Thrust 3 - Templating of Ordered Nanostructures
Magnetic nanoparticles dispersed in a polymer matrix. Magnetic nanoparticles dispersed in a polymer thin film form the active recording layer in magnetic tape. To enhance the density of data that can be stored magnetically in such a composite thin film, it is desirable to use small (nanoscale) particles, at high loadings (>50% by weight), and to disperse these nanoparticles evenly within the polymer matrix. In addition, the nanoparticles must be ferromagnetic with large magnetic dipoles at room temperature to be useful for storing data. Dispersing such ferromagnetic nanoparticles evenly within the polymer matrix is problematic due to the strong interparticle magnetic forces, which tend to induce aggregation and agglomeration.
Figure 2. Dispersion of carboxylate-coated silica particles. Molecular recognition between the magnetic nanoparticles and a high-performance polymer matrix may be a viable option for creating a solution-deposited medium that controls the dispersion of the particles.
In a multidisciplinary collaboration, Milliron, Nelson, Pratt, Wade, and Hedrick developed thermally robust polymers that employ molecular recognition for dispersing FePt nanoparticles. Complementary hydrogen bonding components, such as urea-carboxylate or urea-naphthyridine functionalities (Figure 1), were incorporated into the polymer backbone and nanoparticle surface. Our preliminary investigations have revealed that poly(arylether)ketones possessing urea functionalities are effective for creating dispersions of carboxylate-bearing silica particles (Figure 2).