A novel, positively charged membrane was prepared through a blending, crosslinking, and coagulation procedure in which poly(N,N-dimethylaminoethyl methacrylate) (PDM) and polyacrylonitrile (PAN) were used as the functional and substrate component, respectively. Because 1,4-dibromobutane (DBT) was used as the crosslinker and quaternizing agent, PDM was crosslinked and quaternized simultaneously. The effects of PDM content, polymer concentration, and additive dosage of the casting solution on the membrane performances are discussed in detail, and differences between the PAN membrane, PDM/PAN blend membrane, and crosslinked PDM/PAN blend membrane are also discussed. We also studied the adsorption behaviors of the membranes to a positively charged dye and a negatively charged dye. Environmental scanning electron microscopy observation showed that the resulting positively charged membrane from such a blending, crosslinking, and coagulation procedure possessed a unique and uniform structure. (c) 2005 Wiley Periodicals, Inc.