The crystal packing, morphology and hydrophobicity of polyoxometalate-based amphiphilic materials

Four amphiphilic hybrids based on polyoxovanadate with hydrophobic tails of different quantities and lengths were successfully synthesized. In particular, three crystal structures of the amphiphilic hybrids have been confirmed by single crystal XRD and their manner of packing has been investigated to reveal the driving force of the crystal stacking. Furthermore, the morphologies and microstructures of the products were studied using SEM and TEM. Their wettabilities were also measured by the contact angle method. The results indicated that the increase of the single alkyl chain length could be beneficial to the crystal packing. Increasing the quantity of the alkyl chains was detrimental to crystal growth but could lead to smoother and hydrophobic material surfaces. Crystal structures of polyoxometalate-based amphiphiles with multiple alkyl tails were characterized by single crystal X-ray diffraction to reveal the relationship between morphologies and manner of packing.