Alignment of carbon nanotubes comprising magnetically sensitive metal oxides in nanofluids

A nanofluid comprising:

• one or more nonmagnetically sensitive nanoparticles comprising carbon nanoparticles, one or more magnetically sensitive nanoparticles, and one or more surfactants;
• wherein the nonmagnetically sensitive nanoparticles, magnetically sensitive nanoparticles, and one or more surfactants are dispersed in a fluid;
• wherein the fluid has a pH greater than about 5 and the surfactants have a net negative charge, or the fluid has a pH less than about 9 and the surfactants have a net positive charge;
• wherein at least a portion of the nonmagnetically sensitive nanoparticles are aligned;
• and
• wherein the nanofluid exhibits an increase of thermal conductivity of at least about 10%.

A nanoparticle composition prepared by the process comprising:

• combining one or more nonmagnetically sensitive nanoparticles, one or more magnetically sensitive nanoparticles, and one or more surfactants;
• dispersing one or more nonmagnetically sensitive nanoparticles, one or more magnetically sensitive nanoparticles, and one or more surfactants in a dispersion;
• and
• exposing the dispersion and its contents to a magnetic field, wherein the nanoparticle composition exhibits an increase of thermal conductivity of at least about 10%.