Three types of fullerene (C-60)-end-capped poly(4-diphenylaminostyrene) (C-60-PDAS) and poly(4-diphenylaminostyrene) (PDAS) blends were prepared to investigate their potential as bipolar polymer semiconductors. The concentration of C-60 in the C-60-PDAS/PDAS blends strongly affected the hole and electron drift mobility values; the hole drift mobility decreased with an increase in the C-60 concentration. However, the electron drift mobility increased with an increase in the C-60 concentration. The hole and electron drift mobility values were almost the same for the 1/2 C-60-PDAS/PDAS blend; therefore, this polymer blend was thought to be a bipolar polymer semiconductor. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 3433-3438, 2011