| STUDY |
ANOTHER TYPE of diblock copolymer that is being studied is one in which both blocks are hydrophilic but one is charged and the other is neutral. An example is poly(sodium acrylate)-poly(acrylamide) (PANa-PAM); here the first block is anionic. On their own in water, these polymers simply dissolve. In the presence of cationic surfactants, they form complexes with surfactant micelles in the core. And in the presence of multivalent cations, they form complexes with ions in the core. Author says these results present a way to introduce cationic surfactants in formulations and to access stable nanoparticles. "We expect a lot of applications from this work," he adds. Studies by authors indicate that the aggregates formed by PANa-PAM with surfactants are colloids with radii of about 400 Å--much bigger than what might be expected on the basis of the sizes of the surfactant and polymer molecules. Neutron- and light-scattering experiments suggest a core-shell microstructure. Surfactant micelles held together by the polyelectrolyte blocks make up the core, which is surrounded by a corona of neutral chains. Author says the complexation can be controlled so that the core is not always spherical but could be cylindrical. The aggregate also can be destabilized by the addition of salt or acid. A tantalizing possibility is for reactions to take place in the core, but so far no applications in that direction are being explored |
| UPDATE | 08.03 |
| AUTHOR | This data is not available for free |
| LITERATURE REF. | This data is not available for free |
|
Want more information ? Interested in the hidden information ? Click here and do your request. |