Suspension prepregging of high performance thermoplastic polymer-carbon fiber composites has great potential if the process can be performed with aqueous based suspensions and high thermal stability materials. In this study, submicrometer size particles were prepared by a nucleation and growth process, and a homogenization-solvent evaporation approach. Two thermally stable suspending agents were synthesized and utilized for particle fabrication. Polyacrylonitrile and pitch based carbon fibers were treated with heated ozone to form hydroxyl, carbonyl, and carboxylic acid groups on their surfaces, then reacted with a cyclic azasilane to produce surface-tethered amino groups. PEI particles coated with ionic, high performance, suspending agents were attracted electrostatically to the silanized carbon fibers. Scanning electron microscopy showed the functionalized carbon fibers were substantially covered with the particles. Thermally stable, coated, PEI particles can be fabricated and dispersed in an aqueous media, and particles can be incorporated in carbon fiber reinforced polymer composites.