode is also observed. Due to the variety in the structure and property of organic hydrocarbon chains, the organo-LDH crystallites show various morphologies, where the hydrophobic forces are expected to play an important role in determining the crystallite shape.