Cholesterol mesogen containing water-soluble copolymers: design and organization behavior at different interfaces.

Cholesterol mesogen containing monomer, cholesteryl acrylamido butyrate (CAB) with the novel spacer group drawn from 4-amino butyric acid has been demonstrated to exhibit good reactivity with 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) to yield copolymers with CAB content as high as 15 mol % hitherto not achieved. The spacer group is shown to provide the twin benefits of enhanced reactivity and solubility in water. The high pK(a) at > or =9.90 of these copolymers estimated from potentiometric studies demonstrates packing of AMPS segments as ionic clusters. The higher CAB in copolymer C provides the most densely packed nonpolar microdomains. From fluorescence quenching studies, the cross-linking provided by the cholesterol chains favoring intra- or intermolecular aggregated structures has been established. At the air/solution interface, copolymer C exhibits the most close-packed structures exhibiting "a" of 41.2 A(2)/molecule. The effect of neutralization on the adsorption characteristics is investigated.