Synthesis of graft polyacrylamide with responsive self-assembling properties in aqueous media

Graft copolymers with water-soluble backbones were prepared using two different routes: grafting onto and grafting through techniques. The corresponding syntheses, leading to ionic or non-ionic copolymers, are described here in detail and exemplified with various primary structures obtained by changing the chemical nature of the side chains or the grafting ratio. Depending on the polyelectrolyte or neutral character of water-soluble backbones, viscosity-concentration dependences were determined at room temperature in dilute and semi-dilute regimes. Upon heating, PNIPA grafts dehydrate and self-aggregate into hydrophobic microdomains which promote the formation of a physical network above 36 °C. The main features of the thermoassociating properties of the copolymers in aqueous solutions are described using different experimental approaches: rheology, calorimetry, NMR spectroscopy and neutron scattering.