Self-Assembly of Substituted Polyglutamates on Solid Substrates: The Side-Chain Effect

The effect of the length of the side chain in substituted polyglutamates on the self-assembly of these polymers on hydrophilic and hydrophobic substrates was studied, using atomic force microscopy. While the primary layer on hydrophilic surfaces featured a fiber-like morphology regardless of the length of the side group, the layers assembled atop the first layer showed a strong dependence on the pendant side substituent. Polyglutamates with short side chains formed a well-developed fiber-like structure, while the assembly of molecules with long substituents produced a peculiar flower-like morphology. The difference in the morphologies of polyglutamate multilayers was ascribed to the different driving forces of the molecular association.