Surfactant Induced Mesomorphic Behaviour of Flexible Polymers

Conditions for micro phase separated structures based on flexible polymers associated with surfactants have been investigated. Reasonably strong attractive interactions are required to oppose macro phase separation between polymer and surfactant. In order to obtain micro phase separation, additionally a sufficiently strong polar-nonpolar repulsion has to be present. Poly(4-vinyl pyridine), poly(2-vinyl pyridine) and polyamide 6 have been used as model polymers in this work. Associations based on protonation, metal coordination and hydrogen bonding are presented and shown to yield micro phase separation under suitable conditions. In the charged systems, the polar-nonpolar repulsion easily becomes large enough to render micro phase separated structures. In hydrogen bonded (i.e. noncharged) systems a more delicate balance can be achieved in which case an order-disorder transition takes place from a homogeneous state, exhibiting nonetheless a distinct SAXS peak due to characteristic block copolymer-like fluctuations, to a micro phase separated ordered state.