Anion-dipole interactions regulating the self-assembled nanostructures of polymers

The morphology controls of formed polymer nanomaterials are very important for developing suitable nanomaterials. Generally, to regulate the assembled morphology of polymers, we should alter the lengths of the block segments, the chemical structures or the selectivity of the solvent. Here, when we added NaSCN into poly(2-(2-(2-methoxyethoxy)ethoxy)ethyl methacrylate) (PMEO(3)MA) aqueous solution, dipole-anion interactions occurred between the weakly hydrated SCN-anions and the slightly positively charged CHn groups next to the O atoms in the PMEO(3)MA chain. We used H-1 NMR and isothermal titration microcalorimetry (ITC) to confirm the formation of the dipole-anion interactions. Furthermore, TEM and SEM results show that the anion-dipole interactions can regulate the self-assembly of PMEO(3)MA into nanostructures with different morphologies. A corresponding mechanism is proposed to explain the regulation of the morphology.