Self-assembly of hydrophobic polybetaine based on (tridecyl)aminocrotonate and methacrylic acid

Novel polymeric betaine based on tridecylaminocrotonate and methacrylic acid was synthesized by Michael addition reaction. The obtained products were abbreviated as CROtriDA-MAA and with respect to its potassium salt as CROtriDA-MAA-K. The structure of CROtriDA-MAA was established by 1H NMR and FTIR spectroscopy. The hydrodynamic, molecular and conformational properties of CROtriDA-MAA-K in solutions and morphology in solid state were evaluated by methods of GPC, DLS, zeta-potential, surface enhanced ellipsoidal microscopy (SEEC), optical microscopy. Meanwhile, the long alkyl “tails” (tridecyl) located in side polymeric chains are responsible for self-assembling behavior. Several types of self-assembled structures in water at different pH and in water–DMSO mixture were observed. The dendritic structure with wide trunks and few side branches is formed at pH 3. The “Maltese cross-like” aggregates were found at pH 6.5. The tree-like fractal patterns are formed at pH 12. The self-assembled coiled-ribbon-like and tubular-like aggregates were observed in water–DMSO mixtures.